/* T.10 exercise bank — shared lab-notebook look. */
:root, [data-theme="dark"] {
    --bg: #0b0d0c; --surface: #131716; --surface2: #191f1d;
    --line: #26302b; --line-soft: #1c2320;
    --ink: #e9eee6; --muted: #a9b4a9; --faint: #6e7a71;
    --lime: #c8f04b; --lime-ink: #1a2005; --amber: #ffa14a;
    --serif: "Newsreader", Georgia, serif;
    --mono: "JetBrains Mono", ui-monospace, Menlo, Consolas, monospace;
    --sans: system-ui, -apple-system, "Segoe UI", Arial, sans-serif;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: var(--sans); background: var(--bg); color: var(--ink); line-height: 1.6; font-size: 16px; -webkit-font-smoothing: antialiased; }
.wrap { max-width: 960px; margin: auto; padding: 0 28px; }
.skip-link { position: absolute; left: -9999px; top: 0; background: var(--lime); color: var(--lime-ink); padding: 10px 16px; border-radius: 0 0 8px 0; z-index: 50; font-family: var(--mono); font-size: 0.85rem; }
.skip-link:focus { left: 0; }
.topbar { border-bottom: 1px solid var(--line); padding: 14px 0; }
.topbar-inner { display: flex; justify-content: space-between; align-items: center; }
.back { font-family: var(--mono); font-size: 0.85rem; text-decoration: none; color: var(--muted); }
.back:hover { color: var(--lime); }
.tool-tag { font-family: var(--mono); font-size: 0.75rem; color: var(--faint); text-transform: uppercase; letter-spacing: 0.1em; }
.head { padding: 40px 0 26px; }
h1 { font-family: var(--serif); font-size: clamp(2.2rem, 5vw, 3.2rem); letter-spacing: -0.02em; line-height: 1.05; }
h1 em { font-style: italic; color: var(--lime); }
.sub { color: var(--muted); margin-top: 8px; max-width: 60ch; }
h2 { font-family: var(--mono); font-size: 0.75rem; text-transform: uppercase; letter-spacing: 0.14em; color: var(--faint); margin: 0; }
.mono { font-family: var(--mono); }
.count-pill { background: var(--lime); color: var(--lime-ink); border-radius: 999px; font-family: var(--mono); font-size: 0.75rem; font-weight: 700; padding: 2px 12px; }
.panel { background: var(--surface); border: 1px solid var(--line); border-radius: 14px; padding: 26px; margin-bottom: 22px; }
.status { border-top: 3px solid var(--lime); }
.status p { color: var(--muted); margin: 10px 0 16px; max-width: 62ch; }
.label-row { display: flex; justify-content: space-between; align-items: center; margin-bottom: 6px; }
.topic-list { list-style: none; }
.topic-list li { display: flex; justify-content: space-between; padding: 8px 2px; border-top: 1px solid var(--line-soft); font-family: var(--mono); font-size: 0.85rem; color: var(--muted); }
.next-list { margin: 10px 0 16px 20px; color: var(--muted); }
.next-list li { margin-bottom: 6px; }
.foot-note { color: var(--faint); font-size: 0.9rem; }
.foot-note a { color: var(--muted); }
.foot { padding: 18px 28px 40px; color: var(--faint); font-family: var(--mono); font-size: 0.78rem; }
.filters label { display: flex; flex-direction: column; gap: 6px; font-family: var(--mono); font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.12em; color: var(--faint); }
.filters select, .filters input[type="search"] { font-family: var(--sans); font-size: 0.95rem; color: var(--ink); background: var(--surface2); border: 1px solid var(--line); border-radius: 9px; padding: 10px 12px; }
.filters select:focus, .filters input[type="search"]:focus { outline: none; border-color: var(--lime); }
.filter-row { display: flex; gap: 14px; align-items: flex-end; flex-wrap: wrap; margin-bottom: 14px; }
.filter-row:last-child { margin-bottom: 0; }
.filter-row .grow { flex: 1; min-width: 200px; }
.checks { align-items: center; }
.check { flex-direction: row !important; align-items: center; gap: 8px !important; text-transform: none !important; letter-spacing: 0 !important; font-size: 0.85rem !important; color: var(--muted) !important; cursor: pointer; }
.check input { accent-color: var(--lime); width: 1rem; height: 1rem; }
.spacer { flex: 1; }
.progress { font-family: var(--mono); font-size: 0.8rem; color: var(--muted); }
.btn { font-family: var(--mono); font-size: 0.85rem; padding: 11px 18px; border-radius: 9px; border: 1px solid var(--line); background: transparent; color: var(--ink); cursor: pointer; }
.btn:hover { border-color: var(--lime); color: var(--lime); }
.btn.solid { background: var(--lime); border-color: var(--lime); color: var(--lime-ink); font-weight: 700; }
.btn.solid:hover { color: var(--lime-ink); }
.btn.big { font-size: 1.05rem; padding: 15px 40px; }
.btn.sm { padding: 8px 14px; font-size: 0.78rem; }
.btn:disabled { opacity: 0.5; cursor: default; }
.btn.warn { border-color: var(--amber); color: var(--amber); }
a.btn { display: inline-block; text-decoration: none; align-self: center; }
.card-meta { display: flex; gap: 8px; flex-wrap: wrap; margin: 8px 0 4px; }
.pill { font-family: var(--mono); font-size: 0.72rem; border: 1px solid var(--line); border-radius: 999px; padding: 2px 12px; color: var(--muted); }
.statement { font-family: var(--serif); font-size: 1.12rem; margin-top: 10px; }
.statement p { margin-bottom: 12px; }
.statement ol, .statement ul { margin: 10px 0 14px 26px; }
.statement li { margin-bottom: 8px; }
.statement .center { text-align: center; }
.empty { color: var(--faint); font-family: var(--sans); font-size: 0.95rem; }
.faint { color: var(--faint); }
.hints { margin-top: 14px; }
.hint-bar { margin-bottom: 4px; }
.hint { border-left: 2px solid var(--lime); padding: 10px 14px; margin: 10px 0; background: var(--surface2); border-radius: 0 9px 9px 0; font-size: 1.02rem; }
.solution-wrap { margin-top: 16px; }
.solution { border: 1px solid var(--line); border-radius: 9px; padding: 16px 18px; background: var(--surface2); font-size: 1.02rem; }
.solution p { margin-bottom: 10px; }
.solution ol, .solution ul { margin: 8px 0 12px 24px; }
.solution li { margin-bottom: 6px; }
.fig-missing { font-family: var(--mono); font-size: 0.8rem; color: var(--amber); }
.card-actions { display: flex; gap: 10px; margin-top: 18px; }
.kbd { font-family: var(--mono); font-size: 0.72rem; border: 1px solid var(--line); border-bottom-width: 2px; border-radius: 6px; padding: 1px 8px; background: var(--surface); color: var(--muted); }
@media (max-width: 640px) { .panel { padding: 20px; } .btn.big { width: 100%; } }