:root {
            --transport-frame-pad-y: 10px;
            --transport-frame-pad-x: 12px;
            --transport-frame-border: 1px;
            --transport-frame-inner-h: 24px;
            --transport-frame-outer-h: calc(
                2 * var(--transport-frame-pad-y) + var(--transport-frame-inner-h) + 2 * var(--transport-frame-border)
            );
            --accent: #ff9933;
            --accent-mid: #e57a1c;
            --accent-deep: #8a3d00;
            --accent-ink: #e07018;
            --accent-soft: #e09040;
            --accent-glow: rgba(255, 153, 51, 0.5);
            --accent-glow-weak: rgba(255, 153, 51, 0.14);
            --accent-border: rgba(255, 180, 120, 0.45);
            --accent-track-1: #1c0f07;
            --accent-track-2: #301806;
            --accent-track-3: #4a280c;
            --transport-opt-font-size: 0.76rem;
            /* オプション枠内のコントロール高（select と揃え、3 枠の高さを一致させる） */
            --transport-opt-control-h: 30px;
            --transport-opt-box-min-h: calc(
                2 * var(--transport-frame-pad-y) + var(--transport-opt-control-h) + 2 * var(--transport-frame-border)
            );
            /** シーク行: 現在 / 総尺の枠と再生ボタンの外寸を揃える（button の UA 余白込みで少し高め） */
            --transport-seek-align-h: 36px;
            /*
             * 文字色の役割（sample.html と同じ分担。サンプルのシアン #7dd8ff は --app-accent に相当）
             *   --app-doc-text … 折りたたみ本文・マニュアル本文・箇条書き（sample: .app-doc-fold__body #d4dbe6）
             *   --app-accent … マニュアル h3/h4、本文内リンク、フッター内リンク、トランスポートの時刻・数値強調など
             *                   （sample では見出し・リンク・#playStopBtn 付近の値表示などに同一トーン #7dd8ff）
             *   インライン code … 本文と同色（inherit。sample に code 専用色はなし）
             *   ショートカット表 … ベース #b4bcc8 / 表見出し #c8d0dc / 先頭列 #d0d8e4（sample と同じ固定色）
             *   フッター … 外周 #8a92a4 / コピーライト #9aa4b8 / リンクは --app-accent（sample は #7dd8ff）
             */
            --app-doc-text: #d4dbe6;
            --app-accent: var(--accent-ink);
            --app-shortcut-text: #b4bcc8;
            --app-shortcut-heading: #c8d0dc;
            --app-shortcut-col1: #d0d8e4;
        }
        body {
            font-family: system-ui, -apple-system, 'Segoe UI', sans-serif;
            background: #141418;
            color: #f0f0f5;
            padding: 8px 20px 20px;
            margin: 0;
            max-width: none;
            width: 100%;
            box-sizing: border-box;
        }

        .layout-narrow {
            max-width: 1300px;
            margin-left: auto;
            margin-right: auto;
            width: 100%;
            box-sizing: border-box;
        }

        .app-header {
            margin: 0 0 18px;
            padding: 18px 0 16px;
            display: flex;
            justify-content: center;
            align-items: center;
            text-align: center;
        }
        .app-header-inner {
            display: inline-flex;
            flex-wrap: nowrap;
            align-items: flex-end;
            justify-content: center;
            gap: 12px;
            max-width: 100%;
            transform: translateX(calc((3.35rem + 12px) / 2));
        }
        h2.app-title {
            margin: 0;
            font-size: 1.55rem;
            font-weight: 700;
            letter-spacing: -0.03em;
            color: #eef2f8;
            text-align: center;
            line-height: 1;
            text-decoration: none;
            box-sizing: border-box;
            align-self: flex-end;
        }
        .version-badge {
            font-size: 11px;
            background: linear-gradient(180deg, var(--accent) 0%, var(--accent-mid) 48%, var(--accent-deep) 100%);
            color: #1a0f08;
            padding: 3px 10px;
            border-radius: 999px;
            vertical-align: middle;
            margin-left: 10px;
            font-weight: 800;
            border: 1px solid var(--accent-border);
            box-shadow: 0 2px 10px var(--accent-glow-weak);
        }
        .app-header .version-badge {
            margin-left: 0;
            flex-shrink: 0;
            line-height: 1.1;
            box-sizing: border-box;
            align-self: flex-end;
            vertical-align: unset;
            display: inline-flex;
            align-items: center;
            justify-content: center;
        }

        #main-drop-zone {
            background: linear-gradient(165deg, #2a2a32 0%, #1a1a20 100%);
            padding: 24px 22px 22px;
            min-height: 5.5em;
            border-radius: 14px;
            border: 3px dashed rgba(255, 255, 255, 0.22);
            text-align: center;
            margin-bottom: 18px;
            cursor: pointer;
            transition: border-color 0.25s, box-shadow 0.25s, background 0.25s;
            box-shadow: 0 8px 28px rgba(0, 0, 0, 0.35), inset 0 1px 0 rgba(255, 255, 255, 0.04);
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            gap: 8px;
            box-sizing: border-box;
        }
        #main-drop-zone:hover {
            background: linear-gradient(165deg, #34343e 0%, #222228 100%);
            border-color: rgba(255, 153, 51, 0.72);
            box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4), 0 0 24px var(--accent-glow-weak);
        }
        #main-drop-zone.dragover {
            border: 3px dashed var(--accent);
            background: linear-gradient(165deg, #352a22 0%, #221a16 100%);
        }
        #main-drop-zone .drop-zone-title {
            color: #c8d0e0;
            font-size: 0.95em;
            letter-spacing: 0.03em;
            margin: 0;
            line-height: 1.4;
        }
        #main-drop-zone .drop-zone-note {
            margin: 0;
            font-size: 0.76em;
            font-weight: 500;
            color: #8e96a8;
            line-height: 1.45;
            max-width: 42rem;
        }
        #main-drop-zone .drop-zone-note--privacy {
            color: #ff3333;
        }

        /** ブラウザ幅に追従（layout-narrow の外に配置） */
        .compare-stage {
            margin: 0 auto 18px;
            width: 100%;
            max-width: none;
            box-sizing: border-box;
        }
        /** 合成ビュー時は左右 2 パネルを完全に非表示（動画はスタック側へ移動済み） */
        .compare-stage--composite .compare-grid,
        .compare-grid[hidden] {
            display: none !important;
        }
        .compare-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 18px;
            margin: 0;
            width: 100%;
            max-width: none;
            box-sizing: border-box;
        }
        @media (max-width: 720px) {
            .compare-grid {
                grid-template-columns: 1fr;
            }
        }
        .video-panel {
            background: linear-gradient(165deg, #32323c 0%, #1f1f26 42%, #26262f 100%);
            padding: 16px 14px 18px;
            border-radius: 14px;
            border: 1px solid rgba(255, 255, 255, 0.06);
            box-shadow:
                0 14px 36px rgba(0, 0, 0, 0.42),
                inset 0 1px 0 rgba(255, 255, 255, 0.06);
            position: relative;
            overflow: hidden;
        }
        .video-panel::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            height: 3px;
            background: linear-gradient(90deg, #3a3a44, #555, #3a3a44);
            opacity: 0.85;
        }
        .video-panel.loaded::before {
            background: linear-gradient(90deg, var(--accent-deep), var(--accent), var(--accent-deep));
        }
        .video-panel-label {
            font-size: 0.72rem;
            font-weight: 700;
            letter-spacing: 0.12em;
            text-transform: uppercase;
            color: #8e96a8;
            margin: 0 0 8px;
            text-align: center;
        }
        .video-panel.loaded .video-panel-label {
            color: var(--app-accent);
        }
        .panel-info-line {
            margin: -4px 0 10px;
            font-size: 0.68rem;
            font-weight: 500;
            color: #7a8294;
            text-align: center;
            letter-spacing: 0.02em;
            line-height: 1.45;
            max-width: 100%;
            overflow-wrap: break-word;
            word-break: break-word;
        }
        .video-panel.loaded .panel-info-line {
            color: #b8c4d8;
        }
        .file-name {
            display: block;
            font-size: 0.78em;
            color: #5a5a68;
            font-weight: 500;
            text-align: center;
            overflow: hidden;
            text-overflow: ellipsis;
            white-space: nowrap;
            line-height: 1.3;
            letter-spacing: 0.02em;
            padding: 5px 10px;
            margin: 0 0 10px;
            border-radius: 8px;
            background: rgba(0, 0, 0, 0.12);
            border: 1px solid rgba(255, 255, 255, 0.028);
        }
        .video-panel.loaded .file-name {
            color: #e4e8f0;
            font-weight: 600;
            border-color: rgba(255, 153, 51, 0.22);
            background: rgba(50, 28, 0, 0.22);
        }
        .video-frame {
            position: relative;
            width: 100%;
            aspect-ratio: 16 / 9;
            background: #0a0a0e;
            border-radius: 10px;
            overflow: hidden;
            border: 1px solid rgba(255, 255, 255, 0.06);
            box-shadow: inset 0 2px 12px rgba(0, 0, 0, 0.65);
        }
        .video-frame video {
            width: 100%;
            height: 100%;
            object-fit: contain;
            display: block;
        }
        .video-frame--stack {
            background: #0a0a0e;
            border: 1px solid rgba(255, 255, 255, 0.06);
            box-shadow: inset 0 2px 12px rgba(0, 0, 0, 0.65);
        }
        .video-frame--stack video {
            position: absolute;
            left: 0;
            top: 0;
            width: 100%;
            height: 100%;
            object-fit: contain;
            display: block;
        }
        .video-frame--stack .video-timecode {
            z-index: 4;
        }
        .compare-stage--composite .video-frame--stack .video-timecode {
            font-size: clamp(22px, 2.7vw, 28px);
            padding: 0.36em 0.5em;
        }
        .video-stack-top--diff {
            z-index: 2;
            mix-blend-mode: difference;
            opacity: 1;
        }
        .video-stack-top--cross {
            z-index: 2;
            mix-blend-mode: normal;
            opacity: 0.75;
        }
        .video-stack-bottom {
            z-index: 1;
        }
        .compare-composite {
            box-sizing: border-box;
        }
        .video-panel.video-panel--composite::before {
            background: linear-gradient(90deg, var(--accent-deep), var(--accent), var(--accent-deep));
            opacity: 0.92;
        }
        .compare-composite .video-panel--composite {
            border: 1px solid rgba(255, 255, 255, 0.06);
            box-shadow:
                0 14px 36px rgba(0, 0, 0, 0.42),
                inset 0 1px 0 rgba(255, 255, 255, 0.06);
        }
        .compare-composite[hidden] {
            display: none !important;
        }
        .video-timecode {
            position: absolute;
            left: 0;
            bottom: 0;
            visibility: hidden;
            z-index: 2;
            overflow: visible;
            display: inline-flex;
            align-items: center;
            justify-content: flex-start;
            font-family: 'Consolas', 'Monaco', 'Cascadia Mono', monospace;
            font-size: clamp(11px, 1.35vw, 14px);
            font-weight: 700;
            letter-spacing: 0.04em;
            color: #fff4e8;
            text-shadow:
                0 0 6px rgba(0, 0, 0, 0.95),
                0 0 3px rgba(0, 0, 0, 0.88),
                0 0 1px rgba(0, 0, 0, 1);
            line-height: 1;
            white-space: nowrap;
            width: max-content;
            max-width: max-content;
            box-sizing: border-box;
            pointer-events: none;
            user-select: none;
            padding: 0.38em 0.57em;
            border-radius: 0.43em;
            background: rgba(8, 10, 18, 0.55);
            border: 1px solid rgba(255, 255, 255, 0.12);
            touch-action: none;
        }
        .video-timecode__text {
            display: block;
            line-height: 1;
            margin: 0;
            padding: 0;
        }
        .video-timecode--hidden {
            display: none !important;
        }
        .video-timecode--draggable {
            pointer-events: auto;
            cursor: grab;
        }
        .video-timecode--dragging {
            cursor: grabbing;
        }
        .video-timecode--resizing {
            cursor: nwse-resize;
        }
        .video-timecode:not(.video-timecode--draggable) .video-timecode__resize-handle {
            display: none;
        }
        .video-timecode__resize-handle {
            position: absolute;
            right: 0;
            bottom: 0;
            width: 10px;
            height: 10px;
            z-index: 5;
            pointer-events: auto;
            cursor: nwse-resize;
            touch-action: none;
            border-radius: 0 0 6px 0;
            background: linear-gradient(
                135deg,
                transparent 0 50%,
                rgba(255, 140, 50, 0.72) 50% 100%
            );
            transition: filter 0.12s ease;
        }
        .video-timecode--draggable:hover .video-timecode__resize-handle,
        .video-timecode--resizing .video-timecode__resize-handle {
            filter: brightness(1.12);
        }
        .video-timecode--snap-x,
        .video-timecode--snap-y {
            border-color: rgba(255, 186, 110, 0.72);
            box-shadow:
                0 0 0 1px rgba(255, 186, 110, 0.35),
                0 0 10px rgba(255, 140, 50, 0.22);
        }
        .burn-in-center-guide {
            position: absolute;
            z-index: 1;
            pointer-events: none;
            background: rgba(255, 186, 110, 0.9);
            box-shadow:
                0 0 6px rgba(255, 140, 50, 0.55),
                0 0 14px rgba(255, 186, 110, 0.28);
            opacity: 0;
            visibility: hidden;
            transition: opacity 0.1s ease, visibility 0.1s ease;
        }
        .burn-in-center-guide--v {
            top: 0;
            bottom: 0;
            left: 50%;
            width: 1px;
            margin-left: -0.5px;
        }
        .burn-in-center-guide--h {
            left: 0;
            right: 0;
            top: 50%;
            height: 1px;
            margin-top: -0.5px;
        }
        .video-frame--burn-snap-x .burn-in-center-guide--v {
            opacity: 1;
            visibility: visible;
        }
        .video-frame--burn-snap-y .burn-in-center-guide--h {
            opacity: 1;
            visibility: visible;
        }
        .video-timecode--idle {
            opacity: 0.45;
        }

        .transport-bar {
            background: linear-gradient(165deg, #32323c 0%, #1f1f26 42%, #26262f 100%);
            padding: 12px 14px 14px;
            border-radius: 14px;
            margin-bottom: 14px;
            display: flex;
            flex-direction: column;
            gap: 10px;
            border: 1px solid rgba(255, 255, 255, 0.06);
            box-shadow: 0 14px 36px rgba(0, 0, 0, 0.42), inset 0 1px 0 rgba(255, 255, 255, 0.06);
        }
        .seek-container {
            display: flex;
            align-items: center;
            gap: 14px;
            flex: 1;
            min-width: 0;
            box-sizing: border-box;
            min-height: var(--transport-frame-outer-h);
            padding: var(--transport-frame-pad-y) var(--transport-frame-pad-x);
            border-radius: 10px;
            background: rgba(0, 0, 0, 0.28);
            border: var(--transport-frame-border) solid rgba(255, 255, 255, 0.05);
        }
        .transport-row-seek {
            display: flex;
            align-items: center;
            gap: 14px;
            width: 100%;
        }
        .transport-row-seek #playStopBtn {
            flex-shrink: 0;
        }
        .seek-bar-wrap {
            flex-grow: 1;
            min-width: 0;
            position: relative;
            display: flex;
            align-items: center;
            height: 22px;
        }
        .seek-bar-track-bg {
            pointer-events: none;
            position: absolute;
            left: 0;
            right: 0;
            top: 50%;
            transform: translateY(-50%);
            height: 10px;
            border-radius: 999px;
            z-index: 0;
            background: linear-gradient(90deg, var(--accent-track-1) 0%, var(--accent-track-2) 42%, var(--accent-track-3) 58%, #140805 100%);
            box-shadow:
                inset 0 2px 8px rgba(0, 0, 0, 0.86),
                inset 0 0 0 1px rgba(255, 100, 40, 0.045);
        }
        @keyframes seekBarGradientMarquee {
            0% { background-position: 100% 0; }
            100% { background-position: 0 0; }
        }
        .seek-bar-wrap--playing .seek-bar-track-bg {
            background-image: linear-gradient(
                90deg,
                var(--accent-track-1) 0%,
                var(--accent-track-2) 21%,
                var(--accent-track-3) 29%,
                #140805 42%,
                var(--accent-track-1) 50%,
                var(--accent-track-2) 71%,
                var(--accent-track-3) 79%,
                #140805 92%,
                var(--accent-track-1) 100%
            );
            background-size: 200% 100%;
            background-repeat: no-repeat;
            animation: seekBarGradientMarquee 2.6s linear infinite;
            box-shadow:
                inset 0 2px 8px rgba(0, 0, 0, 0.86),
                inset 0 0 0 1px rgba(255, 100, 40, 0.045);
        }
        #seekBar {
            position: relative;
            z-index: 1;
            width: 100%;
            height: 10px;
            margin: 0;
            cursor: pointer;
            accent-color: var(--accent);
            -webkit-appearance: none;
            appearance: none;
            background: transparent;
        }
        #seekBar:disabled {
            cursor: not-allowed;
            opacity: 0.5;
        }
        #seekBar::-webkit-slider-runnable-track {
            height: 10px;
            border-radius: 999px;
            background: transparent;
            box-shadow: none;
        }
        #seekBar::-webkit-slider-thumb {
            -webkit-appearance: none;
            appearance: none;
            width: 18px;
            height: 12px;
            margin-top: -1px;
            border-radius: 5px;
            background: linear-gradient(180deg, #fff0e6 0%, #e8a878 42%, #a85a20 100%);
            border: 1px solid rgba(100, 48, 18, 0.88);
            box-shadow:
                inset 0 1px 0 rgba(255, 255, 255, 0.45),
                inset 0 -1px 0 rgba(0, 0, 0, 0.22),
                0 1px 2px rgba(0, 0, 0, 0.45);
        }
        #seekBar:focus-visible {
            outline: none;
        }
        #seekBar:focus-visible::-webkit-slider-thumb {
            box-shadow:
                inset 0 1px 0 rgba(255, 255, 255, 0.45),
                inset 0 -1px 0 rgba(0, 0, 0, 0.22),
                0 0 0 2px var(--accent-glow),
                0 1px 2px rgba(0, 0, 0, 0.45);
        }
        #seekBar::-moz-range-track {
            height: 10px;
            border-radius: 999px;
            background: transparent;
            box-shadow: none;
        }
        #seekBar::-moz-range-thumb {
            width: 18px;
            height: 12px;
            border-radius: 5px;
            border: 1px solid rgba(100, 48, 18, 0.88);
            background: linear-gradient(180deg, #fff0e6 0%, #e8a878 50%, #a85a20 100%);
            box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.4), 0 1px 2px rgba(0, 0, 0, 0.45);
        }
        #seekBar:focus-visible::-moz-range-thumb {
            box-shadow:
                inset 0 1px 0 rgba(255, 255, 255, 0.4),
                0 0 0 2px var(--accent-glow),
                0 1px 2px rgba(0, 0, 0, 0.45);
        }
        .time-display {
            box-sizing: border-box;
            display: inline-flex;
            align-items: center;
            justify-content: center;
            flex-shrink: 0;
            height: var(--transport-seek-align-h);
            min-height: var(--transport-seek-align-h);
            max-height: var(--transport-seek-align-h);
            padding: 0 10px;
            border-radius: 8px;
            background: rgba(8, 10, 18, 0.55);
            border: 1px solid rgba(255, 255, 255, 0.1);
            font-family: 'Consolas', 'Monaco', 'Cascadia Mono', monospace;
            font-size: 12px;
            line-height: 1;
            min-width: 132px;
            text-align: center;
            color: var(--app-accent);
            font-weight: 700;
            letter-spacing: 0.02em;
        }
        .timecode-row {
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            justify-content: center;
            gap: 10px 16px;
            font-family: 'Consolas', 'Monaco', 'Cascadia Mono', monospace;
            font-size: 12px;
            line-height: 1.35;
            color: #aeb6ca;
            padding: 2px 4px 0;
        }
        .timecode-row .tc-side {
            color: #c8d4e8;
            font-weight: 600;
            font-size: inherit;
        }
        .timecode-row .tc-val {
            color: var(--app-accent);
            font-weight: 700;
            letter-spacing: 0.02em;
            font-size: inherit;
        }
        .timecode-row .tc-drift-ok {
            color: #7fff9a;
            font-size: inherit;
        }
        .timecode-row .tc-drift-warn {
            color: #ffeb3b;
            font-size: inherit;
        }
        .timecode-row .tc-drift-bad {
            color: #ff3333;
            font-size: inherit;
        }
        .timecode-row .tc-drift-suf {
            color: #aeb6ca;
            font-weight: 600;
            font-size: inherit;
        }
        .timecode-row .tc-drift-num {
            font-variant-numeric: tabular-nums;
            font-family: 'Consolas', 'Monaco', 'Cascadia Mono', monospace;
            letter-spacing: 0.06em;
            font-size: inherit;
        }
        #driftRow.timecode-row {
            font-size: 14px;
        }
        #playStopBtn {
            box-sizing: border-box;
            -webkit-appearance: none;
            appearance: none;
            margin: 0;
            display: inline-flex;
            align-items: center;
            justify-content: center;
            width: 5.25rem;
            min-width: 5.25rem;
            max-width: 5.25rem;
            height: var(--transport-seek-align-h);
            min-height: var(--transport-seek-align-h);
            max-height: var(--transport-seek-align-h);
            padding-block: 0;
            padding-inline: 8px;
            line-height: 1;
            background: linear-gradient(180deg, #ff9f40 0%, var(--accent-mid) 45%, #b85a10 100%);
            color: #fff;
            border: 1px solid var(--accent-border);
            border-radius: 8px;
            font-size: 0.75em;
            font-weight: 700;
            letter-spacing: 0.05em;
            white-space: nowrap;
            text-align: center;
            cursor: pointer;
            box-shadow: 0 4px 14px rgba(200, 90, 0, 0.35), inset 0 1px 0 rgba(255, 255, 255, 0.22);
            transition: background 0.2s, border-color 0.2s, box-shadow 0.2s, filter 0.2s;
        }
        #playStopBtn:hover:not(:disabled) {
            filter: brightness(1.08);
        }
        #playStopBtn:disabled {
            opacity: 0.45;
            cursor: not-allowed;
            filter: grayscale(0.35);
            box-shadow: none;
        }
        #playStopBtn.transport-toggle--stop {
            background: linear-gradient(180deg, #e02030 0%, #9a1020 100%);
            border-color: rgba(255, 140, 150, 0.55);
            box-shadow: 0 4px 16px rgba(180, 20, 40, 0.38), inset 0 1px 0 rgba(255, 255, 255, 0.18);
        }
        #playStopBtn.transport-toggle--stop:hover:not(:disabled) {
            filter: brightness(1.1);
        }

        /** キーボード / シークバー操作のフィードバック（中央フラッシュ） */
        .seek-flash-overlay {
            position: fixed;
            inset: 0;
            display: flex;
            align-items: center;
            justify-content: center;
            z-index: 10000;
            pointer-events: none;
            opacity: 0;
            visibility: hidden;
            transition:
                opacity 0.82s ease-out,
                visibility 0s linear 0.82s;
        }
        .seek-flash-overlay.seek-flash--visible {
            opacity: 1;
            visibility: visible;
            transition: opacity 0.2s ease-out, visibility 0s;
        }
        .seek-flash-overlay__box {
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            gap: 0.12em;
            box-sizing: border-box;
            padding: 0.45em 0.8em 0.52em;
            background: rgba(255, 255, 255, 0.52);
            backdrop-filter: blur(10px);
            -webkit-backdrop-filter: blur(10px);
            color: rgba(22, 24, 32, 0.88);
            font-family: system-ui, -apple-system, 'Segoe UI', 'Hiragino Sans', sans-serif;
            font-size: clamp(0.88rem, 2.8vmin, 1.28rem);
            font-weight: 600;
            letter-spacing: 0.04em;
            line-height: 1.2;
            border-radius: 10px;
            box-shadow: 0 4px 22px rgba(0, 0, 0, 0.14);
            border: 1px solid rgba(255, 255, 255, 0.45);
            text-align: center;
            max-width: min(88vw, 18em);
        }
        .seek-flash-overlay__primary {
            font-size: 1.08em;
            font-weight: 600;
            color: rgba(18, 20, 28, 0.92);
        }
        .seek-flash-overlay__secondary {
            font-size: 0.74em;
            font-weight: 600;
            letter-spacing: 0.07em;
            color: rgba(32, 34, 44, 0.85);
        }
        .seek-flash-overlay__secondary[hidden] {
            display: none !important;
        }

        .export-blocking-overlay {
            position: fixed;
            inset: 0;
            z-index: 20000;
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 24px;
            box-sizing: border-box;
            background: rgba(6, 8, 12, 0.78);
            backdrop-filter: blur(5px);
            -webkit-backdrop-filter: blur(5px);
            pointer-events: auto;
            cursor: default;
        }
        .export-blocking-overlay[hidden] {
            display: none !important;
        }
        .export-blocking-overlay__panel {
            max-width: 28rem;
            text-align: center;
            padding: 28px 32px 30px;
            border-radius: 14px;
            background: linear-gradient(165deg, #2e2e38 0%, #1c1c24 100%);
            border: 1px solid rgba(255, 255, 255, 0.1);
            box-shadow: 0 20px 60px rgba(0, 0, 0, 0.55), inset 0 1px 0 rgba(255, 255, 255, 0.06);
        }
        .export-blocking-overlay__title {
            margin: 0 0 10px;
            font-size: 1.15rem;
            font-weight: 800;
            letter-spacing: 0.06em;
            color: #f4f6fc;
        }
        .export-blocking-overlay__sub {
            margin: 0;
            font-size: 0.9rem;
            font-weight: 600;
            letter-spacing: 0.04em;
            color: #b8c4dc;
            font-variant-numeric: tabular-nums;
        }
        .export-blocking-overlay__esc-hint {
            margin: 0 0 12px;
            font-size: 0.88rem;
            font-weight: 600;
            line-height: 1.45;
            letter-spacing: 0.03em;
            color: #c8d4ec;
        }
        .export-blocking-overlay__esc-hint kbd {
            display: inline-block;
            padding: 0.1em 0.45em;
            border-radius: 4px;
            border: 1px solid rgba(255, 255, 255, 0.18);
            background: rgba(0, 0, 0, 0.28);
            font-family: inherit;
            font-size: 0.95em;
            font-weight: 700;
        }

        .solo-tc-notice-overlay {
            z-index: 19500;
        }
        .solo-tc-notice-overlay .solo-tc-notice-body {
            white-space: pre-line;
            text-align: left;
            line-height: 1.55;
            max-width: 26rem;
            margin-left: auto;
            margin-right: auto;
        }
        .solo-tc-notice-ok-btn {
            box-sizing: border-box;
            -webkit-appearance: none;
            appearance: none;
            margin: 1.15rem 0 0;
            padding: 0.42rem 1.35rem;
            min-width: 5.5rem;
            border-radius: 8px;
            border: 1px solid rgba(255, 255, 255, 0.16);
            background: linear-gradient(180deg, #4a5060 0%, #353842 48%, #282a34 100%);
            color: #e8ecf4;
            font-size: 0.82rem;
            font-weight: 700;
            letter-spacing: 0.06em;
            cursor: pointer;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.35), inset 0 1px 0 rgba(255, 255, 255, 0.1);
        }
        .solo-tc-notice-ok-btn:hover {
            filter: brightness(1.06);
        }
        .solo-tc-notice-ok-btn:focus-visible {
            outline: 2px solid var(--accent-glow);
            outline-offset: 2px;
        }

        .transport-options-rows {
            display: flex;
            flex-direction: column;
            align-items: stretch;
            gap: 8px;
            width: 100%;
        }
        .transport-options-strip {
            display: flex;
            flex-wrap: wrap;
            align-items: stretch;
            justify-content: center;
            gap: 10px 12px;
            width: 100%;
            padding: 0;
            border: none;
            background: transparent;
            box-sizing: border-box;
        }
        .transport-options-strip--secondary {
            justify-content: center;
        }
        .transport-opt-box {
            display: flex;
            align-items: center;
            flex: 0 1 auto;
            width: fit-content;
            max-width: 100%;
            min-width: 0;
            min-height: var(--transport-opt-box-min-h);
            box-sizing: border-box;
            padding: var(--transport-frame-pad-y) calc(var(--transport-frame-pad-x) + 4px);
            border-radius: 999px;
            background: rgba(0, 0, 0, 0.28);
            border: var(--transport-frame-border) solid rgba(255, 255, 255, 0.08);
            font-size: var(--transport-opt-font-size);
            transition: border-color 0.35s ease-out, box-shadow 0.35s ease-out;
        }
        @keyframes transportOptGlowPulse {
            0% {
                border-color: rgba(255, 255, 255, 0.08);
                box-shadow: 0 0 0 0 rgba(255, 120, 40, 0);
            }
            28% {
                border-color: rgba(255, 170, 90, 0.55);
                box-shadow:
                    0 0 0 1px rgba(255, 140, 60, 0.4),
                    0 0 16px rgba(255, 130, 40, 0.55),
                    0 0 28px rgba(255, 95, 20, 0.38);
            }
            100% {
                border-color: rgba(255, 255, 255, 0.08);
                box-shadow: 0 0 0 0 rgba(255, 120, 40, 0);
            }
        }
        .transport-opt-box.transport-opt-box--glow {
            animation: transportOptGlowPulse 0.88s ease-out forwards;
        }
        .export-pip-btn {
            box-sizing: border-box;
            -webkit-appearance: none;
            appearance: none;
            margin: 0;
            display: inline-flex;
            align-items: center;
            justify-content: center;
            min-width: 4.75rem;
            height: var(--transport-opt-control-h);
            min-height: var(--transport-opt-control-h);
            max-height: var(--transport-opt-control-h);
            padding: 0 10px;
            line-height: 1;
            background: linear-gradient(180deg, #e82838 0%, #b01020 48%, #7a0814 100%);
            color: #fff;
            border: 1px solid rgba(255, 140, 150, 0.55);
            border-radius: 8px;
            font-size: 0.72rem;
            font-weight: 800;
            letter-spacing: 0.03em;
            white-space: nowrap;
            cursor: pointer;
            box-shadow: 0 4px 14px rgba(180, 20, 40, 0.38), inset 0 1px 0 rgba(255, 255, 255, 0.18);
            transition: background 0.2s, border-color 0.2s, box-shadow 0.2s, filter 0.2s;
        }
        .export-pip-btn:hover:not(:disabled) {
            filter: brightness(1.08);
        }
        .export-pip-btn:disabled {
            opacity: 0.48;
            cursor: not-allowed;
            filter: brightness(0.82) saturate(0.75);
            box-shadow: none;
        }
        .transport-opt-cell--export {
            flex-direction: row;
            flex-wrap: nowrap;
            align-items: center;
            align-self: center;
            gap: 6px 8px;
            min-width: 0;
            max-width: 100%;
        }
        .transport-opt-cell--export .transport-select--export {
            flex: 0 1 auto;
            min-width: 0;
            max-width: 8.5rem;
            padding: 0 8px;
            font-size: 0.72rem;
        }
        .transport-opt-cell--export .transport-compact-lbl--export-burn span {
            letter-spacing: 0.04em;
        }
        .transport-opt-box--export {
            min-width: 0;
            max-width: 100%;
            overflow-x: auto;
            -webkit-overflow-scrolling: touch;
        }

        .transport-opt-cell {
            display: flex;
            align-items: center;
            align-self: stretch;
            gap: 8px;
            min-width: 0;
            min-height: 0;
            flex: 0 1 auto;
        }
        .transport-opt-cell--view {
            flex: 0 1 auto;
            min-width: 0;
            max-width: 100%;
        }
        .transport-opt-cell--loop,
        .transport-opt-cell--playback {
            flex-wrap: wrap;
            gap: 6px 10px;
        }
        .transport-opt-cell--speed {
            flex-wrap: nowrap;
            gap: 8px;
        }
        .transport-speed-stepper {
            display: inline-flex;
            align-items: center;
            gap: 4px;
        }
        .transport-speed-btn {
            box-sizing: border-box;
            -webkit-appearance: none;
            appearance: none;
            margin: 0;
            display: inline-flex;
            align-items: center;
            justify-content: center;
            width: var(--transport-opt-control-h);
            min-width: var(--transport-opt-control-h);
            height: var(--transport-opt-control-h);
            min-height: var(--transport-opt-control-h);
            max-height: var(--transport-opt-control-h);
            padding: 0;
            border-radius: 999px;
            border: 1px solid rgba(255, 255, 255, 0.14);
            background: rgba(12, 14, 22, 0.92);
            color: var(--accent-ink);
            font-size: 1rem;
            font-weight: 700;
            line-height: 1;
            cursor: pointer;
        }
        .transport-speed-btn:hover:not(:disabled) {
            border-color: rgba(255, 170, 90, 0.45);
            background: rgba(28, 32, 48, 0.98);
        }
        .transport-speed-btn:disabled {
            opacity: 0.42;
            cursor: not-allowed;
        }
        .transport-speed-btn:focus-visible {
            outline: 2px solid var(--accent-glow);
            outline-offset: 1px;
        }
        .transport-speed-display {
            display: inline-block;
            min-width: 3.25rem;
            padding: 0 4px;
            text-align: center;
            font-size: var(--transport-opt-font-size);
            font-weight: 700;
            font-variant-numeric: tabular-nums;
            letter-spacing: 0.02em;
            color: var(--accent-ink);
            line-height: var(--transport-opt-control-h);
        }
        .transport-compact-lbl {
            flex-shrink: 0;
            font-size: var(--transport-opt-font-size);
            font-weight: 500;
            letter-spacing: 0.06em;
            color: #9aa6bc;
            white-space: nowrap;
        }
        label[for="viewModeSelect"].transport-compact-lbl,
        #audioModeLegend.transport-compact-lbl,
        #exportPipLegend.transport-compact-lbl,
        #playbackSpeedLegend.transport-compact-lbl {
            color: #f0f0f5;
        }
        .transport-compact-lbl--row {
            display: inline-flex;
            align-items: center;
            gap: 7px;
            min-height: var(--transport-opt-control-h);
            cursor: pointer;
            font-size: var(--transport-opt-font-size);
            font-weight: 500;
            letter-spacing: 0.04em;
            color: #d8e0f0;
        }
        .transport-compact-lbl--row input {
            margin: 0;
            flex-shrink: 0;
        }
        .transport-select {
            flex: 0 1 auto;
            min-width: 0;
            max-width: min(100%, 20rem);
            box-sizing: border-box;
            height: var(--transport-opt-control-h);
            min-height: var(--transport-opt-control-h);
            margin: 0;
            padding: 0 10px;
            border-radius: 999px;
            border: 1px solid rgba(255, 255, 255, 0.12);
            background: rgba(12, 14, 22, 0.92);
            color: var(--accent-ink);
            font-size: var(--transport-opt-font-size);
            font-weight: 500;
            line-height: var(--transport-opt-control-h);
            cursor: pointer;
            vertical-align: middle;
        }
        .transport-select option {
            color: var(--accent-ink);
            background: #14141a;
        }
        .transport-select:focus {
            outline: 2px solid var(--accent-glow);
            outline-offset: 1px;
        }
        input[type="radio"],
        input[type="checkbox"] {
            accent-color: var(--accent);
        }
        .transport-opt-cell--audio {
            display: flex;
            flex-direction: row;
            align-items: center;
            flex-wrap: wrap;
            gap: 8px 10px;
            flex: 1 1 auto;
            min-width: 0;
            max-width: 100%;
        }
        .transport-opt-cell--audio .transport-compact-lbl {
            flex-shrink: 0;
        }
        .transport-audio-inline {
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            justify-content: flex-start;
            gap: 6px 10px;
            flex: 1 1 auto;
            min-width: 0;
            row-gap: 6px;
        }
        .transport-audio-inline label {
            display: inline-flex;
            align-items: center;
            gap: 5px;
            min-height: var(--transport-opt-control-h);
            font-size: var(--transport-opt-font-size);
            font-weight: 500;
            line-height: 1.25;
            color: #d0d8e8;
            cursor: pointer;
            white-space: nowrap;
        }
        .transport-audio-inline input {
            margin: 0;
            flex-shrink: 0;
        }

        .app-doc-fold {
            margin-top: 16px;
            margin-left: auto;
            margin-right: auto;
            max-width: 1300px;
            width: 100%;
            box-sizing: border-box;
            border-radius: 14px;
            border: 1px solid rgba(255, 255, 255, 0.06);
            box-shadow: 0 8px 28px rgba(0, 0, 0, 0.35), inset 0 1px 0 rgba(255, 255, 255, 0.06);
            background: linear-gradient(165deg, #32323c 0%, #1f1f26 42%, #26262f 100%);
            overflow: hidden;
        }
        .app-doc-fold:not([open]) > .app-doc-fold__summary {
            border-radius: 13px;
        }
        .app-doc-fold__summary {
            margin: 0;
            padding: 14px 18px;
            cursor: pointer;
            list-style: none;
            font-size: 0.95rem;
            font-weight: 700;
            letter-spacing: 0.02em;
            color: #e8ecf2;
            background: linear-gradient(165deg, #3a3c44 0%, #2a2c32 45%, #22242a 100%);
            outline: none;
            border-bottom: 1px solid transparent;
        }
        .app-doc-fold[open] > .app-doc-fold__summary {
            border-bottom-color: rgba(0, 0, 0, 0.38);
        }
        .app-doc-fold__summary::-webkit-details-marker {
            display: none;
        }
        .app-doc-fold__body {
            margin: 10px 12px 14px;
            padding: 14px 16px 16px;
            border: 1px solid #4a4d52;
            border-radius: 10px;
            background: #242629;
            box-shadow: inset 0 0 18px rgba(0, 0, 0, 0.55);
            color: var(--app-doc-text);
            font-size: 0.82rem;
            line-height: 1.5;
        }
        .app-doc-fold__body > p {
            margin: 0 0 0.75em;
        }
        .app-doc-fold__body > p:last-child {
            margin-bottom: 0;
        }
        .app-manual {
            margin-top: 0;
            padding: 0;
            background: transparent;
            border-radius: 0;
            border: none;
            box-shadow: none;
            color: inherit;
            font-size: inherit;
            line-height: inherit;
        }
        .app-manual h3 {
            margin: 0 0 10px;
            font-size: 0.95rem;
            font-weight: 700;
            color: var(--app-accent);
            letter-spacing: 0.02em;
        }
        .app-manual h3:not(:first-of-type) {
            margin-top: 1.15rem;
        }
        .app-manual ul {
            margin: 0;
            padding-left: 1.25rem;
            list-style-position: outside;
            list-style-type: disc;
        }
        .app-manual ol {
            margin: 0;
            padding-left: 1.25rem;
            list-style-position: outside;
            list-style-type: decimal;
        }
        .app-manual li {
            margin-bottom: 0.45em;
        }
        .app-manual li:last-child {
            margin-bottom: 0;
        }

        .app-manual h4 {
            margin: 1.1rem 0 0.5rem;
            font-size: 0.88rem;
            font-weight: 700;
            color: var(--app-accent);
        }
        .app-manual h4:first-of-type {
            margin-top: 0.85rem;
        }

        .app-manual-category + .app-manual-category {
            margin-top: 1rem;
        }
        .app-manual-category h4 {
            margin: 0 0 0.45rem;
            font-size: 0.88rem;
            font-weight: 700;
            letter-spacing: 0.02em;
            color: var(--app-accent);
        }
        .app-manual-category ul {
            margin: 0;
        }
        .app-manual-category li {
            margin-bottom: 0.45em;
        }
        .app-manual-category li:last-child {
            margin-bottom: 0;
        }
        .app-manual code {
            font-size: 0.92em;
            color: inherit;
        }
        .app-doc-fold__body a,
        .app-manual a {
            color: var(--app-accent);
            text-decoration: none;
        }
        .app-doc-fold__body a:hover,
        .app-manual a:hover {
            text-decoration: underline;
        }

        .app-site-footer {
            margin-top: 22px;
            margin-bottom: 10px;
            padding: 12px 14px 14px;
            text-align: center;
            max-width: 52rem;
            margin-left: auto;
            margin-right: auto;
            color: #8a92a4;
            font-size: 0.78rem;
            line-height: 1.65;
        }
        .app-site-footer__copyright {
            margin: 0;
            font-size: 0.82rem;
            color: #9aa4b8;
            font-weight: 600;
        }
        .app-site-footer__copyright a {
            color: var(--app-accent);
            text-decoration: none;
        }
        .app-site-footer__copyright a:hover {
            text-decoration: underline;
        }

        .bottom-info {
            display: flex;
            gap: 15px;
            margin-top: 15px;
            align-items: stretch;
            width: 100%;
        }
        #log {
            flex: 1 1 50%;
            min-width: 0;
            max-width: none;
            box-sizing: border-box;
            min-height: 120px;
            resize: none;
            overflow-x: hidden;
            overflow-y: scroll;
            flex-shrink: 0;
            background: #242629;
            color: #f0f0f5;
            padding: 10px;
            font-family: 'Courier New', Courier, monospace;
            font-size: 11px;
            scrollbar-gutter: stable;
            scrollbar-width: thin;
            scrollbar-color: rgba(200, 210, 230, 0.45) rgba(0, 0, 0, 0.35);
            border-radius: 4px;
            border: 1px solid #4a4d52;
            box-shadow: inset 0 0 16px rgba(0, 0, 0, 0.55);
        }
        #log::-webkit-scrollbar {
            width: 10px;
        }
        #log::-webkit-scrollbar-track {
            background: rgba(0, 0, 0, 0.35);
            border-radius: 4px;
        }
        #log::-webkit-scrollbar-thumb {
            background: rgba(200, 210, 230, 0.38);
            border-radius: 5px;
            border: 2px solid transparent;
            background-clip: padding-box;
        }
        #log::-webkit-scrollbar-thumb:hover {
            background: rgba(220, 228, 245, 0.5);
            background-clip: padding-box;
        }
        .shortcut-guide {
            flex: 1 1 50%;
            min-width: 0;
            overflow-x: hidden;
            background: linear-gradient(165deg, #32323c 0%, #1f1f26 42%, #26262f 100%);
            border-radius: 14px;
            padding: 14px 16px 22px;
            border: 1px solid rgba(255, 255, 255, 0.06);
            box-shadow: 0 8px 28px rgba(0, 0, 0, 0.35), inset 0 1px 0 rgba(255, 255, 255, 0.06);
            font-family: 'Consolas', 'Courier New', Courier, monospace;
            font-size: 11px;
            color: var(--app-shortcut-text);
            line-height: 1.5;
        }
        .shortcut-sheet {
            display: grid;
            grid-template-columns: max-content minmax(0, 1fr);
            column-gap: 12px;
            align-items: start;
        }
        .shortcut-sheet__cat {
            padding: 9px 0;
            border-bottom: 1px solid rgba(255, 255, 255, 0.07);
            font-weight: 700;
            line-height: 1.45;
            white-space: nowrap;
            color: var(--app-shortcut-col1);
        }
        .shortcut-sheet__items {
            padding: 9px 0;
            border-bottom: 1px solid rgba(255, 255, 255, 0.07);
            min-width: 0;
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            gap: 5px 12px;
            line-height: 1.45;
        }
        .shortcut-sheet > .shortcut-sheet__cat:nth-last-child(2),
        .shortcut-sheet > .shortcut-sheet__items:last-child {
            border-bottom: none;
            padding-bottom: 0;
        }
        .shortcut-sheet__chip {
            white-space: nowrap;
            font-size: 10.5px;
            letter-spacing: 0.01em;
        }
        .shortcut-guide__title {
            color: var(--app-shortcut-heading);
            display: block;
            margin-bottom: 12px;
            font-size: 12px;
            font-weight: 500;
            letter-spacing: 0.02em;
        }
        @media (max-width: 900px) {
            .bottom-info {
                flex-direction: column;
            }
            #log {
                flex: 1 1 auto;
                max-width: none;
                width: 100%;
            }
            .shortcut-guide {
                flex: 1 1 auto;
                width: 100%;
            }
        }