:root {
    --board: #1F2A24;
    --board-soft: #2A362F;
    --paper: #FBF8F0;
    --paper-line: #E4DFD0;
    --ink: #1F2A24;
    --ink-soft: #5B6B62;
    --chalk: #F4F1E8;
    --chalk-soft: #B8C2BA;
    --accent: #FF9F1C;
    --radius: 10px;
    --mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace;
    --display: 'Fraunces', Georgia, serif;
    --sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

* { box-sizing: border-box; }

body {
    font-family: var(--sans);
    line-height: 1.6;
    color: var(--ink);
    margin: 0;
    background: var(--paper);
}

.container { max-width: 1100px; margin: 0 auto; padding: 0 20px; }
.hidden { display: none; }

/* ---------- Board zone (header + hero) ---------- */
.board {
    background: linear-gradient(180deg, var(--board) 0%, var(--board) 70%, var(--board-soft) 100%);
}

header {
    position: sticky;
    top: 0;
    z-index: 10;
    background: rgba(31, 42, 36, 0.92);
    backdrop-filter: blur(6px);
    border-bottom: 1px solid rgba(244, 241, 232, 0.08);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 28px;
    padding: 14px 20px;
    flex-wrap: wrap;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    color: var(--chalk);
    flex-shrink: 0;
}

.logo-badge {
    width: 32px;
    height: 32px;
    border-radius: 8px;
    background: var(--accent);
    color: var(--board);
    font-family: var(--mono);
    font-weight: 700;
    font-size: 0.8rem;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.25s ease;
}

.logo-word {
    font-family: var(--mono);
    font-weight: 500;
    font-size: 0.95rem;
    letter-spacing: 0.02em;
}
.logo-word em { font-style: normal; color: var(--chalk-soft); }
/* Tabs styled like exam-code labels */
.tabs {
    display: flex;
    gap: 6px;
    overflow-x: auto;
    scrollbar-width: none;
}

.tabs::-webkit-scrollbar {
    display: none;
}

.tab {
    font-family: var(--mono);
    font-size: 0.8rem;
    font-weight: 700;
    letter-spacing: 0.03em;

    color: var(--chalk-soft);
    background: transparent;

    border: 1px solid transparent;
    border-radius: 6px;

    padding: 8px 14px;
    cursor: pointer;
    white-space: nowrap;

    transition:
        background-color .2s ease,
        color .2s ease,
        border-color .2s ease,
        transform .15s ease;
}

.tab:hover {
    color: var(--chalk);
    background: rgba(255,255,255,.05);
}

.tab.is-active {
    color: var(--board);
    background: var(--accent);
    border-color: transparent;
}

.tab:active {
    transform: translateY(1px);
}

.tab:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

/* Hero */
.hero {
    padding: 70px 0 90px;
    text-align: center;
}

h1 {
    font-family: var(--display);
    font-weight: 600;
    font-size: clamp(2.2rem, 5vw, 3.4rem);
    line-height: 1.12;
    color: var(--chalk);
    margin: 0 0 18px;
}

.course-name {
    color: var(--accent);
    font-style: italic;
    transition: color 0.25s ease;
}

.subtitle {
    font-size: 1.1rem;
    color: var(--chalk-soft);
    max-width: 640px;
    margin: 0 auto 44px;
}

/* Signup card — pinned index card */
.signup-card {
    background: var(--paper);
    padding: 34px 30px 26px;
    border-radius: 4px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.28);
    max-width: 380px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 10px;
    text-align: left;
    position: relative;
    transform: rotate(-1deg);
    transition: transform 0.3s ease;
}

.signup-card:hover,
.signup-card:focus-within {
    transform: rotate(0deg);
}

.signup-card::before {
    content: "";
    position: absolute;
    top: -7px;
    left: 50%;
    transform: translateX(-50%);
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--accent);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
    transition: background 0.25s ease;
}

.field-label {
    font-family: var(--mono);
    font-size: 0.7rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    color: var(--ink-soft);
    text-transform: uppercase;
    margin-bottom: -4px;
}

input, select {
    padding: 11px 12px;
    border: 1px solid var(--paper-line);
    border-radius: 6px;
    font-size: 0.95rem;
    font-family: var(--sans);
    background: #fff;
    color: var(--ink);
}

input:focus, select:focus {
    outline: 2px solid var(--accent);
    outline-offset: 1px;
}

button {
    margin-top: 8px;
    padding: 13px;
    background: var(--ink);
    color: var(--chalk);
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 600;
    font-size: 0.95rem;
    transition: background 0.2s ease, opacity 0.2s ease;
}
button:hover { background: var(--accent); color: var(--ink); }
button:disabled { background: var(--chalk-soft); color: var(--ink-soft); cursor: not-allowed; }

.course-alt-toggle {
    margin-top: -2px;
    padding: 4px;
    background: none;
    color: var(--ink-soft);
    font-size: 0.8rem;
    font-weight: 500;
    text-decoration: underline;
    text-underline-offset: 2px;
}
.course-alt-toggle:hover {
    background: none;
    color: var(--ink);
}

.form-footer {
    font-size: 0.78rem;
    color: var(--ink-soft);
    text-align: center;
    margin: 6px 0 0;
}

#message {
    font-size: 0.85rem;
    text-align: center;
    color: var(--ink-soft);
    min-height: 1.2em;
}

/* ---------- How it works ---------- */
.how-it-works {
    padding: 70px 0 10px;
}

.how-it-works h2 {
    font-family: var(--display);
    font-weight: 600;
    font-size: 1.7rem;
    margin: 0 0 36px;
}

.steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 40px;
}

.step-item { text-align: left; }

.step-item h3 {
    font-family: var(--display);
    font-weight: 600;
    font-size: 1.15rem;
    margin: 0 0 6px;
}

.step-item p {
    color: var(--ink-soft);
    margin: 0;
    font-size: 0.95rem;
}

/* ---------- FAQ ---------- */

.faq {
    max-width: 760px;
    padding: 40px 0 80px;
}

.faq h2 {
    margin-bottom: 28px;
}

.faq-item {
    border-top: 1px solid var(--paper-line);
}

.faq-item:last-child {
    border-bottom: 1px solid var(--paper-line);
}

.faq-item summary {
    list-style: none;
    cursor: pointer;

    display: flex;
    justify-content: space-between;
    align-items: center;

    padding: 20px 0;

    font-weight: 600;
    font-size: 1.05rem;
}

.faq-item summary::-webkit-details-marker {
    display: none;
}

.faq-item summary::after {
    content: "+";
    font-family: var(--mono);
    font-size: 1.2rem;
    color: var(--chalk-soft);
    transition: transform .2s ease;
}

.faq-item[open] summary::after {
    content: "−";
}

.faq-item p {
    margin: 0 0 20px;
    color: var(--board);
    line-height: 1.7;
    max-width: 80ch;
}

.faq-item summary:hover {
    color: var(--accent);
}

.faq-item summary:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 4px;
}

/* ---------- Section Divider ---------- */

.section-divider {
    height: 1px;
    background: var(--paper-line);
    max-width: 760px;
    margin: 24px auto 40px;
}

/* ---------- Features ---------- */
.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 40px;
    max-width: 640px;
    padding: 60px 0 60px;
}

.feature-item { text-align: left; }

.feature-mark {
    display: inline-block;
    font-family: var(--mono);
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--accent);
    border-bottom: 2px solid var(--accent);
    padding-bottom: 4px;
    margin-bottom: 14px;
}

.feature-item h3 {
    font-family: var(--display);
    font-weight: 600;
    font-size: 1.25rem;
    margin: 0 0 6px;
}

.feature-item p {
    color: var(--ink-soft);
    margin: 0;
    font-size: 0.95rem;
}

footer {
    text-align: center;
    padding: 30px 20px 50px;
    color: var(--ink-soft);
    font-size: 0.85rem;
}

/* ---------- Motion / accessibility ---------- */
@media (prefers-reduced-motion: reduce) {
    .signup-card, .tab, .course-name, .logo-badge, button {
        transition: none;
    }
}

@media (max-width: 640px) {
    .header-inner { justify-content: center; }
    .tabs { width: 100%; justify-content: flex-start; }
    .hero { padding: 50px 0 70px; }
}