/* ---------- subject colours: every subject picks one from this palette ---------- */
[data-color="green"]  { --sub: #1E9E7A; --sub-d: #0E6B52; }
[data-color="blue"]   { --sub: #3A86C8; --sub-d: #235F96; }
[data-color="violet"] { --sub: #7B5CC4; --sub-d: #573D9A; }
[data-color="orange"] { --sub: #E0852B; --sub-d: #A85F14; }
[data-color="rose"]   { --sub: #D4537E; --sub-d: #9C3558; }
[data-color="teal"]   { --sub: #13A0A8; --sub-d: #0B6F76; }
[data-color] { --sub-t: color-mix(in srgb, var(--sub) 14%, var(--surface)); }

/* ---------- subject hub on the home screen ---------- */
.sec-row { display: flex; align-items: center; justify-content: space-between; margin: 26px 18px 10px; }
.sec-row h2 { font-size: 18px; font-weight: 600; }
.subjects { display: grid; gap: 12px; padding: 0 18px; }
.subject {
  display: flex; align-items: center; gap: 14px; background: var(--surface); color: inherit; text-decoration: none;
  border: 2px solid var(--line); border-bottom-width: 5px; border-radius: 20px; padding: 14px 16px; min-height: 84px;
  transition: transform .08s;
}
.subject:active { transform: translateY(2px); }
.subject .ic-tile { width: 56px; height: 56px; flex: none; border-radius: 18px; background: var(--sub); color: #fff; display: grid; place-items: center; box-shadow: 0 4px 0 var(--sub-d); }
.subject .ic-tile .ic { width: 28px; height: 28px; }
.subject .info { flex: 1; min-width: 0; }
.subject h3 { font-size: 16px; font-weight: 600; line-height: 1.4; margin: 0; overflow-wrap: anywhere; }
.subject .meta { font-size: 13px; color: var(--ink-2); margin-top: 2px; }
.subject .bar { height: 10px; margin-top: 8px; }
.subject .bar > i { background: var(--sub); }
.subject.done { border-color: var(--sub); background: var(--sub-t); }

.sub-top { background: var(--sub); color: #fff; padding: 12px 18px 64px; border-radius: 0 0 var(--r-l) var(--r-l); }
.sub-top h1 { font-size: 24px; font-weight: 600; line-height: 1.4; margin-top: 12px; }
.sub-top .sub { color: rgba(255, 255, 255, .85); font-size: 14px; }
.sub-top .bar { background: rgba(0, 0, 0, .2); height: 10px; margin-top: 14px; }
.sub-top .bar > i { background: #fff; }
.sub-top .back { color: #fff; text-decoration: none; display: inline-flex; align-items: center; gap: 4px; min-height: 44px; font-size: 14px; }
.sub-tools { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; margin: -40px 18px 0; position: relative; }
.sub-tools a { background: var(--surface); border: 2px solid var(--line); border-radius: 16px; padding: 12px 6px; text-align: center; text-decoration: none; color: var(--ink); font-size: 13px; font-weight: 500; display: grid; gap: 4px; justify-items: center; min-height: 72px; }
.sub-tools a .ic { color: var(--sub); }
.sub-tools a b { color: var(--sub-d); font-size: 15px; }
.path .node:not(.locked):not(.done):not(.boss) .tile { background: var(--gold); }
.node.done .tile { background: var(--sub, var(--go)); box-shadow: 0 7px 0 var(--sub-d, var(--go-d)); }

/* ---------- top icon buttons (search, saved) ---------- */
.top-icons { display: flex; }
.top-icons .icon-btn { color: #fff; }

/* ---------- search and saved ---------- */
.searchbox { position: sticky; top: 0; background: var(--bg); padding: 12px 18px; z-index: 3; }
.searchbox .input { min-height: 52px; font-size: 17px; }
.result-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 10px; }
.result-list a, .result-list .row-card { display: block; background: var(--surface); border: 2px solid var(--line); border-radius: 16px; padding: 12px 14px; color: inherit; text-decoration: none; }
.result-list a:hover { border-color: var(--go); }
.result-list b { font-weight: 500; }
.result-list small { display: block; color: var(--ink-2); font-size: 13px; margin-top: 2px; overflow-wrap: anywhere; }
.row-card { display: flex; align-items: center; gap: 12px; }
.row-card .grow { flex: 1; min-width: 0; overflow-wrap: anywhere; }
.practice-box { background: var(--surface); border: 2px solid var(--line); border-radius: 20px; padding: 16px; }
.star-btn { color: var(--ink-3); }
.star-btn[aria-pressed="true"] { color: var(--gold-d); }
.star-btn[aria-pressed="true"] .ic { fill: var(--gold); }
/* written exercises and "my corrections" */
textarea.code.is-sent { opacity: .75; }
.sub-card { display: grid; gap: 8px; }
.sub-card .prompt-line { font-weight: 500; overflow-wrap: anywhere; }
.code-view { background: var(--surface-2, var(--surface)); border: 2px solid var(--line); border-radius: 12px; padding: 12px; overflow-x: auto; text-align: left; font-family: ui-monospace, Consolas, monospace; font-size: 14px; white-space: pre; }
/* confidence picker (before checking) and "why did I miss it" picker (after a wrong answer) */
.conf { display: grid; gap: 6px; }
.conf > span { font-size: 13px; color: var(--ink-2); }
.conf-row { display: flex; gap: 8px; }
.conf-row button, .why-row button { min-height: 44px; flex: 1; border: 2px solid var(--line); border-radius: 14px; background: var(--surface); color: var(--ink); font: inherit; font-size: 14px; cursor: pointer; }
.conf-row button[aria-pressed="true"], .why-row button[aria-pressed="true"] { border-color: var(--go); background: var(--go-soft, var(--surface)); font-weight: 600; }
.why { display: grid; gap: 6px; margin-bottom: 10px; }
.why > span { font-size: 13px; color: var(--ink-2); }
.why-row { display: flex; gap: 6px; flex-wrap: wrap; }
.why-row button { flex: 1 1 40%; padding: 6px 10px; }
.research-note { color: var(--ink-2); font-size: 13px; line-height: 1.6; }
.fb-tools { display: flex; gap: 8px; flex-wrap: wrap; }
.fb-tools .btn { flex: 1; min-width: 120px; }

/* ---------- review hub ---------- */
.hub-card { background: var(--surface); border: 2px solid var(--line); border-radius: 20px; padding: 16px; display: grid; gap: 12px; }
.hub-card h2 { font-size: 17px; font-weight: 600; display: flex; align-items: center; gap: 10px; }
.hub-card h2 .ic { color: var(--go); }
.hub-row { display: flex; align-items: center; gap: 12px; padding-top: 10px; border-top: 1px solid var(--line); }
.hub-row:first-of-type { border-top: 0; padding-top: 0; }
.hub-row .grow { flex: 1; min-width: 0; }
.hub-row .grow b { font-weight: 500; display: block; overflow-wrap: anywhere; }
.hub-row .grow small { color: var(--ink-2); font-size: 13px; }
.dot-sub { width: 14px; height: 14px; border-radius: 50%; background: var(--sub); flex: none; }
.mini-stats { display: flex; gap: 6px; flex-wrap: wrap; font-size: 12px; margin-top: 4px; }
.mini-stats span { background: var(--line); border-radius: 99px; padding: 2px 10px; color: var(--ink-2); }
.mini-stats span.hot { background: var(--bad-t); color: var(--bad-ink); font-weight: 600; }

/* ---------- flashcard session ---------- */
.deck-card { min-height: 260px; font-size: 22px; padding: 24px; }
.deck-box { text-align: center; font-size: 13px; color: var(--ink-2); margin-bottom: 10px; }
.rate-row { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-top: 16px; }

/* ---------- exam ---------- */
.exam-top { position: sticky; top: 0; background: var(--bg); z-index: 3; padding: 10px 14px 6px; display: flex; align-items: center; gap: 10px; }
.timer { margin-inline-start: auto; font: 600 18px var(--mono); direction: ltr; background: var(--surface); border: 2px solid var(--line); border-radius: 12px; padding: 4px 12px; }
.timer.low { color: var(--bad); border-color: var(--bad); }
.qnav { display: flex; flex-wrap: wrap; gap: 6px; padding: 0 18px 8px; }
.qnav button { width: 36px; height: 36px; border-radius: 10px; border: 2px solid var(--line); background: var(--surface); font: 500 13px var(--font); cursor: pointer; }
.qnav button.answered { background: var(--go-t); border-color: var(--go); color: var(--go-ink); }
.qnav button[aria-current="true"] { outline: 3px solid var(--p2); outline-offset: 1px; }
.exam-nav { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.exam-score { font-size: 44px; font-weight: 700; }
.review-item { background: var(--surface); border: 2px solid var(--line); border-radius: 16px; padding: 12px 14px; }
.review-item.ok { border-color: var(--go); }
.review-item.no { border-color: var(--bad); }
.review-item p { margin: 0 0 6px; overflow-wrap: anywhere; }
.review-item pre { margin: 4px 0 6px; white-space: pre-wrap; font: 500 13px/1.6 var(--mono); direction: ltr; text-align: left; background: var(--line); border-radius: 8px; padding: 6px 10px; }

/* ---------- statistics ---------- */
.cal { display: grid; grid-template-columns: repeat(7, 1fr); gap: 6px; }
.cal i { aspect-ratio: 1; border-radius: 8px; background: var(--line); display: block; }
.cal i.lv1 { background: color-mix(in srgb, var(--go) 30%, var(--line)); }
.cal i.lv2 { background: color-mix(in srgb, var(--go) 55%, var(--line)); }
.cal i.lv3 { background: color-mix(in srgb, var(--go) 80%, var(--line)); }
.cal i.lv4 { background: var(--go); }
.cal i.today { outline: 2px solid var(--ink); outline-offset: 1px; }
.legend { display: flex; align-items: center; gap: 6px; font-size: 12px; color: var(--ink-2); margin-top: 8px; }
.legend i { width: 14px; height: 14px; border-radius: 4px; display: inline-block; background: var(--line); }
.weeks { display: flex; align-items: flex-end; gap: 8px; height: 140px; direction: ltr; }
.weeks div { flex: 1; display: flex; flex-direction: column; justify-content: flex-end; align-items: center; height: 100%; font-size: 11px; color: var(--ink-2); gap: 4px; }
.weeks i { width: 100%; background: var(--gold); border-radius: 8px 8px 2px 2px; min-height: 3px; display: block; }
.mastery-row { display: grid; gap: 4px; margin-bottom: 12px; }
.mastery-row .top { display: flex; justify-content: space-between; gap: 8px; font-size: 14px; }
.mastery-row .bar { height: 12px; }
.mastery-row .bar > i { background: var(--sub, var(--go)); }
.big-stats { display: grid; grid-template-columns: repeat(2, 1fr); gap: 10px; }

/* ---------- code playground ---------- */
.pg-hints { list-style: none; margin: 0 0 14px; padding: 0; display: grid; gap: 6px; font-size: 14.5px; }
.pg-hints li { display: flex; gap: 8px; align-items: flex-start; padding: 8px 12px; border: 2px solid var(--line); border-radius: 12px; background: var(--surface); }
.pg-hints li::before { content: ""; width: 16px; height: 16px; margin-top: 3px; border-radius: 50%; border: 2px solid var(--ink-3); flex: none; }
.pg-hints li.is-right { border-color: var(--go); background: var(--go-t); color: var(--go-ink); }
.pg-hints li.is-right::before { background: var(--go); border-color: var(--go); }
.pg-hints li.is-wrong { border-color: var(--bad); background: var(--bad-t); color: var(--bad-ink); }
.pg-hints li.is-wrong::before { background: var(--bad); border-color: var(--bad); }
.pg-bar { display: flex; gap: 8px; align-items: center; margin: 8px 0; }
.pg-bar .grow { flex: 1; }
.pg-frame { display: block; width: 100%; height: 240px; border: 2px solid var(--line); border-radius: 14px; background: #fff; }
.pg-label { font-size: 13px; color: var(--ink-2); margin: 10px 0 4px; }