:root {
    --bg: #f8fafc;
    --card: #fff;
    --text: #0f172a;
    --muted: #475569;
    --border: #e2e8f0;
    --orange: #f38020;
    --blue: #2563eb;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #0f172a;
        --card: #1e293b;
        --text: #f8fafc;
        --muted: #cbd5e1;
        --border: #334155;
    }
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    font: 16px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
}

.wrap {
    max-width: 1040px;
    margin: auto;
    padding: 0 20px;
}

nav {
    display: flex;
    justify-content: space-between;
    gap: 16px;
    align-items: center;
    padding: 20px 0;
    border-bottom: 1px solid var(--border);
}

nav div {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
}

a {
    color: var(--orange);
}

nav a {
    font-weight: 650;
    text-decoration: none;
    color: var(--muted);
}

nav .brand {
    font-size: 1.2rem;
    color: var(--text);
    font-weight: 800;
}

.hero {
    padding: 64px 0 38px;
    max-width: 780px;
}

.hero.compact {
    padding: 40px 0 18px;
}

.eyebrow {
    font-size: 0.8rem;
    letter-spacing: 0.08em;
    color: var(--orange);
    font-weight: 800;
}

h1 {
    font-size: clamp(2rem, 5vw, 3.2rem);
    line-height: 1.16;
    letter-spacing: -0.04em;
    margin: 12px 0;
}

h2 {
    font-size: 1.5rem;
}

h3 {
    margin-top: 0;
}

p {
    margin-top: 8px;
}

.hero p, .muted {
    color: var(--muted);
}

section {
    margin: 26px 0 40px;
}

.cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(235px, 1fr));
    gap: 18px;
}

.card, .panel {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 23px;
}

.card {
    display: block;
    color: var(--text);
    text-decoration: none;
    transition: transform 0.15s, border-color 0.15s;
}

.card:hover, .card:focus {
    border-color: var(--orange);
    transform: translateY(-2px);
}

.card.selected {
    outline: 3px solid var(--orange);
}

.card p {
    color: var(--muted);
}

.card strong {
    color: var(--orange);
}

.pill {
    display: inline-block;
    border-radius: 20px;
    padding: 3px 10px;
    font-size: 0.78rem;
    font-weight: 750;
    background: rgba(243, 128, 32, 0.13);
    color: var(--orange);
}

.section-head {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
}

.two-col {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 18px;
}

.evidence-item {
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 12px;
    margin: 10px 0;
}

.evidence-item pre {
    white-space: pre-wrap;
    overflow-wrap: anywhere;
    font: inherit;
    margin: 4px 0;
}

.evidence-item strong {
    display: block;
}

.check {
    display: flex;
    gap: 9px;
    align-items: center;
    margin-top: 20px;
}

.choice {
    display: block;
    margin: 10px 0;
    padding: 12px;
    border: 1px solid var(--border);
    border-radius: 8px;
    cursor: pointer;
}

.choice input {
    margin-right: 8px;
}

button, .button {
    display: inline-block;
    background: var(--orange);
    color: #111827;
    border: 0;
    border-radius: 8px;
    padding: 12px 18px;
    font-weight: 800;
    cursor: pointer;
    text-decoration: none;
    font-size: 1rem;
    margin-top: 12px;
}

button:disabled {
    opacity: 0.45;
    cursor: not-allowed;
}

.secondary {
    background: transparent;
    border: 1px solid var(--border);
    color: var(--text);
    margin-left: 8px;
}

.results {
    margin-top: 18px;
}

select {
    display: block;
    max-width: 100%;
    padding: 10px;
    margin: 8px 0;
    border: 1px solid var(--border);
    border-radius: 6px;
    background: var(--card);
    color: var(--text);
}

.output {
    margin-top: 18px;
    border: 1px dashed var(--border);
    border-radius: 8px;
    padding: 18px;
    white-space: pre-wrap;
    overflow-wrap: anywhere;
}

.feedback {
    font-weight: 700;
}

.lesson {
    margin-top: 18px;
    border-left: 5px solid var(--orange);
}

.small {
    font-size: 0.85rem;
}

footer {
    border-top: 1px solid var(--border);
    padding: 25px 0;
    margin-top: 55px;
    color: var(--muted);
}

@media (max-width: 680px) {
    .two-col {
        grid-template-columns: 1fr;
    }
    nav {
        align-items: flex-start;
        flex-direction: column;
    }
    .hero {
        padding-top: 36px;
    }
    .secondary {
        margin-left: 0;
    }
}

@media (prefers-reduced-motion: reduce) {
    * {
        transition: none !important;
    }
}