/* epubkit — Clean, polished UI */

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

:root {
    --bg: #f7f7f8;
    --surface: #ffffff;
    --border: #e5e5e7;
    --border-hover: #d0d0d4;
    --text: #1d1d1f;
    --text-secondary: #6e6e73;
    --text-muted: #aeaeb2;
    --accent: #1d1d1f;
    --accent-hover: #424245;
    --success: #34c759;
    --success-bg: #ecfdf3;
    --error: #ff3b30;
    --error-bg: #fef2f2;
    --radius: 12px;
    --radius-sm: 8px;
    --shadow-sm: 0 1px 3px rgba(0,0,0,.06), 0 1px 2px rgba(0,0,0,.04);
    --shadow: 0 2px 8px rgba(0,0,0,.08), 0 1px 3px rgba(0,0,0,.06);
    --transition: 0.2s ease;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Inter', Roboto, Helvetica, Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 680px;
    margin: 0 auto;
    padding: 40px 20px 40px;
}

/* Header */
header {
    text-align: center;
    margin-bottom: 36px;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    margin-bottom: 8px;
}

.logo-icon {
    font-size: 32px;
    line-height: 1;
}

header h1 {
    font-size: 32px;
    font-weight: 700;
    letter-spacing: -0.5px;
    color: var(--text);
}

.subtitle {
    color: var(--text-secondary);
    font-size: 16px;
    font-weight: 400;
}

.subtitle-detail {
    color: var(--text-muted);
    font-size: 13px;
    margin-top: 4px;
    letter-spacing: 0.3px;
}

.section-header {
    margin-bottom: 16px;
}

h2 {
    font-size: 16px;
    font-weight: 600;
    color: var(--text);
    letter-spacing: -0.2px;
}

/* Upload Zone */
.upload-zone {
    border: 2px dashed var(--border);
    border-radius: var(--radius);
    padding: 48px 24px;
    text-align: center;
    cursor: pointer;
    transition: all var(--transition);
    background: var(--surface);
}

.upload-zone:hover {
    border-color: var(--border-hover);
    background: #fafafa;
}

.upload-zone.dragover {
    border-color: var(--accent);
    background: #f0f0f2;
    border-style: solid;
}

.upload-icon {
    width: 40px;
    height: 40px;
    color: var(--text-muted);
    margin-bottom: 16px;
}

.upload-label {
    font-size: 16px;
    font-weight: 500;
    color: var(--text-secondary);
}

.upload-hint {
    color: var(--text-muted) !important;
    font-size: 13px !important;
    font-weight: 400;
    margin-top: 4px;
}

/* File List */
.file-list {
    margin-top: 16px;
}

.file-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px;
    margin-bottom: 10px;
    display: flex;
    gap: 14px;
    align-items: flex-start;
    box-shadow: var(--shadow-sm);
    transition: box-shadow var(--transition);
}

.file-card:hover {
    box-shadow: var(--shadow);
}

.file-card.error {
    border-color: var(--error);
    background: var(--error-bg);
}

.file-cover {
    width: 52px;
    height: 72px;
    background: #f0f0f2;
    border-radius: 6px;
    overflow: hidden;
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
}

.file-cover img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.file-cover .no-cover {
    font-size: 10px;
    color: var(--text-muted);
    text-align: center;
    line-height: 1.3;
}

.file-info {
    flex: 1;
    min-width: 0;
}

.file-name {
    font-weight: 600;
    font-size: 14px;
    word-break: break-word;
    line-height: 1.3;
}

.file-meta {
    font-size: 13px;
    color: var(--text-secondary);
    margin-top: 2px;
}

.file-error {
    color: var(--error);
    font-size: 13px;
    font-weight: 500;
    margin-top: 4px;
}

.file-edit {
    margin-top: 8px;
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

.file-edit input {
    font-family: inherit;
    font-size: 13px;
    padding: 6px 10px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    flex: 1;
    min-width: 120px;
    background: var(--bg);
    color: var(--text);
    transition: border-color var(--transition);
}

.file-edit input:focus {
    outline: none;
    border-color: var(--accent);
}

.file-remove {
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    font-size: 20px;
    padding: 0 4px;
    line-height: 1;
    transition: color var(--transition);
}

.file-remove:hover {
    color: var(--error);
}

/* Options Panel */
.options-panel {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
    margin-top: 16px;
    box-shadow: var(--shadow-sm);
}

.preset-bar {
    display: flex;
    gap: 8px;
    margin-bottom: 20px;
}

.preset-btn {
    flex: 1;
    padding: 10px 8px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background: var(--surface);
    cursor: pointer;
    text-align: center;
    transition: all var(--transition);
}

.preset-btn:hover {
    border-color: var(--border-hover);
    background: var(--bg);
}

.preset-btn.active {
    background: var(--accent);
    color: #fff;
    border-color: var(--accent);
}

.preset-icon {
    display: block;
    font-size: 18px;
    margin-bottom: 2px;
}

.preset-label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    line-height: 1.3;
}

.preset-desc {
    display: block;
    font-size: 11px;
    opacity: 0.65;
    margin-top: 1px;
}

.options-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
    margin-bottom: 20px;
}

.option {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    padding: 10px 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition);
    font-size: 14px;
}

.option:hover {
    background: var(--bg);
    border-color: var(--border-hover);
}

.option input[type="checkbox"] {
    accent-color: var(--accent);
    margin-top: 2px;
    flex-shrink: 0;
}

.option-text {
    display: flex;
    flex-direction: column;
    gap: 1px;
}

.option-text span {
    font-weight: 500;
    font-size: 13px;
    line-height: 1.3;
}

.option-text small {
    font-size: 11px;
    color: var(--text-muted);
    line-height: 1.3;
}

.option-wide {
    grid-column: 1 / -1;
}

.quality-control {
    margin-bottom: 24px;
}

.quality-label {
    font-size: 13px;
    font-weight: 600;
    display: block;
    margin-bottom: 8px;
    color: var(--text);
}

.quality-presets {
    display: flex;
    gap: 6px;
    margin-bottom: 10px;
}

.quality-btn {
    flex: 1;
    padding: 6px;
    border: 1px solid var(--border);
    border-radius: 6px;
    background: var(--surface);
    cursor: pointer;
    font-size: 12px;
    font-weight: 500;
    transition: all var(--transition);
}

.quality-btn:hover {
    background: var(--bg);
    border-color: var(--border-hover);
}

.quality-btn.active {
    background: var(--accent);
    color: #fff;
    border-color: var(--accent);
}

.quality-slider-row {
    display: flex;
    align-items: center;
    gap: 12px;
}

.quality-slider-row input[type="range"] {
    flex: 1;
    accent-color: var(--accent);
    height: 4px;
}

#quality-value {
    font-size: 13px;
    font-weight: 600;
    font-variant-numeric: tabular-nums;
    min-width: 32px;
    color: var(--text-secondary);
}

.process-btn {
    width: 100%;
    padding: 14px;
    background: var(--accent);
    color: #fff;
    border: none;
    border-radius: var(--radius);
    font-family: inherit;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: background var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.process-btn:hover {
    background: var(--accent-hover);
}

.process-btn:disabled {
    background: var(--border);
    cursor: not-allowed;
}

/* Progress */
.progress-section {
    margin-top: 20px;
}

.progress-item {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px;
    margin-bottom: 10px;
    box-shadow: var(--shadow-sm);
}

.progress-item .filename {
    font-weight: 600;
    font-size: 14px;
    margin-bottom: 10px;
}

.progress-bar-container {
    background: var(--bg);
    border-radius: 6px;
    height: 6px;
    overflow: hidden;
    margin-bottom: 8px;
}

.progress-bar {
    background: var(--accent);
    height: 100%;
    border-radius: 6px;
    transition: width 0.3s ease;
    width: 0%;
}

.progress-bar.complete {
    background: var(--success);
}

.progress-bar.error {
    background: var(--error);
}

.progress-message {
    font-size: 13px;
    color: var(--text-secondary);
}

/* Results */
.results-section {
    margin-top: 20px;
}

.result-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
    margin-bottom: 10px;
    box-shadow: var(--shadow-sm);
}

.result-card.success {
    border-color: var(--success);
}

.result-card.error {
    border-color: var(--error);
}

.result-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}

.result-header .filename {
    font-weight: 600;
    font-size: 15px;
}

.result-size {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
    margin-bottom: 12px;
    flex-wrap: wrap;
}

.size-original {
    color: var(--text-muted);
    text-decoration: line-through;
}

.size-arrow {
    color: var(--text-muted);
}

.size-new {
    font-weight: 600;
    color: var(--success);
}

.size-reduction {
    background: var(--success-bg);
    color: #16a34a;
    padding: 2px 10px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
}

.result-summary {
    font-size: 13px;
    color: var(--text-secondary);
    line-height: 1.7;
    padding: 10px 14px;
    background: var(--bg);
    border-radius: var(--radius-sm);
    margin-bottom: 16px;
}

.download-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 10px 20px;
    background: var(--success);
    color: #fff;
    border: none;
    border-radius: var(--radius-sm);
    font-family: inherit;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    text-decoration: none;
    transition: background var(--transition);
}

.download-btn:hover {
    background: #2db84e;
}

.download-all-btn {
    width: 100%;
    padding: 14px;
    background: var(--success);
    color: #fff;
    border: none;
    border-radius: var(--radius);
    font-family: inherit;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    margin-top: 8px;
    transition: background var(--transition);
}

.download-all-btn:hover {
    background: #2db84e;
}

/* Footer */
footer {
    margin-top: 48px;
    padding-top: 20px;
    border-top: 1px solid var(--border);
    text-align: center;
}

footer p {
    font-size: 13px;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    flex-wrap: wrap;
}

footer a {
    color: var(--text-secondary);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 5px;
    font-weight: 500;
    transition: color var(--transition);
}

footer a:hover {
    color: var(--text);
}

.github-icon {
    vertical-align: middle;
}

.footer-sep {
    color: var(--border);
}

.footer-note {
    color: var(--text-muted);
}

/* Responsive */
@media (max-width: 600px) {
    .container {
        padding: 24px 16px 32px;
    }

    header h1 {
        font-size: 26px;
    }

    .options-grid {
        grid-template-columns: 1fr;
    }

    .option-wide {
        grid-column: 1;
    }

    .file-card {
        flex-direction: column;
    }

    .file-cover {
        width: 100%;
        height: 120px;
    }

    .preset-btn {
        padding: 8px 4px;
    }

    .preset-desc {
        display: none;
    }

    footer p {
        flex-direction: column;
        gap: 4px;
    }

    .footer-sep {
        display: none;
    }
}