/* ═══════════════════════════════════════════════════════════════════════════
   VaultDL - Dark Editorial SaaS-Grade Design System
   Inspired by Linear.app and Vercel
   ═══════════════════════════════════════════════════════════════════════════ */

:root {
    --bg-primary: #0a0a0a;
    --bg-surface: #111111;
    --bg-elevated: #1a1a1a;
    --border: #2a2a2a;
    --border-active: #3a3a3a;
    --text-primary: #f0f0f0;
    --text-secondary: #888888;
    --text-muted: #444444;
    --accent: #e8ff47;
    --accent-dim: #b8cc30;
    --accent-light: #f0ff99;
    --danger: #ff4444;
    --danger-light: #ff6666;
    --success: #44ff88;
    --success-light: #66ff99;
    
    --font-display: 'Syne', sans-serif;
    --font-body: 'IBM Plex Mono', monospace;
    
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-fast: all 0.15s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-smooth: all 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html, body {
    width: 100%;
    height: 100%;
}

body {
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-family: var(--font-body);
    font-size: 14px;
    line-height: 1.6;
    letter-spacing: 0.5px;
    overflow-x: hidden;
    scroll-behavior: smooth;
}

/* ───────────────────────────────────────────────────────────────────────── */
/* Tooltips */
/* ───────────────────────────────────────────────────────────────────────── */

button[title],
input[title],
div[title] {
    position: relative;
}

button[title]:hover::after,
input[title]:hover::after,
div[title]:hover::after {
    content: attr(title);
    position: absolute;
    bottom: 120%;
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--accent);
    color: #000;
    padding: 0.5rem 0.75rem;
    border-radius: 6px;
    white-space: nowrap;
    font-size: 0.75rem;
    font-weight: 600;
    z-index: 1000;
    pointer-events: none;
    animation: tooltipFadeIn 0.3s ease;
}

button[title]:hover::before,
input[title]:hover::before,
div[title]:hover::before {
    content: '';
    position: absolute;
    bottom: 115%;
    left: 50%;
    transform: translateX(-50%);
    border: 5px solid transparent;
    border-top-color: var(--accent);
    z-index: 1000;
    pointer-events: none;
}

@keyframes tooltipFadeIn {
    from {
        opacity: 0;
        transform: translateX(-50%) translateY(5px);
    }
    to {
        opacity: 1;
        transform: translateX(-50%) translateY(0);
    }
}

/* ───────────────────────────────────────────────────────────────────────── */
/* Header */
/* ───────────────────────────────────────────────────────────────────────── */

.header {
    padding: 4rem 1rem 3rem;
    text-align: center;
    border-bottom: 1px solid var(--border);
    background: linear-gradient(to bottom, var(--bg-surface), var(--bg-primary));
    position: relative;
    overflow: hidden;
}

.header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(to right, transparent, var(--accent), transparent);
    opacity: 0.3;
}

.header-content {
    max-width: 640px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

.logo-container {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1.5rem;
    margin-bottom: 1rem;
}

.logo-decoration {
    width: 30px;
    height: 2px;
    background: linear-gradient(to right, transparent, var(--accent), transparent);
    opacity: 0.4;
}

.logo {
    font-family: var(--font-display);
    font-size: 2.8rem;
    font-weight: 800;
    letter-spacing: -0.05em;
    text-transform: uppercase;
    animation: fadeInDown 0.8s ease;
}

.logo-text {
    color: var(--text-primary);
}

.logo-accent {
    color: var(--accent);
    text-shadow: 0 0 20px rgba(232, 255, 71, 0.3);
}

.subtitle {
    font-size: 0.95rem;
    color: var(--text-secondary);
    font-weight: 400;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    margin-bottom: 0.75rem;
    animation: fadeInUp 0.8s ease 0.1s both;
}

.header-hint {
    font-size: 0.8rem;
    color: var(--text-muted);
    letter-spacing: 0.08em;
    animation: fadeInUp 0.8s ease 0.2s both;
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-15px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ───────────────────────────────────────────────────────────────────────── */
/* Container & Card */
/* ───────────────────────────────────────────────────────────────────────── */

.container {
    max-width: 640px;
    margin: 0 auto;
    padding: 2.5rem 1rem;
    min-height: calc(100vh - 200px);
    display: flex;
    align-items: flex-start;
    justify-content: center;
}

.card {
    width: 100%;
    background-color: var(--bg-surface);
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 2.5rem;
    transition: var(--transition);
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
    position: relative;
    overflow: hidden;
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(to right, transparent, var(--accent), transparent);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.card:hover {
    border-color: var(--border-active);
    box-shadow: 0 15px 50px rgba(232, 255, 71, 0.08);
}

.card:hover::before {
    opacity: 0.3;
}

/* ───────────────────────────────────────────────────────────────────────── */
/* Form Elements */
/* ───────────────────────────────────────────────────────────────────────── */

.form-group {
    margin-bottom: 2rem;
}

.input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
}

.url-input {
    width: 100%;
    padding: 1rem 1.25rem;
    padding-right: 3.5rem;
    background-color: var(--bg-elevated);
    border: 1.5px solid var(--border);
    border-radius: 8px;
    color: var(--text-primary);
    font-family: var(--font-body);
    font-size: 0.95rem;
    letter-spacing: 0.4px;
    transition: var(--transition-fast);
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.2);
}

.url-input::placeholder {
    color: var(--text-muted);
}

.url-input:hover {
    border-color: var(--border-active);
}

.url-input:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(232, 255, 71, 0.15), inset 0 2px 4px rgba(0, 0, 0, 0.2);
    background-color: var(--bg-elevated);
}

.paste-btn {
    position: absolute;
    right: 0.75rem;
    padding: 0.6rem 0.8rem;
    background-color: transparent;
    border: 1px solid var(--border);
    border-radius: 6px;
    font-size: 1.1rem;
    cursor: pointer;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-secondary);
}

.paste-btn:hover {
    border-color: var(--accent);
    background-color: rgba(232, 255, 71, 0.1);
    color: var(--accent);
    transform: scale(1.1);
}

.paste-btn:active {
    transform: scale(0.95);
}

.error-message {
    margin-top: 0.75rem;
    color: var(--danger);
    font-size: 0.85rem;
    min-height: 1.2rem;
    animation: slideDown 0.3s ease;
}

/* ───────────────────────────────────────────────────────────────────────── */
/* Toggle Group */
/* ───────────────────────────────────────────────────────────────────────── */

.toggle-group {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    margin-bottom: 2rem;
}

.toggle-btn {
    padding: 0.95rem 1.25rem;
    background-color: var(--bg-elevated);
    border: 1.5px solid var(--border);
    border-radius: 8px;
    color: var(--text-secondary);
    font-family: var(--font-display);
    font-size: 0.95rem;
    font-weight: 600;
    letter-spacing: 0.08em;
    cursor: pointer;
    transition: var(--transition-smooth);
    text-transform: uppercase;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    position: relative;
    overflow: hidden;
}

.toggle-btn::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, transparent, rgba(255, 255, 255, 0.1), transparent);
    opacity: 0;
    transition: opacity 0.3s ease;
    pointer-events: none;
}

.toggle-btn:hover {
    border-color: var(--border-active);
    color: var(--text-primary);
}

.toggle-btn.active {
    background: linear-gradient(135deg, var(--accent), var(--accent-dim));
    border-color: var(--accent);
    color: #000;
    box-shadow: 0 4px 16px rgba(232, 255, 71, 0.25), inset 0 1px 0 rgba(255, 255, 255, 0.15);
    transform: translateY(-2px);
}

.toggle-btn.active::before {
    opacity: 1;
}

.toggle-icon {
    font-size: 1.2rem;
}

/* ───────────────────────────────────────────────────────────────────────── */
/* Quality Selection */
/* ───────────────────────────────────────────────────────────────────────── */

.quality-section {
    margin-bottom: 2rem;
    max-height: 0;
    opacity: 0;
    overflow: hidden;
    transition: all 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.quality-section.active {
    max-height: 500px;
    opacity: 1;
}

.quality-label {
    font-size: 0.8rem;
    color: var(--text-secondary);
    font-weight: 700;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.quality-label::before {
    content: '';
    width: 3px;
    height: 3px;
    background-color: var(--accent);
    border-radius: 50%;
}

.quality-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.quality-btn {
    padding: 0.75rem 0.875rem;
    background-color: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: 6px;
    color: var(--text-secondary);
    font-family: var(--font-body);
    font-size: 0.8rem;
    font-weight: 500;
    letter-spacing: 0.4px;
    cursor: pointer;
    transition: var(--transition-smooth);
    text-transform: uppercase;
    position: relative;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.35rem;
}

.quality-btn:hover {
    border-color: var(--border-active);
    color: var(--accent);
    background-color: rgba(232, 255, 71, 0.05);
}

.quality-btn.active {
    background: linear-gradient(135deg, var(--accent), var(--accent-dim));
    border-color: var(--accent);
    color: #000;
    font-weight: 600;
    box-shadow: 0 4px 12px rgba(232, 255, 71, 0.2);
    transform: scale(1.05);
}

.badge {
    display: inline-block;
    background-color: rgba(232, 255, 71, 0.2);
    color: var(--accent);
    font-size: 0.65rem;
    padding: 0.25rem 0.5rem;
    border-radius: 3px;
    font-weight: 700;
    letter-spacing: 0.08em;
    animation: badgePulse 3s ease-in-out infinite;
    white-space: nowrap;
}

@keyframes badgePulse {
    0%, 100% { opacity: 0.7; transform: scale(1); }
    50% { opacity: 1; transform: scale(1.05); }
}

.quality-note {
    font-size: 0.85rem;
    color: var(--text-muted);
    line-height: 1.6;
    background-color: rgba(232, 255, 71, 0.03);
    padding: 0.75rem 1rem;
    border-radius: 6px;
    border-left: 2px solid var(--accent);
}

/* ───────────────────────────────────────────────────────────────────────── */
/* Download Button */
/* ───────────────────────────────────────────────────────────────────────── */

.download-btn {
    width: 100%;
    padding: 1.1rem;
    background: linear-gradient(135deg, var(--accent), var(--accent-dim));
    border: none;
    border-radius: 8px;
    color: #000;
    font-family: var(--font-display);
    font-size: 0.95rem;
    font-weight: 700;
    letter-spacing: 0.12em;
    cursor: pointer;
    transition: var(--transition-smooth);
    text-transform: uppercase;
    box-shadow: 0 6px 20px rgba(232, 255, 71, 0.25), inset 0 1px 0 rgba(255, 255, 255, 0.2);
    position: relative;
    overflow: hidden;
}

.download-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    transition: left 0.5s ease;
}

.download-btn:hover::before {
    left: 100%;
}

.download-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 12px 32px rgba(232, 255, 71, 0.35), inset 0 1px 0 rgba(255, 255, 255, 0.2);
}

.download-btn:active {
    transform: translateY(-1px);
}

.download-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

/* ───────────────────────────────────────────────────────────────────────── */
/* Progress Card */
/* ───────────────────────────────────────────────────────────────────────── */

.progress-card {
    animation: slideDown 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.progress-header {
    margin-bottom: 2rem;
    text-align: center;
}

.phase-label {
    font-family: var(--font-display);
    font-size: 1rem;
    font-weight: 700;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--accent);
    text-shadow: 0 0 15px rgba(232, 255, 71, 0.2);
    animation: fadeIn 0.6s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

/* ───────────────────────────────────────────────────────────────────────── */
/* Progress Bar */
/* ───────────────────────────────────────────────────────────────────────── */

.progress-container {
    margin-bottom: 2rem;
}

.progress-bar {
    height: 8px;
    background-color: var(--bg-elevated);
    border-radius: 4px;
    overflow: hidden;
    position: relative;
    border: 1px solid var(--border);
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.3);
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--accent), var(--success), var(--accent));
    background-size: 200% 100%;
    border-radius: 4px;
    width: 0%;
    transition: width 0.6s cubic-bezier(0.34, 1.56, 0.64, 1);
    position: relative;
    box-shadow: 0 0 16px rgba(232, 255, 71, 0.5), inset 0 1px 0 rgba(255, 255, 255, 0.3);
}

.progress-fill::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.4), transparent);
    animation: shimmer 2.5s infinite;
}

@keyframes shimmer {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(100%); }
}

/* ───────────────────────────────────────────────────────────────────────── */
/* Merge Spinner */
/* ───────────────────────────────────────────────────────────────────────── */

.merge-spinner {
    text-align: center;
    margin-bottom: 2rem;
    animation: fadeIn 0.4s ease;
}

.merge-spinner.hidden {
    display: none;
}

.spinner {
    width: 48px;
    height: 48px;
    margin: 0 auto 1.5rem;
    border: 3px solid var(--bg-elevated);
    border-top-color: var(--accent);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    box-shadow: 0 0 20px rgba(232, 255, 71, 0.3);
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.merge-spinner p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 500;
}

/* ───────────────────────────────────────────────────────────────────────── */
/* Stats Pills */
/* ───────────────────────────────────────────────────────────────────────── */

.stats-row {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.stat-pill {
    background: linear-gradient(135deg, var(--bg-elevated), rgba(232, 255, 71, 0.05));
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 0.875rem;
    text-align: center;
    font-size: 0.85rem;
    color: var(--accent);
    font-weight: 600;
    letter-spacing: 0.4px;
    transition: var(--transition-fast);
    box-shadow: 0 2px 8px rgba(232, 255, 71, 0.1);
}

.stat-pill:hover {
    border-color: var(--accent);
    box-shadow: 0 4px 12px rgba(232, 255, 71, 0.2);
    transform: translateY(-2px);
}

.filesize-line {
    color: var(--text-secondary);
    font-size: 0.85rem;
    text-align: center;
    padding: 0.75rem;
    background-color: rgba(232, 255, 71, 0.03);
    border-radius: 6px;
    border-left: 2px solid var(--accent);
}

/* ───────────────────────────────────────────────────────────────────────── */
/* Done Card */
/* ───────────────────────────────────────────────────────────────────────── */

.done-card {
    animation: slideDown 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
    text-align: center;
}

.done-header {
    margin-bottom: 2.5rem;
}

.checkmark {
    width: 100px;
    height: 100px;
    margin: 0 auto 2rem;
    display: block;
    filter: drop-shadow(0 4px 12px rgba(68, 255, 136, 0.3));
}

.checkmark-circle {
    stroke: var(--success);
    stroke-dasharray: 166;
    stroke-dashoffset: 166;
    animation: checkmarkCircle 0.8s ease-in-out forwards;
}

.checkmark-path {
    stroke: var(--success);
    stroke-dasharray: 48;
    stroke-dashoffset: 48;
    animation: checkmarkPath 0.8s ease-in-out 0.4s forwards;
    filter: drop-shadow(0 2px 4px rgba(68, 255, 136, 0.4));
}

@keyframes checkmarkCircle {
    to {
        stroke-dashoffset: 0;
    }
}

@keyframes checkmarkPath {
    to {
        stroke-dashoffset: 0;
    }
}

.done-header h2 {
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 700;
    color: var(--success);
    text-shadow: 0 0 20px rgba(68, 255, 136, 0.2);
}

.done-details {
    margin-bottom: 2.5rem;
}

.filename-badge {
    display: inline-block;
    background: linear-gradient(135deg, var(--bg-elevated), rgba(232, 255, 71, 0.05));
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1rem 1.5rem;
    margin-bottom: 1rem;
    font-size: 0.9rem;
    color: var(--accent);
    font-weight: 500;
    word-break: break-all;
    max-width: 100%;
    box-shadow: 0 4px 12px rgba(232, 255, 71, 0.1);
}

.filesize-text {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.done-actions {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 1rem;
}

.start-over-btn {
    padding: 1.1rem;
    background-color: transparent;
    border: 1.5px solid var(--border);
    border-radius: 8px;
    color: var(--text-secondary);
    font-family: var(--font-display);
    font-size: 0.95rem;
    font-weight: 700;
    letter-spacing: 0.1em;
    cursor: pointer;
    transition: var(--transition-smooth);
    text-transform: uppercase;
    position: relative;
    overflow: hidden;
}

.start-over-btn::before {
    content: '';
    position: absolute;
    inset: 0;
    background-color: var(--bg-elevated);
    opacity: 0;
    transition: opacity 0.3s ease;
    z-index: -1;
}

.start-over-btn:hover {
    border-color: var(--accent);
    color: var(--accent);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(232, 255, 71, 0.15);
}

.start-over-btn:hover::before {
    opacity: 1;
}

/* ───────────────────────────────────────────────────────────────────────── */
/* Error Card */
/* ───────────────────────────────────────────────────────────────────────── */

.error-card {
    animation: slideDown 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
    text-align: center;
}

.error-header {
    margin-bottom: 2rem;
}

.error-icon {
    font-size: 4rem;
    display: block;
    margin-bottom: 1.5rem;
    animation: shake 0.5s ease;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    10%, 30%, 50%, 70%, 90% { transform: translateX(-5px); }
    20%, 40%, 60%, 80% { transform: translateX(5px); }
}

.error-header h2 {
    font-family: var(--font-display);
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--danger);
    text-shadow: 0 0 15px rgba(255, 68, 68, 0.2);
}

.error-detail {
    background: linear-gradient(135deg, rgba(255, 68, 68, 0.05), rgba(255, 68, 68, 0.02));
    border: 1.5px solid rgba(255, 68, 68, 0.2);
    border-radius: 8px;
    padding: 1.25rem;
    margin-bottom: 2rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.7;
    word-break: break-word;
}

/* ───────────────────────────────────────────────────────────────────────── */
/* Hidden State */
/* ───────────────────────────────────────────────────────────────────────── */

.hidden {
    display: none !important;
}

/* ───────────────────────────────────────────────────────────────────────── */
/* Responsive Design */
/* ───────────────────────────────────────────────────────────────────────── */

@media (max-width: 768px) {
    .header {
        padding: 3rem 1rem 2.5rem;
    }

    .logo {
        font-size: 2.2rem;
    }

    .container {
        padding: 1.5rem 0.75rem;
    }

    .card {
        padding: 1.75rem 1.25rem;
        border-radius: 8px;
    }

    .input-wrapper {
        gap: 0.5rem;
    }

    .paste-btn {
        right: 0.5rem;
        padding: 0.5rem 0.6rem;
    }

    .quality-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 0.6rem;
    }

    .quality-btn {
        padding: 0.65rem 0.6rem;
        font-size: 0.75rem;
    }

    .done-actions {
        grid-template-columns: 1fr;
    }

    .stats-row {
        grid-template-columns: 1fr;
    }

    button[title]:hover::after,
    input[title]:hover::after,
    div[title]:hover::after {
        display: none;
    }
}

@media (max-width: 640px) {
    .header {
        padding: 2.5rem 1rem 2rem;
    }

    .logo-container {
        gap: 1rem;
    }

    .logo-decoration {
        width: 20px;
    }

    .logo {
        font-size: 2rem;
    }

    .subtitle {
        font-size: 0.85rem;
    }

    .header-hint {
        font-size: 0.75rem;
        margin-top: 0.5rem;
    }

    .container {
        padding: 1rem 0.5rem;
    }

    .card {
        padding: 1.25rem 0.875rem;
        border-radius: 8px;
        box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
    }

    .form-group {
        margin-bottom: 1.25rem;
    }

    .input-wrapper {
        gap: 0.3rem;
    }

    .url-input {
        padding: 0.8rem 3.2rem 0.8rem 0.875rem;
        font-size: 0.85rem;
    }

    .paste-btn {
        right: 0.4rem;
        padding: 0.45rem 0.5rem;
        font-size: 0.95rem;
    }

    .toggle-group {
        gap: 0.5rem;
        margin-bottom: 1.25rem;
    }

    .toggle-btn {
        padding: 0.75rem 0.875rem;
        font-size: 0.8rem;
        gap: 0.4rem;
    }

    .toggle-icon {
        font-size: 1rem;
    }

    .quality-grid {
        grid-template-columns: 1fr 1fr;
        gap: 0.4rem;
    }

    .quality-btn {
        padding: 0.55rem 0.4rem;
        font-size: 0.7rem;
    }

    .quality-label {
        font-size: 0.75rem;
        margin-bottom: 0.6rem;
    }

    .badge {
        font-size: 0.6rem;
        padding: 0.2rem 0.3rem;
        margin-left: 0.2rem;
    }

    .quality-note {
        font-size: 0.75rem;
        padding: 0.5rem 0.75rem;
        margin-bottom: 1rem;
    }

    .download-btn {
        padding: 0.95rem;
        font-size: 0.85rem;
    }

    .progress-header {
        margin-bottom: 1.5rem;
    }

    .phase-label {
        font-size: 0.9rem;
    }

    .progress-container {
        margin-bottom: 1.25rem;
    }

    .progress-bar {
        height: 6px;
    }

    .stats-row {
        grid-template-columns: 1fr;
        gap: 0.6rem;
        margin-bottom: 1rem;
    }

    .stat-pill {
        padding: 0.6rem;
        font-size: 0.75rem;
    }

    .filesize-line {
        font-size: 0.75rem;
        padding: 0.5rem 0.75rem;
    }

    .spinner {
        width: 36px;
        height: 36px;
        margin-bottom: 1rem;
    }

    .merge-spinner p {
        font-size: 0.85rem;
    }

    .checkmark {
        width: 70px;
        height: 70px;
        margin: 0 auto 1.25rem;
    }

    .done-header h2 {
        font-size: 1.35rem;
    }

    .filename-badge {
        padding: 0.6rem 0.875rem;
        font-size: 0.8rem;
        margin-bottom: 0.75rem;
    }

    .filesize-text {
        font-size: 0.85rem;
    }

    .done-actions {
        grid-template-columns: 1fr;
        gap: 0.6rem;
    }

    .download-btn,
    .start-over-btn {
        padding: 0.85rem;
        font-size: 0.8rem;
    }

    .error-icon {
        font-size: 2.5rem;
        margin-bottom: 0.875rem;
    }

    .error-header h2 {
        font-size: 1.25rem;
    }

    .error-detail {
        padding: 0.875rem;
        font-size: 0.8rem;
        margin-bottom: 1.25rem;
        line-height: 1.6;
    }
}

    .download-btn {
        padding: 0.95rem;
        font-size: 0.9rem;
    }

    .progress-container {
        margin-bottom: 1.5rem;
    }

    .progress-bar {
        height: 6px;
    }

    .stats-row {
        grid-template-columns: 1fr;
        gap: 0.75rem;
    }

    .stat-pill {
        padding: 0.75rem;
        font-size: 0.8rem;
    }

    .filesize-line {
        font-size: 0.8rem;
        padding: 0.6rem 0.8rem;
    }

    .spinner {
        width: 40px;
        height: 40px;
    }

    .merge-spinner p {
        font-size: 0.9rem;
    }

    .checkmark {
        width: 80px;
        height: 80px;
        margin: 0 auto 1.5rem;
    }

    .done-header h2 {
        font-size: 1.5rem;
    }

    .filename-badge {
        padding: 0.75rem 1rem;
        font-size: 0.85rem;
    }

    .done-actions {
        grid-template-columns: 1fr;
        gap: 0.75rem;
    }

    .done-actions .download-btn,
    .done-actions .start-over-btn {
        padding: 0.95rem;
        font-size: 0.85rem;
    }

    .error-icon {
        font-size: 3rem;
        margin-bottom: 1rem;
    }

    .error-header h2 {
        font-size: 1.35rem;
    }

    .error-detail {
        padding: 1rem;
        font-size: 0.85rem;
        margin-bottom: 1.5rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0.75rem 0.4rem;
    }

    .card {
        padding: 1rem 0.75rem;
    }

    .header {
        padding: 2rem 0.75rem 1.75rem;
    }

    .logo {
        font-size: 1.75rem;
    }

    .subtitle {
        font-size: 0.8rem;
    }

    .form-group {
        margin-bottom: 1rem;
    }

    .url-input {
        padding: 0.7rem 2.8rem 0.7rem 0.75rem;
        font-size: 0.8rem;
    }

    .toggle-btn {
        padding: 0.7rem 0.75rem;
        font-size: 0.75rem;
    }

    .quality-grid {
        gap: 0.35rem;
    }

    .quality-btn {
        padding: 0.5rem 0.35rem;
        font-size: 0.65rem;
    }

    .download-btn {
        padding: 0.9rem;
        font-size: 0.8rem;
    }

    .card h3 {
        font-size: 1rem;
    }

    .quality-label {
        font-size: 0.7rem;
    }

    .badge {
        font-size: 0.55rem;
    }

    .done-header h2 {
        font-size: 1.2rem;
    }

    .error-header h2 {
        font-size: 1.1rem;
    }
}

@media (prefers-reduced-motion: reduce) {
    * {
        animation: none !important;
        transition: none !important;
    }
}