/* Reset & base */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

/* Dark theme (default) */
:root {
    --bg: #0f1117;
    --surface: #1a1d27;
    --surface-hover: #222633;
    --border: #2a2e3d;
    --text: #e4e6ed;
    --text-muted: #8b8fa3;
    --accent: #6c63ff;
    --accent-glow: rgba(108, 99, 255, 0.15);
    --green: #22c55e;
    --blue: #3b82f6;
    --orange: #f59e0b;
    --pink: #ec4899;
    --cyan: #06b6d4;
    --radius: 12px;
}

/* Light theme */
body.light {
    --bg: #f5f6fa;
    --surface: #ffffff;
    --surface-hover: #f0f1f5;
    --border: #dcdee5;
    --text: #1a1d27;
    --text-muted: #6b7085;
    --accent: #5b54e6;
    --accent-glow: rgba(91, 84, 230, 0.1);
    --green: #16a34a;
    --blue: #2563eb;
    --orange: #d97706;
    --pink: #db2777;
    --cyan: #0891b2;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    line-height: 1.6;
    transition: background 0.25s, color 0.25s;
}

/* Loading */
.loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100vh;
    gap: 16px;
    color: var(--text-muted);
}

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border);
    border-top-color: var(--accent);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

/* Layout */
.page {
    max-width: 800px;
    margin: 0 auto;
    padding: 48px 24px;
}

/* Top bar: lang + theme toggles */
.top-bar {
    display: flex;
    justify-content: flex-end;
    align-items: center;
    gap: 12px;
    margin-bottom: 8px;
}

/* Header */
.header {
    text-align: center;
    margin-bottom: 40px;
}

.header h1 {
    font-size: 2.2rem;
    font-weight: 700;
    margin-bottom: 8px;
    background: linear-gradient(135deg, var(--accent), var(--cyan));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.header p {
    color: var(--text-muted);
    font-size: 1.05rem;
    max-width: 520px;
    margin: 0 auto;
}

/* How it works */
.how-it-works {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 6px;
    margin-bottom: 32px;
}

.algo-step {
    text-align: center;
    padding: 10px 4px;
    border-radius: var(--radius);
    background: var(--surface);
    border: 1px solid var(--border);
    transition: border-color 0.2s, background 0.2s;
}

.algo-step.active {
    border-color: var(--accent);
    background: var(--accent-glow);
}

.algo-step .step-num {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--accent);
}

.algo-step .step-label {
    font-size: 0.65rem;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    color: var(--text-muted);
    margin-top: 2px;
}

/* Search box */
.search-box {
    position: relative;
    margin-bottom: 32px;
}

.search-box input {
    width: 100%;
    padding: 16px 20px 16px 52px;
    background: var(--surface);
    border: 2px solid var(--border);
    border-radius: var(--radius);
    color: var(--text);
    font-size: 1.15rem;
    outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.search-box input:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 4px var(--accent-glow);
}

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

.search-icon {
    position: absolute;
    left: 18px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    font-size: 1.2rem;
    pointer-events: none;
}

/* Stats bar */
.stats {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px 4px;
    margin-bottom: 16px;
    color: var(--text-muted);
    font-size: 0.85rem;
}

/* Results */
.results {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.result-card {
    display: grid;
    grid-template-columns: 1fr auto auto;
    align-items: center;
    gap: 16px;
    padding: 14px 18px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    transition: background 0.15s, border-color 0.15s;
    animation: fadeIn 0.2s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(4px); }
    to { opacity: 1; transform: translateY(0); }
}

.result-card:hover {
    background: var(--surface-hover);
    border-color: var(--accent);
}

.result-name {
    font-weight: 600;
    font-size: 1rem;
}

.result-detail {
    color: var(--text-muted);
    font-size: 0.85rem;
}

/* Badge */
.badge {
    display: inline-flex;
    align-items: center;
    padding: 4px 10px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.03em;
    text-transform: uppercase;
    white-space: nowrap;
}

.badge-exact { background: rgba(34, 197, 94, 0.15); color: var(--green); }
.badge-prefix { background: rgba(59, 130, 246, 0.15); color: var(--blue); }
.badge-substring { background: rgba(6, 182, 212, 0.15); color: var(--cyan); }
.badge-similar { background: rgba(245, 158, 11, 0.15); color: var(--orange); }
.badge-phonetic { background: rgba(236, 72, 153, 0.15); color: var(--pink); }

/* Similarity bar */
.similarity {
    display: flex;
    align-items: center;
    gap: 8px;
    min-width: 100px;
}

.similarity-bar {
    flex: 1;
    height: 6px;
    background: var(--border);
    border-radius: 3px;
    overflow: hidden;
}

.similarity-fill {
    height: 100%;
    border-radius: 3px;
    transition: width 0.3s ease;
}

.similarity-value {
    font-size: 0.85rem;
    font-weight: 600;
    min-width: 38px;
    text-align: right;
    color: var(--text-muted);
}

/* Examples */
.examples {
    margin-top: 40px;
    padding-top: 32px;
    border-top: 1px solid var(--border);
}

.examples h3 {
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-muted);
    margin-bottom: 12px;
}

.example-chips {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.chip {
    padding: 6px 14px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 20px;
    font-size: 0.85rem;
    color: var(--text);
    cursor: pointer;
    transition: background 0.15s, border-color 0.15s;
}

.chip:hover {
    background: var(--surface-hover);
    border-color: var(--accent);
}

/* Empty state */
.empty-state {
    text-align: center;
    padding: 48px 0;
    color: var(--text-muted);
}

.empty-state .icon {
    font-size: 2.5rem;
    margin-bottom: 12px;
}

/* Footer */
.footer {
    text-align: center;
    margin-top: 48px;
    padding-top: 24px;
    border-top: 1px solid var(--border);
    color: var(--text-muted);
    font-size: 0.85rem;
    line-height: 1.8;
}

.footer a {
    color: var(--accent);
    text-decoration: none;
    font-weight: 500;
}

.footer a:hover {
    text-decoration: underline;
}

/* Toggle buttons (lang + theme) */
.toggle-group {
    display: flex;
    gap: 4px;
}

.toggle-btn, .toggle-active {
    padding: 4px 10px;
    border-radius: 6px;
    font-size: 0.8rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.15s;
    border: 1px solid var(--border);
}

.toggle-btn {
    background: var(--surface);
    color: var(--text-muted);
}

.toggle-btn:hover {
    background: var(--surface-hover);
}

.toggle-active {
    background: var(--accent);
    color: white;
    border-color: var(--accent);
}

/* Dataset tabs */
.dataset-tabs {
    display: flex;
    gap: 6px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.tab, .tab-active {
    padding: 8px 16px;
    border-radius: 8px;
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.15s, border-color 0.15s;
}

.tab {
    background: var(--surface);
    color: var(--text-muted);
    border: 1px solid var(--border);
}

.tab:hover {
    background: var(--surface-hover);
    border-color: var(--accent);
    color: var(--text);
}

.tab-active {
    background: var(--accent-glow);
    color: var(--accent);
    border: 1px solid var(--accent);
}

/* Responsive */
@media (max-width: 600px) {
    .header h1 { font-size: 1.6rem; }
    .result-card { grid-template-columns: 1fr; gap: 8px; }
    .similarity { justify-content: flex-start; }
    .dataset-tabs { gap: 4px; }
    .tab, .tab-active { padding: 6px 10px; font-size: 0.8rem; }
    .how-it-works { grid-template-columns: repeat(3, 1fr); }
    .algo-step .step-label { font-size: 0.6rem; }
}