/* ── tokens ─────────────────────────────────────────── */
:root {
  --ground: #F7F8FA;
  --surface: #FFFFFF;
  --sunk: #EEF0F4;
  --ink: #171A21;
  --muted: #5A6170;
  --line: #DCE0E8;
  --brand: #3B3FA8;
  --brand-soft: #E8E9F7;
  --amber: #9A6209;
  --amber-soft: #FBF1DC;
  --good: #1F6B45;
  --good-soft: #E2F0E8;
  --code-bg: #14161C;
  --code-ink: #E6E9EF;
  --on-brand: #FFFFFF;
  --shadow: 0 1px 2px rgba(23,26,33,.05), 0 4px 16px rgba(23,26,33,.05);
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --ground: #0E1014; --surface: #171A21; --sunk: #12151A; --ink: #E6E9EF;
    --muted: #98A0B0; --line: #2A2F3A; --brand: #9DA2F0; --brand-soft: #1E2140;
    --amber: #E0AE57; --amber-soft: #352B16; --good: #74C69A; --good-soft: #17301F;
    --code-bg: #08090C; --code-ink: #E6E9EF; --on-brand: #0E1014;
    --shadow: 0 1px 2px rgba(0,0,0,.35), 0 4px 16px rgba(0,0,0,.3);
  }
}
:root[data-theme="dark"] {
  --ground: #0E1014; --surface: #171A21; --sunk: #12151A; --ink: #E6E9EF;
  --muted: #98A0B0; --line: #2A2F3A; --brand: #9DA2F0; --brand-soft: #1E2140;
  --amber: #E0AE57; --amber-soft: #352B16; --good: #74C69A; --good-soft: #17301F;
  --code-bg: #08090C; --code-ink: #E6E9EF; --on-brand: #0E1014;
  --shadow: 0 1px 2px rgba(0,0,0,.35), 0 4px 16px rgba(0,0,0,.3);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } * { transition: none !important; } }

body {
  margin: 0; background: var(--ground); color: var(--ink);
  font-family: "Public Sans", ui-sans-serif, system-ui, sans-serif;
  font-size: 17px; line-height: 1.6; -webkit-text-size-adjust: 100%;
}
.wrap { max-width: 1000px; margin-inline: auto; padding-inline: 20px; }

h1, h2, h3, h4 {
  font-family: "Archivo", "Public Sans", system-ui, sans-serif;
  font-weight: 700; line-height: 1.12; margin: 0; text-wrap: balance; letter-spacing: -0.02em;
}
h1 { font-size: clamp(2.1rem, 6vw, 3.2rem); }
h2 { font-size: clamp(1.5rem, 4vw, 2rem); }
h3 { font-size: 1.12rem; }
h4 { font-size: 1.02rem; }
p { margin: 0; max-width: 72ch; }
a { color: var(--brand); text-underline-offset: 2px; }
:focus-visible { outline: 2.5px solid var(--amber); outline-offset: 2px; border-radius: 4px; }

code {
  font-family: "JetBrains Mono", ui-monospace, Menlo, monospace; font-size: .86em;
  background: var(--brand-soft); color: var(--ink); padding: 1px 6px; border-radius: 5px;
}
pre {
  margin: 0; background: var(--code-bg); color: var(--code-ink); border-radius: 10px;
  padding: 16px 18px; overflow-x: auto; position: relative;
}
pre code { font-size: .84rem; line-height: 1.7; background: none; color: inherit; padding: 0; white-space: pre; }
.copy {
  position: absolute; top: 8px; right: 8px; opacity: 0; cursor: pointer;
  font: 600 .72rem/1 "Public Sans", sans-serif; padding: 6px 10px; border-radius: 6px;
  border: 1px solid rgba(255,255,255,.22); background: rgba(255,255,255,.1); color: #E6E9EF;
  transition: opacity .15s;
}
pre:hover .copy, .copy:focus-visible { opacity: 1; }
@media (hover: none) { .copy { opacity: 1; } }
.copy.done { background: var(--brand); border-color: var(--brand); color: var(--on-brand); }

/* ── hero ───────────────────────────────────────────── */
.hero { background: linear-gradient(180deg, var(--brand-soft), var(--ground)); border-bottom: 1px solid var(--line); padding-block: 18px 52px; }
.topbar { display: flex; justify-content: space-between; align-items: center; margin-bottom: 28px; gap: 12px; }
.eyebrow {
  font-family: "JetBrains Mono", monospace; font-size: .72rem; font-weight: 600;
  letter-spacing: .04em; text-transform: uppercase; color: var(--brand);
  background: var(--surface); border: 1px solid var(--line); padding: 5px 11px; border-radius: 999px;
}
.theme { font-size: 1rem; line-height: 1; width: 36px; height: 36px; cursor: pointer; border-radius: 50%; border: 1px solid var(--line); background: var(--surface); color: var(--ink); flex: none; }
.hero .lead { margin-top: 16px; font-size: 1.14rem; max-width: 62ch; }
.hero .sub { margin-top: 14px; color: var(--muted); font-size: .98rem; max-width: 62ch; }
.herolinks { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 28px; }
.btn {
  display: inline-block; padding: 9px 18px; border-radius: 8px; font-weight: 700; font-size: .94rem;
  text-decoration: none; border: 1.5px solid var(--brand); color: var(--brand); background: var(--surface);
}
.btn:hover { background: var(--brand-soft); }
.btn.primary { background: var(--brand); color: var(--on-brand); }

/* ── sections ───────────────────────────────────────── */
main { padding-block: 8px 40px; }
section { padding-block: 46px; border-bottom: 1px solid var(--line); scroll-margin-top: 12px; }
section > h2 { margin-bottom: 14px; }
section > p { margin-bottom: 20px; }
h3.sub { margin-top: 36px; margin-bottom: 14px; }
.after { margin-top: 22px; color: var(--muted); font-size: .97rem; }
.after em { color: var(--ink); font-style: italic; }

/* ── families ───────────────────────────────────────── */
ol.families {
  list-style: none; margin: 26px 0 0; padding: 0;
  display: grid; grid-template-columns: repeat(auto-fit, minmax(290px, 1fr)); gap: 2px;
  background: var(--line); border: 1px solid var(--line); border-radius: 12px; overflow: hidden;
}
/* Ten items into three columns leaves one alone, so the last one spans the row. */
ol.families > li:last-child { grid-column: 1 / -1; }
ol.families > li { display: grid; grid-template-columns: 42px 1fr; gap: 14px; align-items: start; padding: 16px 18px; background: var(--surface); }
.n {
  font-family: "JetBrains Mono", monospace; font-size: .8rem; font-weight: 600;
  display: grid; place-items: center; width: 30px; height: 30px; border-radius: 7px;
  background: var(--brand-soft); color: var(--brand);
}
ol.families h3 { font-size: 1rem; margin-bottom: 4px; }
ol.families p { font-size: .93rem; color: var(--muted); }

/* ── tables ─────────────────────────────────────────── */
.tablewrap { overflow-x: auto; border: 1px solid var(--line); border-radius: 12px; background: var(--surface); }
table { border-collapse: collapse; width: 100%; font-size: .93rem; }
th, td { text-align: left; padding: 11px 14px; border-bottom: 1px solid var(--line); vertical-align: top; }
thead th { font-size: .72rem; letter-spacing: .06em; text-transform: uppercase; color: var(--muted); font-weight: 700; white-space: nowrap; }
tbody th { font-weight: 700; white-space: nowrap; }
tr:last-child td, tr:last-child th { border-bottom: 0; }
table.matrix td { min-width: 165px; }
td.lead-cell { background: var(--good-soft); color: var(--ink); font-weight: 600; }
td.gap { background: var(--amber-soft); color: var(--ink); font-weight: 600; }
.legend { margin-top: 12px; font-size: .88rem; color: var(--muted); display: flex; flex-wrap: wrap; align-items: center; gap: 6px; }
.key { display: inline-block; width: 14px; height: 14px; border-radius: 4px; border: 1px solid var(--line); vertical-align: -2px; }
.lead-key { background: var(--good-soft); }
.gap-key { background: var(--amber-soft); }

/* ── callout ────────────────────────────────────────── */
.callout { margin-top: 30px; padding: 20px 22px; background: var(--amber-soft); border-radius: 12px; border-left: 4px solid var(--amber); }
.callout h3 { margin-bottom: 10px; }
.callout ul { margin: 12px 0 0; padding-left: 20px; display: grid; gap: 8px; }
.callout p, .callout li { font-size: .97rem; }

/* ── cards ──────────────────────────────────────────── */
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 12px; }
.card {
  display: block; padding: 17px 19px; background: var(--surface); border: 1px solid var(--line);
  border-radius: 12px; text-decoration: none; color: inherit; box-shadow: var(--shadow);
}
.card:hover { border-color: var(--brand); }
.card h4 { margin-bottom: 7px; color: var(--brand); }
.card p { font-size: .93rem; color: var(--muted); }
.card.wide { grid-column: 1 / -1; }

/* ── exercise list ──────────────────────────────────── */
ol.exlist { list-style: none; margin: 24px 0 0; padding: 0; counter-reset: ex; display: grid; gap: 2px; background: var(--line); border: 1px solid var(--line); border-radius: 12px; overflow: hidden; }
ol.exlist > li { counter-increment: ex; background: var(--surface); }
ol.exlist a { display: grid; grid-template-columns: 46px 1fr; gap: 14px; padding: 15px 18px; text-decoration: none; color: inherit; }
ol.exlist a:hover { background: var(--sunk); }
/* The number sits in column one; everything else stacks in column two.
   Without this the paragraph lands in the 46px column and wraps one word per line. */
ol.exlist a::before {
  content: counter(ex, decimal-leading-zero);
  grid-column: 1; grid-row: 1;
  font-family: "JetBrains Mono", monospace; font-size: .8rem; font-weight: 600; color: var(--muted); padding-top: 3px;
}
ol.exlist a > * { grid-column: 2; min-width: 0; }
ol.exlist a > h4 { grid-row: 1; }
ol.exlist h4 { margin-bottom: 4px; display: flex; align-items: center; gap: 9px; flex-wrap: wrap; }
ol.exlist p { font-size: .93rem; color: var(--muted); }
.tag { font-family: "JetBrains Mono", monospace; font-size: .68rem; font-weight: 600; text-transform: uppercase; letter-spacing: .04em; color: var(--amber); background: var(--amber-soft); padding: 3px 8px; border-radius: 999px; }

/* ── faq ────────────────────────────────────────────── */
dl.faq { margin: 22px 0 0; display: grid; gap: 2px; }
dl.faq dt { font-weight: 700; font-family: "Archivo", sans-serif; padding: 16px 0 5px; border-top: 1px solid var(--line); }
dl.faq dd { margin: 0 0 14px; font-size: .96rem; color: var(--muted); max-width: 72ch; }
dl.faq dd code { color: var(--ink); }

footer { padding-block: 32px 48px; }
.fine { color: var(--muted); font-size: .88rem; }

@media (max-width: 560px) {
  body { font-size: 16px; }
  section { padding-block: 34px; }
  ol.families > li { grid-template-columns: 34px 1fr; gap: 11px; }
  ol.exlist a { grid-template-columns: 34px 1fr; gap: 10px; }
}

/* ── study plan ─────────────────────────────────────── */
.card.static { cursor: default; box-shadow: none; }
.card.static:hover { border-color: var(--line); }
.card.static h4 { color: var(--ink); }
.weeks { display: grid; gap: 14px; }
.week { padding: 20px 22px; background: var(--surface); border: 1px solid var(--line); border-radius: 12px; box-shadow: var(--shadow); }
.week.build { background: var(--brand-soft); border-color: var(--brand); }
.week header { display: flex; align-items: baseline; gap: 12px; flex-wrap: wrap; margin-bottom: 10px; }
.wk {
  font-family: "JetBrains Mono", monospace; font-size: .68rem; font-weight: 600;
  letter-spacing: .06em; text-transform: uppercase; color: var(--on-brand);
  background: var(--brand); padding: 4px 10px; border-radius: 999px; flex: none;
}
.week .goal { color: var(--muted); font-size: .95rem; }
.week ol { margin: 14px 0 0; padding-left: 22px; display: grid; gap: 7px; font-size: .95rem; }
.week ol li::marker { color: var(--muted); font-weight: 700; }
.week .check { margin-top: 16px; padding: 12px 15px; font-size: .93rem; background: var(--sunk); border-radius: 9px; border-left: 3px solid var(--amber); }
.week.build .check { background: var(--surface); }

/* ── self test ──────────────────────────────────────── */
ol.selftest { margin: 18px 0 0; padding: 0; list-style: none; counter-reset: q; display: grid; gap: 2px; background: var(--line); border: 1px solid var(--line); border-radius: 12px; overflow: hidden; }
ol.selftest li {
  counter-increment: q; background: var(--surface); padding: 13px 18px 13px 52px; position: relative; font-size: .96rem;
}
ol.selftest li::before {
  content: counter(q); position: absolute; left: 18px; top: 13px;
  font-family: "JetBrains Mono", monospace; font-size: .78rem; font-weight: 600; color: var(--brand);
}