/* ─── Variables ──────────────────────────────────────────────────────────── */
:root {
    --bg-page: #f0f2f5;
    --bg-card: #ffffff;
    --bg-nav: #ffffff;
    --accent: #58a6ff;
    --accent-hover: #4393e6;
    --accent-light: #e8f1fc;
    --text-primary: #1a1a2e;
    --text-secondary: #5a6072;
    --text-muted: #8b8fa3;
    --border: #e2e5ea;
    --success: #2da44e;
    --success-bg: #dafbe1;
    --danger: #cf222e;
    --radius: 12px;
    --radius-sm: 8px;
    --shadow: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
    --shadow-lg: 0 4px 16px rgba(0,0,0,0.08);
}

/* ─── Dark Theme ─────────────────────────────────────────────────────────── */
[data-theme="dark"] {
    --bg-page: #0d1117;
    --bg-card: #161b22;
    --bg-nav: #161b22;
    --accent: #58a6ff;
    --accent-hover: #79b8ff;
    --accent-light: #1a2332;
    --text-primary: #e6edf3;
    --text-secondary: #8b949e;
    --text-muted: #6e7681;
    --border: #30363d;
    --success: #3fb950;
    --success-bg: #1a2e1f;
    --danger: #f85149;
    --shadow: 0 1px 3px rgba(0,0,0,0.3), 0 1px 2px rgba(0,0,0,0.2);
    --shadow-lg: 0 4px 16px rgba(0,0,0,0.4);
}
[data-theme="dark"] .navbar-toggler-icon {
    filter: invert(1);
}
[data-theme="dark"] .accordion-button::after {
    filter: invert(1);
}
[data-theme="dark"] .form-control,
[data-theme="dark"] .form-select {
    background-color: var(--bg-card);
    color: var(--text-primary);
    border-color: var(--border);
}
[data-theme="dark"] .alert {
    border-color: var(--border);
}

/* ─── Theme Toggle Button ────────────────────────────────────────────────── */
.theme-toggle {
    border: none;
    background: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 0.4rem;
    font-size: 1.1rem;
    line-height: 1;
    border-radius: 6px;
    transition: color 0.15s;
}
.theme-toggle:hover {
    color: var(--text-primary);
}

/* ─── Base ───────────────────────────────────────────────────────────────── */
body {
    background: var(--bg-page);
    color: var(--text-primary);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    min-height: 100vh;
}

/* ─── Navbar ─────────────────────────────────────────────────────────────── */
.navbar {
    background: var(--bg-nav);
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow);
    padding: 0.5rem 0;
}
.navbar-brand {
    font-size: 1.25rem;
    color: var(--text-primary) !important;
}
.navbar-brand img {
    border-radius: 4px;
}
.nav-link {
    color: var(--text-secondary) !important;
    font-weight: 500;
    font-size: 0.925rem;
}
.nav-link:hover {
    color: var(--text-primary) !important;
}
.dropdown-menu-tools {
    min-width: 240px;
    border: 1px solid var(--border);
    box-shadow: var(--shadow-lg);
    border-radius: var(--radius-sm);
}
.dropdown-header {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    font-weight: 600;
}

/* ─── Hero (Homepage) ────────────────────────────────────────────────────── */
.hero {
    text-align: center;
    padding: 3.5rem 1rem 2rem;
}
.hero h1 {
    font-size: 2.5rem;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 0.75rem;
}
.hero p {
    color: var(--text-secondary);
    font-size: 1.1rem;
    max-width: 520px;
    margin: 0 auto;
}
.search-box {
    max-width: 480px;
    margin: 1.5rem auto 0;
}
.search-box input {
    border: 1px solid var(--border);
    border-radius: 50px;
    padding: 0.75rem 1.25rem 0.75rem 2.75rem;
    font-size: 1rem;
    background: var(--bg-card);
    width: 100%;
    box-shadow: var(--shadow);
}
.search-box input:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(88,166,255,0.15);
}
.search-box .search-icon {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    font-size: 1.1rem;
}

/* ─── Category Cards (Homepage) ──────────────────────────────────────────── */
.category-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1.25rem;
    padding: 1rem 0 3rem;
}
.category-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
}
.category-card h2 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}
.category-card h2 i {
    font-size: 1.25rem;
}
.tool-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}
.tool-tag {
    display: inline-block;
    padding: 0.35rem 0.85rem;
    border-radius: 50px;
    font-size: 0.85rem;
    font-weight: 500;
    text-decoration: none;
    background: var(--accent-light);
    color: var(--accent);
    border: 1px solid transparent;
    transition: all 0.15s;
}
.tool-tag:hover {
    background: var(--accent);
    color: #fff;
    text-decoration: none;
}
.tool-tag-empty {
    background: #f5f5f5;
    color: var(--text-muted);
    cursor: default;
}
.tool-tag-empty:hover {
    background: #f5f5f5;
    color: var(--text-muted);
}

/* ─── Tool Page Layout ───────────────────────────────────────────────────── */
.tool-page {
    max-width: 720px;
    margin: 0 auto;
    padding: 2rem 1rem 3rem;
}
.tool-page h1 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 0.25rem;
}
.tool-page .tool-desc {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

/* ─── Upload Zone ────────────────────────────────────────────────────────── */
.upload-zone {
    background: var(--bg-card);
    border: 2px dashed var(--border);
    border-radius: var(--radius);
    padding: 2.5rem 1.5rem;
    text-align: center;
    cursor: pointer;
    transition: border-color 0.2s, background 0.2s;
    position: relative;
}
.upload-zone:hover,
.upload-zone.drag-over {
    border-color: var(--accent);
    background: var(--accent-light);
}
.upload-zone .upload-icon {
    font-size: 2.5rem;
    color: var(--text-muted);
    margin-bottom: 0.5rem;
}
.upload-zone p {
    margin: 0;
    color: var(--text-secondary);
}
.upload-zone .accepted-label {
    font-size: 0.825rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
}
.no-storage-badge {
    position: absolute;
    top: 1rem;
    right: 1rem;
    font-size: 0.7rem;
    color: var(--text-muted);
    line-height: 1.3;
    text-align: right;
}

/* ─── File List (multi-file) ─────────────────────────────────────────────── */
.file-list {
    margin-top: 1rem;
}
.file-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.6rem 0.75rem;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    margin-bottom: 0.5rem;
}
.file-item .file-icon {
    color: var(--accent);
    font-size: 1.25rem;
}
.file-item .file-info {
    flex: 1;
    min-width: 0;
}
.file-item .file-name {
    font-weight: 500;
    font-size: 0.9rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}
.file-item .file-size {
    font-size: 0.8rem;
    color: var(--text-muted);
}
.file-item .file-actions {
    display: flex;
    gap: 0.25rem;
}
.file-item .file-actions button {
    border: none;
    background: none;
    color: var(--text-muted);
    padding: 0.25rem;
    cursor: pointer;
    border-radius: 4px;
}
.file-item .file-actions button:hover {
    background: var(--bg-page);
    color: var(--text-primary);
}
.add-more-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.4rem 0.8rem;
    border: 1px dashed var(--border);
    border-radius: var(--radius-sm);
    background: none;
    color: var(--accent);
    font-size: 0.85rem;
    cursor: pointer;
    margin-top: 0.25rem;
}
.add-more-btn:hover {
    border-color: var(--accent);
    background: var(--accent-light);
}

/* ─── Options Panel ──────────────────────────────────────────────────────── */
.options-panel {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.25rem;
    margin-top: 1rem;
}
.options-panel .option-row {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
}
.options-panel label {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    white-space: nowrap;
}
.options-panel select,
.options-panel input[type="number"],
.options-panel input[type="text"] {
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 0.4rem 0.6rem;
    font-size: 0.9rem;
    background: var(--bg-card);
}
.options-panel select:focus,
.options-panel input:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 2px rgba(88,166,255,0.15);
}
.options-panel input[type="range"] {
    flex: 1;
    min-width: 100px;
    accent-color: var(--accent);
}
.range-value {
    font-size: 0.9rem;
    font-weight: 600;
    min-width: 2.5rem;
    text-align: center;
}

/* ─── Action Button ──────────────────────────────────────────────────────── */
.action-btn {
    display: block;
    width: 100%;
    padding: 0.85rem;
    margin-top: 1rem;
    border: none;
    border-radius: var(--radius);
    background: var(--accent);
    color: #fff;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.15s;
}
.action-btn:hover:not(:disabled) {
    background: var(--accent-hover);
}
.action-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* ─── Progress Bar ───────────────────────────────────────────────────────── */
.progress-section {
    display: none;
    margin-top: 1rem;
}
.progress-section.active {
    display: block;
}
.progress {
    height: 8px;
    border-radius: 4px;
    background: var(--bg-page);
    overflow: hidden;
}
.progress-bar {
    background: var(--accent);
    transition: width 0.2s;
}
.progress-label {
    font-size: 0.825rem;
    color: var(--text-muted);
    margin-top: 0.4rem;
    text-align: center;
}

/* ─── Result Section ─────────────────────────────────────────────────────── */
.result-section {
    display: none;
    margin-top: 1rem;
}
.result-section.active {
    display: block;
}
.result-card {
    background: var(--success-bg);
    border: 1px solid #aceebb;
    border-radius: var(--radius);
    padding: 1.25rem;
    text-align: center;
}
.result-card .result-icon {
    font-size: 2rem;
    color: var(--success);
}
.result-card .result-title {
    font-weight: 600;
    font-size: 1.1rem;
    margin: 0.5rem 0 0.25rem;
}
.result-card .result-sizes {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 0.75rem;
}
.result-card .result-sizes .savings {
    color: var(--success);
    font-weight: 600;
}
.download-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.7rem 1.75rem;
    border: none;
    border-radius: var(--radius);
    background: var(--success);
    color: #fff;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    text-decoration: none;
    transition: background 0.15s;
}
.download-btn:hover {
    background: #238b3e;
    color: #fff;
}

/* ─── Error Section ──────────────────────────────────────────────────────── */
.error-section {
    display: none;
    margin-top: 1rem;
}
.error-section.active {
    display: block;
}
.error-card {
    background: #fff5f5;
    border: 1px solid #fcc;
    border-radius: var(--radius);
    padding: 1rem 1.25rem;
    color: var(--danger);
    font-size: 0.925rem;
}

/* ─── SEO Content Block ──────────────────────────────────────────────────── */
.seo-content {
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border);
}
.seo-content h2 {
    font-size: 1.35rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}
.seo-content p {
    color: var(--text-secondary);
    line-height: 1.65;
    margin-bottom: 1.5rem;
}

/* FAQ Accordion */
.faq-section {
    margin-top: 2rem;
}
.faq-section h2 {
    font-size: 1.35rem;
    font-weight: 600;
    margin-bottom: 1rem;
}
.accordion-item {
    border: 1px solid var(--border);
    border-radius: var(--radius-sm) !important;
    margin-bottom: 0.5rem;
    overflow: hidden;
}
.accordion-button {
    font-weight: 500;
    font-size: 0.95rem;
    background: var(--bg-card);
    color: var(--text-primary);
}
.accordion-button:not(.collapsed) {
    background: var(--bg-card);
    color: var(--accent);
    box-shadow: none;
}
.accordion-button:focus {
    box-shadow: none;
    border-color: var(--border);
}
.accordion-body {
    color: var(--text-secondary);
    font-size: 0.925rem;
    line-height: 1.6;
}

/* ─── Related Tools ──────────────────────────────────────────────────────── */
.related-tools {
    margin-top: 2.5rem;
}
.related-tools h2 {
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: 1rem;
}
.related-tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    gap: 0.75rem;
}
.related-tool-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 1rem;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    text-decoration: none;
    color: var(--text-primary);
    transition: border-color 0.15s, box-shadow 0.15s;
    text-align: center;
}
.related-tool-card:hover {
    border-color: var(--accent);
    box-shadow: var(--shadow);
    color: var(--text-primary);
    text-decoration: none;
}
.related-tool-card i {
    font-size: 1.5rem;
    color: var(--accent);
    margin-bottom: 0.5rem;
}
.related-tool-card span {
    font-size: 0.85rem;
    font-weight: 500;
}

/* ─── Footer ─────────────────────────────────────────────────────────────── */
footer {
    border-top: 1px solid var(--border);
    background: var(--bg-card);
}
.footer-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
}
.footer-link:hover {
    color: var(--text-primary);
}

/* ─── Responsive ─────────────────────────────────────────────────────────── */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 1.75rem;
    }
    .category-grid {
        grid-template-columns: 1fr;
    }
    .tool-page {
        padding: 1.5rem 1rem 2rem;
    }
    .options-panel .option-row {
        flex-direction: column;
        align-items: stretch;
    }
}