:root {
    --bg: #0f0f13;
    --surface: #17171e;
    --card: #1e1e28;
    --border: #2a2a38;
    --text: #e8e8f0;
    --muted: #7a7a96;
    --accent-simple: #4ade80;
    --accent-cont: #60a5fa;
    --accent-perf: #f472b6;
    --accent-perfcont: #fb923c;
    --accent-simple-dim: rgba(74,222,128,0.12);
    --accent-cont-dim: rgba(96,165,250,0.12);
    --accent-perf-dim: rgba(244,114,182,0.12);
    --accent-perfcont-dim: rgba(251,146,60,0.12);
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body {
    background: var(--bg);
    color: var(--text);
    font-family: 'IBM Plex Sans', sans-serif;
    min-height: 100vh;
    padding: 24px 16px 60px;
}
header {
    text-align: center;
    padding: 40px 0 32px;
    border-bottom: 1px solid var(--border);
    margin-bottom: 36px;
}
header h1 {
    font-family: 'Playfair Display', serif;
    font-size: clamp(28px, 6vw, 48px);
    font-weight: 900;
    letter-spacing: -1px;
    background: linear-gradient(135deg, #e8e8f0 30%, #7a7a96);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 10px;
}
header p {
    color: var(--muted);
    font-size: 14px;
    letter-spacing: 0.5px;
}

/* TIMELINE GRID */
.overview {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 24px;
    margin-bottom: 40px;
    overflow-x: auto;
}
.overview h2 {
    font-family: 'Playfair Display', serif;
    font-size: 18px;
    margin-bottom: 20px;
    color: var(--muted);
    text-transform: uppercase;
    letter-spacing: 2px;
    font-size: 11px;
}
.grid-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 13px;
    min-width: 520px;
}
.grid-table th {
    padding: 10px 14px;
    text-align: center;
    font-family: 'IBM Plex Mono', monospace;
    font-size: 11px;
    letter-spacing: 1px;
    color: var(--muted);
    border-bottom: 1px solid var(--border);
}
.grid-table td {
    padding: 10px 14px;
    text-align: center;
    border-bottom: 1px solid rgba(42,42,56,0.5);
    font-size: 12px;
    line-height: 1.5;
}
.grid-table tr:last-child td { border-bottom: none; }
.row-label {
    text-align: left !important;
    font-family: 'IBM Plex Mono', monospace;
    font-size: 11px;
    color: var(--muted);
    letter-spacing: 0.5px;
    white-space: nowrap;
}
.cell-simple { color: var(--accent-simple); }
.cell-cont { color: var(--accent-cont); }
.cell-perf { color: var(--accent-perf); }
.cell-perfcont { color: var(--accent-perfcont); }

/* TABS */
.tabs {
    display: flex;
    gap: 8px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}
.tab {
    padding: 8px 16px;
    border-radius: 20px;
    border: 1px solid var(--border);
    background: var(--card);
    color: var(--muted);
    font-size: 13px;
    font-family: 'IBM Plex Sans', sans-serif;
    cursor: pointer;
    transition: all 0.2s;
    font-weight: 500;
}
.tab:hover { border-color: var(--muted); color: var(--text); }
.tab.active-simple { border-color: var(--accent-simple); color: var(--accent-simple); background: var(--accent-simple-dim); }
.tab.active-cont { border-color: var(--accent-cont); color: var(--accent-cont); background: var(--accent-cont-dim); }
.tab.active-perf { border-color: var(--accent-perf); color: var(--accent-perf); background: var(--accent-perf-dim); }
.tab.active-perfcont { border-color: var(--accent-perfcont); color: var(--accent-perfcont); background: var(--accent-perfcont-dim); }

/* GROUPS */
.group { display: none; }
.group.visible { display: block; }

.group-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 24px;
}
.group-dot {
    width: 10px; height: 10px;
    border-radius: 50%;
    flex-shrink: 0;
}
.group-title {
    font-family: 'Playfair Display', serif;
    font-size: 22px;
    font-weight: 700;
}
.group-desc {
    color: var(--muted);
    font-size: 13px;
    margin-left: auto;
    font-family: 'IBM Plex Mono', monospace;
}

/* TENSE CARD */
.tense-cards {
    display: flex;
    flex-direction: column;
    gap: 20px;
}
.tense-card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 12px;
    overflow: hidden;
}
.tense-card-head {
    padding: 16px 20px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    flex-wrap: wrap;
}
.tense-name {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 15px;
    font-weight: 600;
}
.tense-ru {
    font-size: 12px;
    color: var(--muted);
}
.formula-badge {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 12px;
    padding: 4px 10px;
    border-radius: 6px;
    border: 1px solid;
    white-space: nowrap;
}
.tense-card-body {
    padding: 20px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}
@media (max-width: 600px) {
    .tense-card-body { grid-template-columns: 1fr; }
}
.section-label {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 10px;
    letter-spacing: 1.5px;
    text-transform: uppercase;
    color: var(--muted);
    margin-bottom: 10px;
}

/* USAGE */
.usage-list { list-style: none; padding: 0; }
.usage-list li {
    font-size: 13px;
    padding: 5px 0;
    padding-left: 14px;
    position: relative;
    color: #c8c8e0;
    line-height: 1.5;
    border-bottom: 1px solid rgba(42,42,56,0.4);
}
.usage-list li:last-child { border-bottom: none; }
.usage-list li::before {
    content: '→';
    position: absolute;
    left: 0;
    color: var(--muted);
    font-size: 11px;
    top: 6px;
}

/* EXAMPLES */
.example {
    margin-bottom: 12px;
}
.example:last-child { margin-bottom: 0; }
.example-en {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 13px;
    margin-bottom: 3px;
    line-height: 1.5;
}
.example-en strong {
    font-weight: 600;
}
.example-ru {
    font-size: 12px;
    color: var(--muted);
    font-style: italic;
}

/* SIGNAL WORDS */
.signals {
    margin-top: 16px;
    padding-top: 16px;
    border-top: 1px solid var(--border);
    grid-column: 1 / -1;
}
.signal-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-top: 8px;
}
.signal-tag {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 11px;
    padding: 3px 9px;
    border-radius: 4px;
    background: var(--surface);
    border: 1px solid var(--border);
    color: #a0a0be;
}

/* COLORS PER GROUP */
.simple .tense-name { color: var(--accent-simple); }
.simple .formula-badge { color: var(--accent-simple); border-color: rgba(74,222,128,0.3); background: var(--accent-simple-dim); }
.cont .tense-name { color: var(--accent-cont); }
.cont .formula-badge { color: var(--accent-cont); border-color: rgba(96,165,250,0.3); background: var(--accent-cont-dim); }
.perf .tense-name { color: var(--accent-perf); }
.perf .formula-badge { color: var(--accent-perf); border-color: rgba(244,114,182,0.3); background: var(--accent-perf-dim); }
.perfcont .tense-name { color: var(--accent-perfcont); }
.perfcont .formula-badge { color: var(--accent-perfcont); border-color: rgba(251,146,60,0.3); background: var(--accent-perfcont-dim); }

.accent-simple { color: var(--accent-simple) }
.accent-cont { color: var(--accent-cont) }
.accent-perf { color: var(--accent-perf) }
.accent-perfcont { color: var(--accent-perfcont) }

/* NEGATION / QUESTION SECTION */
.forms-section {
    grid-column: 1 / -1;
    margin-top: 4px;
}
.forms-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
    margin-top: 8px;
}
.form-block {
    background: var(--surface);
    border-radius: 8px;
    padding: 10px 12px;
    border: 1px solid var(--border);
}
.form-type {
    font-size: 10px;
    font-family: 'IBM Plex Mono', monospace;
    letter-spacing: 1px;
    color: var(--muted);
    margin-bottom: 6px;
    text-transform: uppercase;
}
.form-example {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 12px;
    color: #c8c8e0;
    line-height: 1.6;
}