/* ============================================
   Statistics and Data Science II - course page
   Palette and type follow the 2026 slide theme,
   so the page and the slides feel like one thing.
   ============================================ */

*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

:root {
    --sans: "Source Sans 3", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    --serif: "Source Serif 4", Georgia, "Times New Roman", serif;

    --argument: #9a5b3d;
    --technique: #2c5f7c;
    --craft: #4a6f4e;

    --ink: #17181a;
    --body: #33383d;
    --muted: #858b91;
    --rule: #c9ccd0;
    --hair: #e7e9eb;
    --bg: #ffffff;
    --tint: #fbfafa;

    --wrap: 820px;
}

html { font-size: 16px; -webkit-text-size-adjust: 100%; }

body {
    font-family: var(--sans);
    font-size: 1.0625rem;
    line-height: 1.6;
    color: var(--body);
    background: var(--bg);
    -webkit-font-smoothing: antialiased;
}

body.menu-open { overflow: hidden; }

h1, h2, h3 { font-family: var(--serif); color: var(--ink); font-weight: 600; line-height: 1.2; }

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

b { font-weight: 600; color: var(--ink); }

.sr {
    position: absolute;
    width: 1px; height: 1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
    white-space: nowrap;
}

.skip {
    position: absolute;
    top: -100px;
    left: 0;
    z-index: 50;
    background: var(--argument);
    color: #fff;
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
    text-decoration: none;
}
.skip:focus { top: 0; }

/* --- top bar: deliberately almost empty --- */

.bar {
    position: sticky;
    top: 0;
    z-index: 40;
    background: rgba(255, 255, 255, 0.94);
    backdrop-filter: saturate(160%) blur(8px);
    border-bottom: 1px solid var(--hair);
}

.bar-inner {
    max-width: var(--wrap);
    margin: 0 auto;
    padding: 0.7rem 1.25rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.bar-code {
    font-size: 0.72rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--muted);
}

.menu-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 34px;
    height: 34px;
    margin-right: -6px;
    background: none;
    border: 0;
    border-radius: 4px;
    cursor: pointer;
    color: var(--body);
}
.menu-btn:hover { color: var(--argument); }
.menu-btn:focus-visible { outline: 2px solid var(--argument); outline-offset: 1px; }

.menu-bars { display: block; width: 18px; }
.menu-bars i {
    display: block;
    height: 1.5px;
    background: currentColor;
    border-radius: 1px;
}
.menu-bars i + i { margin-top: 4px; }

.menu {
    max-width: var(--wrap);
    margin: 0 auto;
    padding: 0 1.25rem 0.9rem;
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 0.45rem;
}
.menu[hidden] { display: none; }

.menu a {
    font-size: 0.92rem;
    color: var(--body);
    text-decoration: none;
    border-bottom: 1px solid transparent;
}
.menu a:hover { color: var(--argument); border-bottom-color: var(--argument); }

.menu-away {
    margin-top: 0.3rem;
    padding-top: 0.55rem;
    border-top: 1px solid var(--hair) !important;
    width: 100%;
    text-align: right;
    font-size: 0.82rem !important;
    color: var(--muted) !important;
}
.menu-away:hover { color: var(--argument) !important; }

/* --- page furniture --- */

main { max-width: var(--wrap); margin: 0 auto; padding: 0 1.25rem; }

.hero { padding: 4rem 0 2.75rem; }

.eyebrow {
    font-size: 0.72rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--argument);
    margin-bottom: 0.9rem;
}

.hero h1 {
    font-size: clamp(2rem, 6vw, 2.9rem);
    letter-spacing: -0.015em;
    margin-bottom: 0.9rem;
}

.lede {
    font-size: 1.1rem;
    color: var(--body);
    max-width: 38em;
}

.block { padding: 2.5rem 0; border-top: 1px solid var(--hair); }

.block h2 {
    font-size: 1.45rem;
    margin-bottom: 0.3rem;
}

.block-note {
    color: var(--muted);
    font-size: 0.95rem;
    margin-bottom: 1.6rem;
}

/* a block that drops its note still needs air under the heading */
.block h2 + .tool,
.block h2 + .weeks,
.block h2 + .archive-line { margin-top: 1.6rem; }

/* --- weeks --- */

.weeks { list-style: none; }

.week {
    display: flex;
    align-items: baseline;
    gap: 0.9rem;
    padding: 0.7rem 0;
    border-bottom: 1px solid var(--hair);
}
.week:first-child { border-top: 1px solid var(--hair); }

.week-no {
    flex: 0 0 4.6rem;
    font-size: 0.72rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--muted);
}

.week-title { flex: 1 1 auto; color: var(--muted); }

.is-live .week-no { color: var(--argument); }
.is-live .week-title { color: var(--ink); font-weight: 600; }

.week-state {
    flex: 0 0 auto;
    font-size: 0.82rem;
    color: var(--rule);
}

.week-link {
    flex: 0 0 auto;
    font-size: 0.9rem;
    font-weight: 600;
    text-decoration: none;
    color: var(--technique);
    border-bottom: 1px solid currentColor;
}
.week-link:hover { color: var(--argument); }

/* --- tools --- */

.tool { margin-bottom: 3rem; }
.tool:last-child { margin-bottom: 0; }

.tool h3 {
    font-size: 1.15rem;
    margin-bottom: 0.5rem;
}

.tool p {
    max-width: 38em;
    margin-bottom: 0.8rem;
}

.knobs {
    margin-top: 1.4rem;
    padding: 1.1rem 1.2rem 1.2rem;
    background: var(--tint);
    border: 1px solid var(--hair);
    border-radius: 8px;
}

.canvas-wrap { width: 100%; }
.canvas-wrap canvas { display: block; touch-action: pan-y; }

.eq {
    font-family: var(--serif);
    font-size: 1.1rem;
    color: var(--ink);
    text-align: center;
    margin: 0.5rem 0 0.9rem;
}

.knob-row {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.5rem 0.9rem;
}
.knob-row + .knob-row {
    margin-top: 0.75rem;
    padding-top: 0.75rem;
    border-top: 1px solid var(--hair);
}

.knob-row label {
    font-size: 0.85rem;
    color: var(--body);
    white-space: nowrap;
}

.knob {
    display: flex;
    align-items: center;
    gap: 0.55rem;
    flex: 1 1 240px;
}

.knob-row input[type="range"] {
    flex: 1 1 auto;
    min-width: 90px;
    accent-color: var(--argument);
    cursor: pointer;
}

.knob-checks label {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    cursor: pointer;
}
.knob-checks input[type="checkbox"] { accent-color: var(--argument); cursor: pointer; }

.reset {
    font-family: var(--sans);
    font-size: 0.78rem;
    color: var(--muted);
    background: none;
    border: 1px solid var(--rule);
    border-radius: 4px;
    padding: 0.2rem 0.6rem;
    cursor: pointer;
}
.reset:hover { color: var(--argument); border-color: var(--argument); }

.stat {
    font-size: 0.85rem;
    color: var(--body);
    margin-left: auto;
}
.stat .sep { color: var(--rule); margin: 0 0.5rem; }

/* --- archive --- */

.archive-line {
    display: flex;
    gap: 0.9rem;
    align-items: baseline;
    color: var(--muted);
    font-size: 0.95rem;
}
.archive-line span {
    flex: 0 0 4.6rem;
    font-size: 0.72rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

/* --- foot --- */

.foot {
    max-width: var(--wrap);
    margin: 0 auto;
    padding: 2.5rem 1.25rem 3.5rem;
    border-top: 1px solid var(--hair);
    font-size: 0.85rem;
    color: var(--muted);
}
.foot a { color: var(--muted); }
.foot a:hover { color: var(--argument); }

@media (max-width: 560px) {
    .hero { padding: 2.75rem 0 2rem; }
    .week { flex-wrap: wrap; gap: 0.3rem 0.8rem; }
    .week-no { flex-basis: 100%; }
    .week-title { flex: 1 1 auto; }
    .stat { margin-left: 0; flex-basis: 100%; }
}