/* =============================================
   iSolvIt - Topic Page Styles v2
   Place in wwwroot/css/topic.css
   ============================================= */

@import url('https://fonts.googleapis.com/css2?family=Syne:wght@400;600;700;800&family=Source+Sans+3:wght@300;400;500;600&family=STIX+Two+Text:ital,wght@0,400;0,600;0,700;1,400&display=swap');

/* ── DARK THEME (default) ─────────────────── */
:root,
[data-theme="dark"] {
    --bg: #0c0c10;
    --bg-alt: #111118;
    --surface: #16161e;
    --surface2: #1c1c26;
    --surface3: #22222e;
    --border: #2e2e3e;
    --border-bright: #3d3d52;
    --accent: #4f8eff;
    --accent-hover: #6ba3ff;
    --accent-dim: rgba(79, 142, 255, 0.12);
    --accent-border: rgba(79, 142, 255, 0.3);
    --green: #2dd87a;
    --green-dim: rgba(45, 216, 122, 0.1);
    --green-border: rgba(45, 216, 122, 0.3);
    --red: #ff5370;
    --red-dim: rgba(255, 83, 112, 0.1);
    --red-border: rgba(255, 83, 112, 0.3);
    --text: #f0f0f8;
    --text-secondary: #a8a8c0;
    --text-muted: #5e5e78;
    --tag-bg: rgba(79, 142, 255, 0.12);
    --tag-border: rgba(79, 142, 255, 0.35);
    --tag-text: #7ab0ff;
    --formula-bg: rgba(79, 142, 255, 0.08);
    --formula-border: rgba(79, 142, 255, 0.2);
    --formula-text: #90bfff;
    --result-border: #4f8eff;
    --tab-active-bg: #4f8eff;
    --tab-active-text: #ffffff;
    --toggle-bg: #1c1c26;
    --toggle-border: #2e2e3e;
}

/* ── LIGHT THEME ──────────────────────────── */
[data-theme="light"] {
    --bg: #f5f5fa;
    --bg-alt: #ededf5;
    --surface: #ffffff;
    --surface2: #f0f0f8;
    --surface3: #e8e8f2;
    --border: #d8d8e8;
    --border-bright: #c0c0d8;
    --accent: #2563eb;
    --accent-hover: #1d4ed8;
    --accent-dim: rgba(37, 99, 235, 0.08);
    --accent-border: rgba(37, 99, 235, 0.25);
    --green: #16a34a;
    --green-dim: rgba(22, 163, 74, 0.08);
    --green-border: rgba(22, 163, 74, 0.25);
    --red: #dc2626;
    --red-dim: rgba(220, 38, 38, 0.07);
    --red-border: rgba(220, 38, 38, 0.25);
    --text: #111118;
    --text-secondary: #44445a;
    --text-muted: #888899;
    --tag-bg: rgba(37, 99, 235, 0.07);
    --tag-border: rgba(37, 99, 235, 0.2);
    --tag-text: #2563eb;
    --formula-bg: rgba(37, 99, 235, 0.05);
    --formula-border: rgba(37, 99, 235, 0.18);
    --formula-text: #1d4ed8;
    --result-border: #2563eb;
    --tab-active-bg: #2563eb;
    --tab-active-text: #ffffff;
    --toggle-bg: #ffffff;
    --toggle-border: #d8d8e8;
}

/* ── RESET & BASE ─────────────────────────── */
*, *::before, *::after {
    box-sizing: border-box;
}

.isolvit-root {
    background: var(--bg);
    color: var(--text);
    font-family: 'Source Sans 3', sans-serif;
    min-height: 100vh;
    transition: background 0.25s, color 0.25s;
}

/* ── THEME TOGGLE ─────────────────────────── */
.theme-toggle {
    position: fixed;
    top: 1.25rem;
    right: 1.25rem;
    z-index: 100;
    background: var(--toggle-bg);
    border: 1px solid var(--toggle-border);
    border-radius: 999px;
    padding: 0.4rem 0.9rem;
    cursor: pointer;
    font-size: 0.85rem;
    font-family: 'Syne', sans-serif;
    font-weight: 600;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: 0.4rem;
    transition: all 0.2s;
    box-shadow: 0 2px 8px rgba(0,0,0,0.15);
}

    .theme-toggle:hover {
        border-color: var(--accent);
        color: var(--accent);
    }

/* ── PAGE LAYOUT ──────────────────────────── */
.topic-page {
    max-width: 880px;
    margin: 0 auto;
    padding: 2.5rem 1.5rem 5rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

/* ── HEADER ───────────────────────────────── */
.topic-header {
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border);
}

.topic-tag {
    display: inline-block;
    font-family: 'Syne', sans-serif;
    font-size: 0.68rem;
    font-weight: 700;
    letter-spacing: 0.13em;
    text-transform: uppercase;
    color: var(--tag-text);
    background: var(--tag-bg);
    border: 1px solid var(--tag-border);
    padding: 0.2rem 0.75rem;
    border-radius: 999px;
    margin-bottom: 0.85rem;
}

.topic-header h1 {
    font-family: 'Syne', sans-serif;
    font-size: 2.5rem;
    font-weight: 800;
    margin: 0.2rem 0 0.5rem;
    color: var(--text);
    line-height: 1.1;
}

    .topic-header h1 span {
        color: var(--accent);
    }

.topic-subtitle {
    color: var(--text-secondary);
    font-size: 1rem;
    margin: 0;
    font-weight: 400;
}

/* ── CARDS ────────────────────────────────── */
.card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 1.75rem;
    transition: background 0.25s, border-color 0.25s;
}

    .card h2 {
        font-family: 'Syne', sans-serif;
        font-size: 0.78rem;
        font-weight: 700;
        letter-spacing: 0.1em;
        text-transform: uppercase;
        color: var(--text-muted);
        margin: 0 0 1.4rem;
        display: flex;
        align-items: center;
        gap: 0.5rem;
    }

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

/* ── EXPLANATION GRID ─────────────────────── */
.explanation-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

@media (max-width: 580px) {
    .explanation-grid {
        grid-template-columns: 1fr;
    }

    .topic-header h1 {
        font-size: 1.9rem;
    }
}

.explanation-block {
    background: var(--surface2);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.25rem;
    transition: background 0.25s;
}

    .explanation-block h3 {
        font-family: 'Syne', sans-serif;
        font-size: 0.7rem;
        font-weight: 700;
        color: var(--accent);
        margin: 0 0 0.6rem;
        text-transform: uppercase;
        letter-spacing: 0.1em;
    }

    .explanation-block p {
        font-size: 0.92rem;
        color: var(--text-secondary);
        margin: 0 0 0.9rem;
        line-height: 1.65;
    }

.formula-box {
    font-family: 'STIX Two Text', 'Times New Roman', serif;
    font-size: 0.97rem;
    background: var(--formula-bg);
    border: 1px solid var(--formula-border);
    border-radius: 8px;
    padding: 0.65rem 1rem;
    color: var(--formula-text);
    margin-bottom: 1rem;
    letter-spacing: 0.02em;
}

.rules-list {
    margin: 0;
    padding: 0;
    list-style: none;
    font-size: 0.88rem;
    color: var(--text-secondary);
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

    .rules-list li {
        display: flex;
        gap: 0.6rem;
        align-items: baseline;
        padding: 0.35rem 0.65rem;
        border-radius: 6px;
        background: var(--surface3);
        font-family: 'STIX Two Text', 'Times New Roman', serif;
        font-size: 0.92rem;
        line-height: 1.4;
    }

        .rules-list li strong {
            font-family: 'Source Sans 3', sans-serif;
            font-size: 0.74rem;
            font-weight: 600;
            color: var(--text-muted);
            text-transform: uppercase;
            letter-spacing: 0.05em;
            white-space: nowrap;
            min-width: 90px;
        }

/* ── SOLVER TABS ──────────────────────────── */
.solver-tabs {
    display: flex;
    gap: 0.3rem;
    margin-bottom: 1.5rem;
    background: var(--surface2);
    padding: 0.3rem;
    border-radius: 10px;
    width: fit-content;
    border: 1px solid var(--border);
}

.tab-btn {
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-family: 'Syne', sans-serif;
    font-size: 0.82rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    padding: 0.45rem 1.2rem;
    border-radius: 7px;
    cursor: pointer;
    transition: all 0.18s;
}

    .tab-btn.active {
        background: var(--tab-active-bg);
        color: var(--tab-active-text);
        box-shadow: 0 1px 4px rgba(0,0,0,0.2);
    }

    .tab-btn:not(.active):hover {
        color: var(--text);
        background: var(--surface3);
    }

/* ── INPUTS ───────────────────────────────── */
.input-group {
    display: flex;
    align-items: flex-end;
    gap: 1rem;
    margin-bottom: 1.25rem;
    flex-wrap: wrap;
}

.input-field {
    display: flex;
    flex-direction: column;
    gap: 0.45rem;
}

    .input-field label {
        font-size: 0.72rem;
        font-weight: 600;
        color: var(--text-muted);
        text-transform: uppercase;
        letter-spacing: 0.09em;
        font-family: 'Syne', sans-serif;
    }

    .input-field input,
    .input-field select {
        background: var(--surface2);
        border: 1.5px solid var(--border);
        border-radius: 9px;
        color: var(--text);
        font-family: 'STIX Two Text', 'Times New Roman', serif;
        font-size: 1.05rem;
        padding: 0.6rem 0.9rem;
        width: 130px;
        transition: border-color 0.18s, box-shadow 0.18s;
        outline: none;
    }

        .input-field input:focus,
        .input-field select:focus {
            border-color: var(--accent);
            box-shadow: 0 0 0 3px var(--accent-dim);
        }

    .input-field select {
        font-family: 'Source Sans 3', sans-serif;
        font-size: 0.9rem;
        cursor: pointer;
    }

.input-operator {
    font-family: 'STIX Two Text', 'Times New Roman', serif;
    font-size: 1.6rem;
    color: var(--accent);
    padding-bottom: 0.3rem;
    line-height: 1;
    opacity: 0.85;
}

/* ── BUTTONS ──────────────────────────────── */
.solve-btn {
    display: block;
    width: 100%;
    background: var(--accent);
    border: none;
    border-radius: 10px;
    color: #fff;
    cursor: pointer;
    font-family: 'Syne', sans-serif;
    font-size: 0.88rem;
    font-weight: 700;
    letter-spacing: 0.07em;
    text-transform: uppercase;
    padding: 0.75rem 1.5rem;
    transition: background 0.18s, transform 0.1s, box-shadow 0.18s;
    margin-top: 0.25rem;
}

    .solve-btn:hover {
        background: var(--accent-hover);
        box-shadow: 0 4px 16px var(--accent-dim);
    }

    .solve-btn:active {
        transform: scale(0.98);
    }

.generate-btn {
    background: var(--surface2);
    border: 1.5px solid var(--border-bright);
    border-radius: 9px;
    color: var(--text);
    cursor: pointer;
    font-family: 'Syne', sans-serif;
    font-size: 0.82rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    padding: 0.6rem 1.2rem;
    transition: all 0.18s;
}

    .generate-btn:hover {
        border-color: var(--accent);
        color: var(--accent);
        background: var(--accent-dim);
    }

/* ── RESULT BOX ───────────────────────────── */
.result-box {
    margin-top: 1.25rem;
    background: var(--surface2);
    border: 1px solid var(--border);
    border-left: 3px solid var(--result-border);
    border-radius: 10px;
    padding: 1.25rem 1.4rem;
}

.result-expression {
    font-family: 'STIX Two Text', 'Times New Roman', serif;
    font-size: 1rem;
    color: var(--text-muted);
    margin-bottom: 0.2rem;
}

.result-equals {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-bottom: 0.2rem;
}

.result-value {
    font-family: 'STIX Two Text', 'Times New Roman', serif;
    font-size: 2.2rem;
    font-weight: 700;
    color: var(--accent);
    margin-bottom: 0.75rem;
    line-height: 1;
}

.result-steps {
    display: flex;
    flex-direction: column;
    gap: 0.3rem;
    border-top: 1px solid var(--border);
    padding-top: 0.75rem;
}

.step {
    font-size: 0.88rem;
    color: var(--text-secondary);
    font-family: 'STIX Two Text', 'Times New Roman', serif;
}

/* ── ERROR ────────────────────────────────── */
.error-box {
    margin-top: 1rem;
    background: var(--red-dim);
    border: 1px solid var(--red-border);
    border-radius: 9px;
    color: var(--red);
    font-size: 0.88rem;
    padding: 0.7rem 1rem;
}

/* ── EXERCISE SECTION ─────────────────────── */
.exercise-intro {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin: -0.75rem 0 1.25rem;
    line-height: 1.5;
}

.exercise-controls {
    display: flex;
    align-items: flex-end;
    gap: 1rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

    .exercise-controls .input-field select {
        width: 160px;
    }

.exercise-box {
    background: var(--surface2);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.5rem;
}

.exercise-question {
    font-family: 'STIX Two Text', 'Times New Roman', serif;
    font-size: 1.4rem;
    font-weight: 600;
    margin-bottom: 1.25rem;
    color: var(--text);
    line-height: 1.3;
}

.exercise-input-row {
    display: flex;
    gap: 0.75rem;
    align-items: center;
    flex-wrap: wrap;
}

    .exercise-input-row input {
        background: var(--surface);
        border: 1.5px solid var(--border);
        border-radius: 9px;
        color: var(--text);
        font-family: 'STIX Two Text', 'Times New Roman', serif;
        font-size: 1.05rem;
        padding: 0.6rem 0.9rem;
        width: 150px;
        outline: none;
        transition: border-color 0.18s, box-shadow 0.18s;
    }

        .exercise-input-row input:focus {
            border-color: var(--accent);
            box-shadow: 0 0 0 3px var(--accent-dim);
        }

.check-btn {
    background: transparent;
    border: 1.5px solid var(--accent);
    border-radius: 9px;
    color: var(--accent);
    cursor: pointer;
    font-family: 'Syne', sans-serif;
    font-size: 0.82rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    padding: 0.6rem 1.2rem;
    transition: all 0.18s;
}

    .check-btn:hover {
        background: var(--accent);
        color: #fff;
    }

/* ── FEEDBACK ─────────────────────────────── */
.feedback-box {
    margin-top: 1rem;
    border-radius: 9px;
    padding: 0.8rem 1rem;
    font-size: 0.92rem;
    font-weight: 500;
    font-family: 'Source Sans 3', sans-serif;
}

    .feedback-box.correct {
        background: var(--green-dim);
        border: 1px solid var(--green-border);
        color: var(--green);
    }

    .feedback-box.incorrect {
        background: var(--red-dim);
        border: 1px solid var(--red-border);
        color: var(--red);
    }

/* ── TAB HINT ─────────────────────────────── */
.tab-hint {
    font-size: 0.88rem;
    color: var(--text-muted);
    margin: -0.75rem 0 1.25rem;
    font-style: italic;
}

/* ── THREE COLUMN GRID ────────────────────── */
.explanation-grid.three-col {
    grid-template-columns: 1fr 1fr 1fr;
}

@media (max-width: 720px) {
    .explanation-grid.three-col {
        grid-template-columns: 1fr;
    }
}

/* ── SEQUENCE DISPLAY ─────────────────────── */
.seq-display {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.3rem;
    margin: 0.5rem 0 0.9rem;
}

.seq-term {
    font-family: 'STIX Two Text', 'Times New Roman', serif;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text);
    background: var(--surface3);
    border: 1px solid var(--border);
    border-radius: 7px;
    padding: 0.25rem 0.6rem;
}

    .seq-term.last {
        color: var(--accent);
        border-color: var(--accent-border);
        background: var(--accent-dim);
    }

.seq-sep {
    color: var(--text-muted);
    font-size: 0.8rem;
}

/* ── TRIANGLE RESULTS GRID ────────────────── */
.triangle-results {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.6rem;
    margin-bottom: 1rem;
}

@media (max-width: 580px) {
    .triangle-results {
        grid-template-columns: repeat(2, 1fr);
    }
}

.tri-result-item {
    background: var(--surface3);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 0.6rem 0.8rem;
    display: flex;
    flex-direction: column;
    gap: 0.2rem;
}

.tri-label {
    font-family: 'Syne', sans-serif;
    font-size: 0.68rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-muted);
}

.tri-value {
    font-family: 'STIX Two Text', 'Times New Roman', serif;
    font-size: 1.15rem;
    font-weight: 600;
    color: var(--accent);
}

/* ── DATA INPUT ROW ───────────────────────── */
.data-input-row {
    display: flex;
    gap: 1rem;
    align-items: flex-end;
    flex-wrap: wrap;
    margin-bottom: 0.25rem;
}

.data-input {
    width: 100% !important;
    font-family: 'STIX Two Text', 'Times New Roman', serif !important;
    font-size: 1rem !important;
    background: var(--surface2);
    border: 1.5px solid var(--border);
    border-radius: 9px;
    color: var(--text);
    padding: 0.6rem 0.9rem;
    outline: none;
    transition: border-color 0.18s, box-shadow 0.18s;
}

    .data-input:focus {
        border-color: var(--accent);
        box-shadow: 0 0 0 3px var(--accent-dim);
    }

/* ── STATS GRID ───────────────────────────── */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.6rem;
    margin-bottom: 0.5rem;
}

@media (max-width: 660px) {
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.stat-card {
    background: var(--surface3);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 0.6rem 0.8rem;
    display: flex;
    flex-direction: column;
    gap: 0.2rem;
}

    .stat-card.accent {
        border-color: var(--accent-border);
        background: var(--accent-dim);
    }

.stat-label {
    font-family: 'Syne', sans-serif;
    font-size: 0.66rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.07em;
    color: var(--text-muted);
}

.stat-value {
    font-family: 'STIX Two Text', 'Times New Roman', serif;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text);
}

.stat-card.accent .stat-value {
    color: var(--accent);
}

/* ── FREQUENCY TABLE ──────────────────────── */
.freq-table-wrap {
    overflow-x: auto;
    margin-top: 1.25rem;
    border-radius: 10px;
    border: 1px solid var(--border);
}

.freq-table {
    width: 100%;
    border-collapse: collapse;
    font-family: 'STIX Two Text', 'Times New Roman', serif;
    font-size: 0.95rem;
}

    .freq-table th {
        background: var(--surface2);
        color: var(--text-muted);
        font-family: 'Syne', sans-serif;
        font-size: 0.72rem;
        font-weight: 700;
        text-transform: uppercase;
        letter-spacing: 0.07em;
        padding: 0.7rem 1rem;
        text-align: center;
        border-bottom: 1px solid var(--border);
    }

    .freq-table td {
        padding: 0.6rem 1rem;
        text-align: center;
        color: var(--text-secondary);
        border-bottom: 1px solid var(--border);
    }

    .freq-table tr:last-child td {
        border-bottom: none;
    }

    .freq-table tr:hover td {
        background: var(--surface2);
    }

    .freq-table .val-cell {
        font-weight: 600;
        color: var(--text);
    }

    .freq-table .total-row td {
        font-family: 'Syne', sans-serif;
        font-size: 0.8rem;
        font-weight: 700;
        color: var(--text-muted);
        background: var(--surface2);
        border-top: 1px solid var(--border-bright);
    }

/* =============================================
   HOME PAGE
   ============================================= */

/* ── HERO ─────────────────────────────────── */
.home-hero {
    position: relative;
    min-height: 60vh;
    display: flex;
    align-items: center;
    padding: 5rem 2.5rem 4rem;
    overflow: hidden;
}

.hero-bg-grid {
    position: absolute;
    inset: 0;
    background-image: linear-gradient(var(--border) 1px, transparent 1px), linear-gradient(90deg, var(--border) 1px, transparent 1px);
    background-size: 48px 48px;
    opacity: 0.35;
    mask-image: radial-gradient(ellipse 80% 80% at 50% 0%, black 40%, transparent 100%);
}

.hero-content {
    position: relative;
    z-index: 2;
    max-width: 520px;
}

.hero-eyebrow {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-family: 'Syne', sans-serif;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--text-muted);
    margin-bottom: 1.25rem;
}

.hero-dot {
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: var(--green);
    box-shadow: 0 0 8px var(--green);
    animation: pulse-dot 2s ease-in-out infinite;
}

@keyframes pulse-dot {
    0%, 100% {
        opacity: 1;
        transform: scale(1);
    }

    50% {
        opacity: 0.5;
        transform: scale(0.8);
    }
}

.hero-title {
    font-family: 'Syne', sans-serif;
    font-size: clamp(3.5rem, 8vw, 6rem);
    font-weight: 800;
    line-height: 1;
    margin: 0 0 1.25rem;
    color: var(--text);
    letter-spacing: -0.02em;
}

.hero-i {
    color: var(--text-muted);
    font-style: italic;
}

.hero-accent {
    color: var(--accent);
}

.hero-sub {
    font-size: 1.1rem;
    color: var(--text-secondary);
    line-height: 1.7;
    margin: 0 0 2rem;
}

.hero-cta {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--accent);
    border: none;
    border-radius: 10px;
    color: #fff;
    cursor: pointer;
    font-family: 'Syne', sans-serif;
    font-size: 0.9rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    padding: 0.8rem 1.75rem;
    transition: background 0.18s, transform 0.1s, box-shadow 0.2s;
}

    .hero-cta:hover {
        background: var(--accent-hover);
        box-shadow: 0 6px 24px var(--accent-dim);
        transform: translateY(-1px);
    }

/* Floating formulas */
.hero-formula-float {
    position: absolute;
    right: 3rem;
    top: 50%;
    transform: translateY(-50%);
    display: flex;
    flex-direction: column;
    gap: 0.9rem;
    z-index: 1;
}

    .hero-formula-float span {
        font-family: 'STIX Two Text', 'Times New Roman', serif;
        font-size: 0.95rem;
        color: var(--text-muted);
        background: var(--surface);
        border: 1px solid var(--border);
        border-radius: 8px;
        padding: 0.45rem 0.9rem;
        opacity: 0.6;
        transition: opacity 0.2s;
        white-space: nowrap;
    }

        .hero-formula-float span:hover {
            opacity: 1;
        }

@media (max-width: 720px) {
    .hero-formula-float {
        display: none;
    }

    .home-hero {
        padding: 4rem 1.5rem 3rem;
        min-height: auto;
    }
}

/* ── TOPICS SECTION ───────────────────────── */
.home-section {
    padding: 0 2.5rem 4rem;
    max-width: 960px;
    margin: 0 auto;
    width: 100%;
}

@media (max-width: 720px) {
    .home-section {
        padding: 0 1.25rem 3rem;
    }
}

.section-label {
    font-family: 'Syne', sans-serif;
    font-size: 0.72rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--text-muted);
    margin-bottom: 1.25rem;
}

/* ── TOPIC CARDS GRID ─────────────────────── */
.topics-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
}

@media (max-width: 860px) {
    .topics-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 520px) {
    .topics-grid {
        grid-template-columns: 1fr;
    }
}

.topic-card {
    position: relative;
    display: flex;
    flex-direction: column;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 1.4rem;
    text-decoration: none;
    color: var(--text);
    transition: border-color 0.2s, transform 0.18s, box-shadow 0.2s, background 0.2s;
    cursor: pointer;
    overflow: hidden;
}

    .topic-card::before {
        content: '';
        position: absolute;
        inset: 0;
        background: linear-gradient(135deg, var(--accent-dim) 0%, transparent 60%);
        opacity: 0;
        transition: opacity 0.2s;
        border-radius: inherit;
    }

    .topic-card:hover {
        border-color: var(--accent-border);
        transform: translateY(-3px);
        box-shadow: 0 8px 28px rgba(0,0,0,0.18);
    }

        .topic-card:hover::before {
            opacity: 1;
        }

        .topic-card:hover .tc-arrow {
            opacity: 1;
            transform: translateX(0);
        }

    .topic-card.coming-soon {
        opacity: 0.45;
        cursor: default;
        pointer-events: none;
    }

.tc-tag {
    font-family: 'Syne', sans-serif;
    font-size: 0.63rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--tag-text);
    margin-bottom: 0.9rem;
}

.tc-icon {
    font-family: 'STIX Two Text', 'Times New Roman', serif;
    font-size: 1.9rem;
    font-weight: 700;
    color: var(--accent);
    line-height: 1;
    margin-bottom: 0.75rem;
    opacity: 0.85;
}

.tc-title {
    font-family: 'Syne', sans-serif;
    font-size: 0.97rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 0.5rem;
    line-height: 1.3;
}

.tc-desc {
    font-size: 0.84rem;
    color: var(--text-secondary);
    line-height: 1.55;
    flex: 1;
    margin-bottom: 1rem;
}

.tc-features {
    display: flex;
    flex-wrap: wrap;
    gap: 0.35rem;
    margin-bottom: 0.25rem;
}

    .tc-features span {
        font-family: 'Syne', sans-serif;
        font-size: 0.63rem;
        font-weight: 600;
        letter-spacing: 0.05em;
        text-transform: uppercase;
        background: var(--surface2);
        border: 1px solid var(--border);
        border-radius: 999px;
        padding: 0.2rem 0.6rem;
        color: var(--text-muted);
    }

.tc-arrow {
    position: absolute;
    bottom: 1.2rem;
    right: 1.2rem;
    font-size: 1rem;
    color: var(--accent);
    opacity: 0;
    transform: translateX(-4px);
    transition: opacity 0.2s, transform 0.2s;
}

/* ── FOOTER ───────────────────────────────── */
.home-footer {
    text-align: center;
    padding: 1.5rem 1.5rem 3rem;
    font-family: 'Syne', sans-serif;
    font-size: 0.72rem;
    font-weight: 600;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--text-muted);
    border-top: 1px solid var(--border);
    margin: 0 2.5rem;
}