/* Bedrock, layout and components */

/* ---------- Top bar ---------- */
.topbar {
  position: sticky; top: 0; z-index: 40;
  height: var(--topbar-h);
  display: flex; align-items: center; gap: .5rem;
  padding: 0 .75rem;
  padding-left: max(.75rem, env(safe-area-inset-left));
  padding-right: max(.75rem, env(safe-area-inset-right));
  background: color-mix(in srgb, var(--surface) 88%, transparent);
  backdrop-filter: saturate(1.4) blur(12px);
  -webkit-backdrop-filter: saturate(1.4) blur(12px);
  border-bottom: 1px solid var(--line);
}
.brand { display: flex; align-items: center; gap: .55rem; text-decoration: none; color: var(--ink); min-width: 0; }
.brand-mark {
  display: grid; place-items: center;
  width: 32px; height: 32px; flex: none;
  border-radius: 9px;
  background: linear-gradient(140deg, var(--primary), var(--accent));
  color: #fff; font-family: var(--mono); font-size: 13px; font-weight: 700;
  letter-spacing: -.5px;
}
.brand-text { display: flex; flex-direction: column; min-width: 0; }
.brand-name { font-weight: 750; font-size: 1rem; line-height: 1.15; letter-spacing: -.02em; }
.brand-sub { font-size: .7rem; color: var(--muted); line-height: 1.15; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.topbar-right { margin-left: auto; display: flex; align-items: center; gap: .4rem; }

.icon-btn {
  display: grid; place-items: center;
  width: 40px; height: 40px; flex: none;
  background: transparent; border: 1px solid transparent; border-radius: 11px;
  color: var(--ink-2);
}
.icon-btn:hover { background: var(--surface-3); color: var(--ink); }
.icon-btn svg { width: 21px; height: 21px; }

#themeToggle .i-moon { display: none; }
html[data-theme="dark"] #themeToggle .i-sun { display: none; }
html[data-theme="dark"] #themeToggle .i-moon { display: block; }

.xp-chip {
  display: inline-flex; align-items: center; gap: .3rem;
  height: 34px; padding: 0 .7rem;
  background: var(--warn-soft); color: var(--warn);
  border-radius: 999px; font-weight: 700; font-size: .85rem;
  text-decoration: none; font-variant-numeric: tabular-nums;
}
.xp-chip .xp-icon { width: 15px; height: 15px; fill: currentColor; stroke: none; }

/* ---------- Layout ---------- */
.layout { display: flex; align-items: flex-start; }

.sidebar {
  position: sticky; top: var(--topbar-h);
  width: var(--sidebar-w); flex: none;
  height: calc(100dvh - var(--topbar-h));
  overflow-y: auto; overscroll-behavior: contain;
  padding: 1rem .7rem 4rem;
  border-right: 1px solid var(--line);
  background: var(--surface);
}
.main {
  flex: 1 1 auto; min-width: 0;
  padding: 1.6rem clamp(1rem, 3vw, 2.4rem) 6rem;
  outline: none;
}
.wrap { max-width: var(--maxw); margin: 0 auto; }
.wrap-wide { max-width: 1000px; margin: 0 auto; }

.scrim {
  position: fixed; inset: 0; z-index: 44;
  background: rgba(10, 14, 30, .48);
  backdrop-filter: blur(2px);
}

@media (max-width: 900px) {
  .sidebar {
    position: fixed; z-index: 45; top: 0; left: 0; bottom: 0;
    height: 100dvh; width: min(86vw, 330px);
    transform: translateX(-102%);
    transition: transform .22s ease;
    box-shadow: var(--shadow-2);
    padding-top: calc(env(safe-area-inset-top) + .8rem);
  }
  .sidebar.open { transform: none; }
  .main { padding: 1.1rem 1rem 6rem; }
}
@media (min-width: 901px) {
  #navToggle { display: none; }
  .scrim { display: none !important; }
}

/* ---------- Sidebar content ---------- */
.side-head {
  display: flex; align-items: center; justify-content: space-between;
  padding: .2rem .55rem .7rem;
}
.side-title { font-size: .72rem; text-transform: uppercase; letter-spacing: .09em; color: var(--muted); font-weight: 700; }
.side-close { display: none; }
@media (max-width: 900px) { .side-close { display: grid; } }

.side-progress { padding: 0 .55rem .9rem; }
.side-progress .meter { margin-top: .35rem; }
.side-note { font-size: .75rem; color: var(--muted); }

.unit-block { margin-bottom: .35rem; }
.unit-btn {
  display: flex; align-items: center; gap: .55rem; width: 100%;
  background: none; border: 0; text-align: left;
  padding: .5rem .55rem; border-radius: 10px;
  color: var(--ink); font-weight: 650; font-size: .9rem;
}
.unit-btn:hover { background: var(--surface-3); }
.unit-btn .chev { width: 16px; height: 16px; color: var(--muted); transition: transform .18s ease; flex: none; }
.unit-block.open .unit-btn .chev { transform: rotate(90deg); }
.unit-num {
  flex: none; width: 24px; height: 24px; border-radius: 8px;
  display: grid; place-items: center;
  background: var(--surface-3); color: var(--muted);
  font-size: .72rem; font-weight: 750; font-family: var(--mono);
}
.unit-block.done .unit-num { background: var(--ok-soft); color: var(--ok); }
.unit-btn .label { flex: 1 1 auto; min-width: 0; }
.unit-pct { font-size: .7rem; color: var(--muted); font-variant-numeric: tabular-nums; }

.lesson-list { list-style: none; margin: .1rem 0 .5rem; padding: 0 0 0 1.9rem; display: none; }
.unit-block.open .lesson-list { display: block; }
.lesson-list a {
  display: flex; align-items: center; gap: .45rem;
  padding: .38rem .5rem; border-radius: 9px;
  color: var(--ink-2); text-decoration: none; font-size: .855rem; line-height: 1.35;
}
.lesson-list a:hover { background: var(--surface-3); color: var(--ink); }
.lesson-list a.active { background: var(--primary-soft); color: var(--primary); font-weight: 650; }
.dot {
  flex: none; width: 8px; height: 8px; border-radius: 50%;
  border: 1.5px solid var(--line-strong); background: transparent;
}
.dot.part { background: var(--warn); border-color: var(--warn); }
.dot.done { background: var(--ok); border-color: var(--ok); }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: .45rem;
  padding: .62rem 1.05rem; min-height: 44px;
  border-radius: 12px; border: 1px solid var(--line-strong);
  background: var(--surface); color: var(--ink);
  font-weight: 650; font-size: .95rem; text-decoration: none;
  transition: transform .06s ease, background .15s ease, border-color .15s ease;
}
.btn:hover { background: var(--surface-3); }
.btn:active { transform: translateY(1px); }
.btn[disabled] { opacity: .5; cursor: not-allowed; }
.btn svg { width: 18px; height: 18px; }
.btn-primary { background: var(--primary); border-color: var(--primary); color: var(--primary-ink); }
.btn-primary:hover { background: var(--primary-strong); border-color: var(--primary-strong); color: var(--primary-ink); }
.btn-ghost { background: transparent; border-color: transparent; color: var(--muted); }
.btn-ghost:hover { background: var(--surface-3); color: var(--ink); }
.btn-sm { padding: .38rem .7rem; min-height: 36px; font-size: .84rem; border-radius: 10px; }
.btn-danger { color: var(--bad); border-color: color-mix(in srgb, var(--bad) 35%, transparent); }
.btn-row { display: flex; flex-wrap: wrap; gap: .55rem; align-items: center; }

/* ---------- Cards, meters, chips ---------- */
.card {
  background: var(--surface); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 1.15rem 1.2rem;
  box-shadow: var(--shadow-1);
}
.meter { height: 8px; border-radius: 99px; background: var(--surface-3); overflow: hidden; }
.meter > i { display: block; height: 100%; border-radius: 99px; background: linear-gradient(90deg, var(--primary), var(--accent)); transition: width .4s ease; }
.chip {
  display: inline-flex; align-items: center; gap: .3rem;
  font-size: .72rem; font-weight: 700; letter-spacing: .02em;
  padding: .2rem .55rem; border-radius: 999px;
  background: var(--surface-3); color: var(--muted);
  text-transform: uppercase;
}
.chip-ok { background: var(--ok-soft); color: var(--ok); }
.chip-bad { background: var(--bad-soft); color: var(--bad); }
.chip-warn { background: var(--warn-soft); color: var(--warn); }
.chip-info { background: var(--info-soft); color: var(--info); }
.chip-accent { background: var(--accent-soft); color: var(--accent); }

/* ---------- Home ---------- */
.hero {
  position: relative; overflow: hidden;
  border-radius: var(--radius-lg);
  padding: clamp(1.4rem, 4vw, 2.4rem);
  background: linear-gradient(135deg, #4c5fd5 0%, #6b4fd8 55%, #f2601f 160%);
  color: #fff; box-shadow: var(--shadow-2);
}
.hero::after {
  content: ""; position: absolute; right: -60px; top: -70px;
  width: 240px; height: 240px; border-radius: 50%;
  background: rgba(255, 255, 255, .1);
}
.hero h1 { color: #fff; margin-bottom: .35rem; }
.hero p { color: rgba(255, 255, 255, .9); max-width: 46ch; margin-bottom: 1.1rem; }
.hero .btn { background: #fff; border-color: #fff; color: #2a3170; }
.hero .btn-outline { background: rgba(255,255,255,.12); border-color: rgba(255,255,255,.55); color: #fff; }
.hero-meta { display: flex; gap: 1.4rem; flex-wrap: wrap; margin-top: 1.3rem; position: relative; }
.hero-meta div { font-size: .78rem; color: rgba(255,255,255,.78); }
.hero-meta b { display: block; font-size: 1.35rem; color: #fff; font-variant-numeric: tabular-nums; }

.countdown {
  display: flex; align-items: center; gap: .6rem;
  margin: 1.1rem 0 0; padding: .7rem .9rem;
  border-radius: 12px; background: rgba(255,255,255,.14);
  border: 1px solid rgba(255,255,255,.25);
  font-size: .88rem; position: relative;
}

.unit-grid { display: grid; gap: .85rem; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); }
.unit-card {
  display: flex; flex-direction: column; gap: .5rem;
  padding: 1rem 1.05rem; border-radius: var(--radius);
  background: var(--surface); border: 1px solid var(--line);
  text-decoration: none; color: var(--ink);
  box-shadow: var(--shadow-1);
  transition: transform .12s ease, box-shadow .12s ease, border-color .12s ease;
}
.unit-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-2); border-color: var(--line-strong); color: var(--ink); }
.unit-card .top { display: flex; align-items: center; gap: .6rem; }
.unit-card .badge {
  width: 34px; height: 34px; border-radius: 10px; flex: none;
  display: grid; place-items: center; font-weight: 750; font-family: var(--mono); font-size: .82rem;
  background: var(--primary-soft); color: var(--primary);
}
.unit-card h3 { margin: 0; font-size: 1rem; }
.unit-card p { margin: 0; font-size: .85rem; color: var(--muted); line-height: 1.45; }
.unit-card .foot { margin-top: auto; padding-top: .35rem; display: flex; align-items: center; gap: .55rem; font-size: .75rem; color: var(--muted); }
.unit-card .meter { flex: 1 1 auto; }

/* ---------- Lesson content ---------- */
.lesson-head { margin-bottom: 1.4rem; }
.crumb { font-size: .78rem; color: var(--muted); font-weight: 650; letter-spacing: .02em; margin-bottom: .3rem; }
.lesson-head h1 { margin-bottom: .3rem; }
.lede { font-size: 1.06rem; color: var(--ink-2); }

.keyline {
  border-left: 4px solid var(--accent);
  background: var(--accent-soft);
  padding: .85rem 1rem; border-radius: 0 12px 12px 0;
  margin: 1.3rem 0; font-size: 1rem;
}
.keyline b { color: var(--ink); }

.callout {
  display: flex; gap: .75rem;
  border: 1px solid var(--line); border-radius: var(--radius);
  padding: .9rem 1rem; margin: 1.3rem 0;
  background: var(--surface);
}
.callout .ic { flex: none; width: 24px; height: 24px; display: grid; place-items: center; border-radius: 8px; }
.callout .ic svg { width: 16px; height: 16px; }
.callout .body { min-width: 0; }
.callout .body > :last-child { margin-bottom: 0; }
.callout h4 { margin: 0 0 .25rem; font-size: .95rem; }
.callout.tip { background: var(--info-soft); border-color: color-mix(in srgb, var(--info) 25%, transparent); }
.callout.tip .ic { background: var(--info); color: #fff; }
.callout.warn { background: var(--warn-soft); border-color: color-mix(in srgb, var(--warn) 30%, transparent); }
.callout.warn .ic { background: var(--warn); color: #fff; }
.callout.trap { background: var(--bad-soft); border-color: color-mix(in srgb, var(--bad) 28%, transparent); }
.callout.trap .ic { background: var(--bad); color: #fff; }
.callout.win { background: var(--ok-soft); border-color: color-mix(in srgb, var(--ok) 28%, transparent); }
.callout.win .ic { background: var(--ok); color: #fff; }

.tbl-wrap { overflow-x: auto; margin: 1.2rem 0; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); }
table { border-collapse: collapse; width: 100%; font-size: .9rem; }
th, td { text-align: left; padding: .6rem .8rem; border-bottom: 1px solid var(--line); vertical-align: top; }
th { background: var(--surface-2); font-size: .76rem; text-transform: uppercase; letter-spacing: .05em; color: var(--muted); white-space: nowrap; }
tr:last-child td { border-bottom: 0; }
td code { white-space: pre; }

.compare { display: grid; gap: .8rem; grid-template-columns: 1fr 1fr; margin: 1.3rem 0; }
@media (max-width: 640px) { .compare { grid-template-columns: 1fr; } }
.compare .col { border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; background: var(--surface); }
.compare .col header { display: flex; align-items: center; gap: .4rem; padding: .5rem .75rem; font-size: .78rem; font-weight: 750; }
.compare .bad header { background: var(--bad-soft); color: var(--bad); }
.compare .good header { background: var(--ok-soft); color: var(--ok); }
.compare .note { padding: .55rem .75rem; font-size: .82rem; color: var(--muted); border-top: 1px solid var(--line); }
.compare pre.code { margin: 0; border-radius: 0; border: 0; }

/* ---------- Code blocks ---------- */
.codewrap { margin: 1.2rem 0; }
.codewrap .cap { font-size: .8rem; color: var(--muted); margin-bottom: .35rem; }
pre.code {
  margin: 0; background: var(--code-bg); color: var(--code-ink);
  border-radius: var(--radius); border: 1px solid var(--code-line);
  padding: .9rem 1rem; overflow-x: auto;
  font-size: .875rem; line-height: 1.6; tab-size: 4;
}
pre.code code { background: none; border: 0; padding: 0; white-space: pre; font-size: inherit; color: inherit; }
.tok-kw { color: var(--code-kw); }
.tok-str { color: var(--code-str); }
.tok-num { color: var(--code-num); }
.tok-fn { color: var(--code-fn); }
.tok-com { color: var(--code-com); font-style: italic; }
.tok-op { color: var(--code-op); }

.runbar {
  display: flex; align-items: center; gap: .5rem; flex-wrap: wrap;
  margin-top: .5rem;
}
.io-block {
  margin-top: .5rem; border: 1px solid var(--line); border-radius: var(--radius-sm);
  background: var(--surface-2); overflow: hidden;
}
.io-block .io-head {
  font-size: .7rem; text-transform: uppercase; letter-spacing: .07em; font-weight: 750;
  color: var(--muted); padding: .4rem .7rem; border-bottom: 1px solid var(--line); background: var(--surface-3);
}
.io-block pre { margin: 0; padding: .6rem .75rem; font-size: .85rem; white-space: pre-wrap; overflow-x: auto; }
.io-block pre.err { color: var(--bad); }

/* ---------- Exercise shell ---------- */
.ex {
  border: 1px solid var(--line); border-radius: var(--radius);
  background: var(--surface); box-shadow: var(--shadow-1);
  margin: 1.5rem 0; overflow: hidden;
}
.ex-head {
  display: flex; align-items: center; gap: .5rem; flex-wrap: wrap;
  padding: .7rem .95rem; border-bottom: 1px solid var(--line);
  background: var(--surface-2);
}
.ex-head .n { font-size: .78rem; font-weight: 750; color: var(--muted); font-variant-numeric: tabular-nums; }
.ex-head .xp { margin-left: auto; font-size: .72rem; color: var(--muted); font-weight: 700; }
.ex-body { padding: 1rem .95rem 1.05rem; }
.ex-body > :first-child { margin-top: 0; }
.ex.solved { border-color: color-mix(in srgb, var(--ok) 45%, var(--line)); }
.ex.solved .ex-head { background: var(--ok-soft); }
.q-text { font-weight: 600; margin-bottom: .8rem; }

/* Choices */
.choices { display: grid; gap: .5rem; margin-bottom: .9rem; }
.choice {
  display: flex; align-items: flex-start; gap: .65rem;
  padding: .7rem .8rem; border: 1.5px solid var(--line); border-radius: 12px;
  background: var(--surface); text-align: left; width: 100%;
  font-size: .95rem; line-height: 1.45; color: var(--ink);
}
.choice:hover:not([disabled]) { border-color: var(--primary); background: var(--primary-soft); }
.choice .k {
  flex: none; width: 24px; height: 24px; border-radius: 7px;
  display: grid; place-items: center; font-size: .75rem; font-weight: 750;
  background: var(--surface-3); color: var(--muted); font-family: var(--mono);
}
.choice.sel { border-color: var(--primary); background: var(--primary-soft); }
.choice.sel .k { background: var(--primary); color: var(--primary-ink); }
.choice.right { border-color: var(--ok); background: var(--ok-soft); }
.choice.right .k { background: var(--ok); color: #fff; }
.choice.wrong { border-color: var(--bad); background: var(--bad-soft); }
.choice.wrong .k { background: var(--bad); color: #fff; }
.choice code { background: color-mix(in srgb, var(--ink) 8%, transparent); }

/* Text answer */
.ans-input {
  width: 100%; padding: .65rem .8rem; font-family: var(--mono); font-size: 16px;
  border: 1.5px solid var(--line-strong); border-radius: 12px; background: var(--surface-2);
  resize: vertical; min-height: 46px;
}
.ans-input:focus { border-color: var(--primary); }

/* Feedback */
.fb { display: none; gap: .6rem; margin-top: .9rem; padding: .8rem .9rem; border-radius: 12px; font-size: .93rem; }
.fb.show { display: flex; }
.fb .ic { flex: none; width: 22px; height: 22px; border-radius: 50%; display: grid; place-items: center; }
.fb .ic svg { width: 14px; height: 14px; stroke-width: 2.6; }
.fb.ok { background: var(--ok-soft); color: var(--ok); }
.fb.ok .ic { background: var(--ok); color: #fff; }
.fb.no { background: var(--bad-soft); color: var(--bad); }
.fb.no .ic { background: var(--bad); color: #fff; }
.fb .txt { color: var(--ink-2); }
.fb .txt b { color: inherit; }
.fb.ok .txt strong, .fb.no .txt strong { color: var(--ink); }
.fb .txt > :last-child { margin-bottom: 0; }

.reveal { margin-top: .9rem; }
.reveal summary {
  cursor: pointer; font-size: .85rem; font-weight: 700; color: var(--primary);
  list-style: none; display: inline-flex; align-items: center; gap: .35rem;
  padding: .45rem .7rem; border-radius: 10px; background: var(--primary-soft);
}
.reveal summary::-webkit-details-marker { display: none; }
.reveal[open] summary { margin-bottom: .6rem; }
.reveal .rv-body { border-left: 3px solid var(--primary-soft); padding-left: .9rem; }
.locked-note { font-size: .82rem; color: var(--muted); margin-top: .8rem; display: flex; align-items: center; gap: .4rem; }
.locked-note svg { width: 15px; height: 15px; }

/* ---------- Code challenge ---------- */
.chal .spec { font-size: .95rem; }
.spec-grid { display: grid; gap: .5rem; margin: .9rem 0; }
.spec-row { display: grid; grid-template-columns: 90px 1fr; gap: .6rem; align-items: start; font-size: .92rem; }
@media (max-width: 560px) { .spec-row { grid-template-columns: 1fr; gap: .1rem; } }
.spec-row .k { font-size: .74rem; text-transform: uppercase; letter-spacing: .06em; color: var(--muted); font-weight: 750; padding-top: .25rem; }

.samples { display: grid; gap: .6rem; grid-template-columns: 1fr 1fr; margin: .9rem 0; }
@media (max-width: 560px) { .samples { grid-template-columns: 1fr; } }
.sample { border: 1px solid var(--line); border-radius: 10px; overflow: hidden; background: var(--surface-2); }
.sample .h { font-size: .7rem; text-transform: uppercase; letter-spacing: .06em; font-weight: 750; color: var(--muted); padding: .35rem .6rem; background: var(--surface-3); border-bottom: 1px solid var(--line); }
.sample pre { margin: 0; padding: .5rem .6rem; font-size: .85rem; white-space: pre-wrap; }

.editor-shell { border: 1px solid var(--code-line); border-radius: var(--radius); overflow: hidden; background: var(--code-bg); margin-top: .5rem; }
.editor-bar {
  display: flex; align-items: center; gap: .4rem;
  padding: .4rem .55rem; background: var(--code-bg-2); border-bottom: 1px solid var(--code-line);
}
.editor-bar .fname { font-family: var(--mono); font-size: .76rem; color: var(--code-com); margin-right: auto; padding-left: .25rem; }
.editor-bar button {
  background: transparent; border: 1px solid transparent; color: var(--code-com);
  border-radius: 8px; padding: .25rem .5rem; font-size: .74rem; font-weight: 650;
  display: inline-flex; align-items: center; gap: .25rem;
}
.editor-bar button:hover { background: rgba(255,255,255,.08); color: var(--code-ink); }
.editor-bar button svg { width: 14px; height: 14px; }

.editor {
  position: relative;
  font-family: var(--mono); font-size: 14px; line-height: 1.65;
}
/* iOS zooms the page when a focused field is under 16px, so keep phones at 16. */
@media (max-width: 900px) { .editor { font-size: 16px; } }
.editor .hl, .editor textarea {
  margin: 0; padding: .8rem .9rem;
  font: inherit; letter-spacing: normal;
  white-space: pre-wrap; overflow-wrap: break-word; word-break: normal;
  tab-size: 4;
}
.editor .hl {
  position: absolute; inset: 0; pointer-events: none;
  color: var(--code-ink); overflow: hidden;
}
.editor textarea {
  position: relative; display: block; width: 100%;
  min-height: 168px; border: 0; outline: none; resize: vertical;
  background: transparent; color: transparent; caret-color: #fff;
  -webkit-text-fill-color: transparent;
  overflow: hidden;
}
.editor textarea::selection { background: rgba(128, 145, 255, .35); }
.editor textarea::placeholder { color: var(--code-com); -webkit-text-fill-color: var(--code-com); }

.keypad {
  display: flex; gap: .3rem; overflow-x: auto; padding: .45rem .5rem;
  background: var(--code-bg-2); border-top: 1px solid var(--code-line);
  scrollbar-width: none;
}
.keypad::-webkit-scrollbar { display: none; }
.keypad button {
  flex: none; min-width: 36px; height: 34px; padding: 0 .5rem;
  background: rgba(255,255,255,.07); border: 1px solid var(--code-line);
  color: var(--code-ink); border-radius: 8px;
  font-family: var(--mono); font-size: .85rem;
}
.keypad button:active { background: rgba(255,255,255,.2); }
@media (min-width: 901px) { .keypad { display: none; } }

.chal-actions { display: flex; gap: .5rem; align-items: center; flex-wrap: wrap; margin-top: .7rem; }
.chal-actions .grow { flex: 1 1 auto; }

.tests { margin-top: .85rem; display: grid; gap: .45rem; }
.test {
  border: 1px solid var(--line); border-radius: 10px; overflow: hidden; background: var(--surface-2);
}
.test > summary {
  display: flex; align-items: center; gap: .5rem; cursor: pointer;
  padding: .5rem .7rem; font-size: .85rem; font-weight: 650; list-style: none;
}
.test > summary::-webkit-details-marker { display: none; }
.test .st { flex: none; width: 20px; height: 20px; border-radius: 50%; display: grid; place-items: center; background: var(--surface-3); color: var(--muted); }
.test .st svg { width: 13px; height: 13px; stroke-width: 2.6; }
.test.pass .st { background: var(--ok); color: #fff; }
.test.fail .st { background: var(--bad); color: #fff; }
.test.pass { border-color: color-mix(in srgb, var(--ok) 35%, var(--line)); }
.test.fail { border-color: color-mix(in srgb, var(--bad) 35%, var(--line)); }
.test .meta { margin-left: auto; font-size: .72rem; color: var(--muted); font-weight: 600; }
.test .detail { padding: .1rem .7rem .7rem; display: grid; gap: .5rem; grid-template-columns: 1fr 1fr; }
@media (max-width: 560px) { .test .detail { grid-template-columns: 1fr; } }
.test .detail .box { border: 1px solid var(--line); border-radius: 8px; background: var(--surface); overflow: hidden; }
.test .detail .box .h { font-size: .68rem; text-transform: uppercase; letter-spacing: .06em; color: var(--muted); font-weight: 750; padding: .3rem .55rem; border-bottom: 1px solid var(--line); }
.test .detail .box pre { margin: 0; padding: .45rem .55rem; font-size: .82rem; white-space: pre-wrap; min-height: 1.8em; }
.test .detail .box pre .ws { color: var(--bad); opacity: .75; }
.test .detail .box pre .empty { color: var(--muted); font-style: italic; }

.verdict { margin-top: .8rem; padding: .75rem .9rem; border-radius: 12px; font-size: .93rem; display: flex; gap: .6rem; align-items: flex-start; }
.verdict.ok { background: var(--ok-soft); color: var(--ok); }
.verdict.no { background: var(--bad-soft); color: var(--bad); }
.verdict .txt { color: var(--ink-2); }
.verdict .txt b { color: var(--ink); }

/* ---------- Lesson footer nav ---------- */
.lesson-nav { display: flex; gap: .7rem; margin-top: 2.6rem; padding-top: 1.4rem; border-top: 1px solid var(--line); }
.lesson-nav a { flex: 1 1 0; min-width: 0; display: flex; flex-direction: column; gap: .15rem; padding: .8rem 1rem; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); text-decoration: none; }
.lesson-nav a:hover { border-color: var(--primary); }
.lesson-nav .dir { font-size: .7rem; text-transform: uppercase; letter-spacing: .07em; color: var(--muted); font-weight: 750; }
.lesson-nav .t { font-weight: 650; color: var(--ink); font-size: .92rem; }
.lesson-nav .next { text-align: right; align-items: flex-end; }

.done-bar {
  position: sticky; bottom: 0; z-index: 20;
  margin: 2rem -1rem -6rem; padding: .7rem 1rem;
  padding-bottom: calc(.7rem + env(safe-area-inset-bottom));
  background: color-mix(in srgb, var(--surface) 92%, transparent);
  backdrop-filter: blur(10px); border-top: 1px solid var(--line);
  display: flex; align-items: center; gap: .7rem;
}
.done-bar .info { font-size: .82rem; color: var(--muted); flex: 1 1 auto; }
.done-bar .info b { color: var(--ink); }

/* ---------- Python status pill ---------- */
.py-status {
  position: fixed; z-index: 50; left: 50%; transform: translateX(-50%);
  bottom: calc(1rem + env(safe-area-inset-bottom));
  display: flex; align-items: center; gap: .5rem;
  padding: .5rem .9rem; border-radius: 999px;
  background: var(--ink); color: var(--surface);
  font-size: .82rem; font-weight: 600; box-shadow: var(--shadow-2);
}
.spinner {
  width: 14px; height: 14px; border-radius: 50%; flex: none;
  border: 2px solid color-mix(in srgb, var(--surface) 35%, transparent);
  border-top-color: var(--surface);
  animation: spin .7s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ---------- Mock activity ---------- */
.timer-bar {
  position: sticky; top: var(--topbar-h); z-index: 30;
  display: flex; align-items: center; gap: .7rem;
  margin: 0 0 1.2rem; padding: .6rem .9rem;
  border-radius: 12px; border: 1px solid var(--line);
  background: var(--surface); box-shadow: var(--shadow-1);
}
.timer-bar .time { font-family: var(--mono); font-size: 1.2rem; font-weight: 700; font-variant-numeric: tabular-nums; }
.timer-bar.low .time { color: var(--bad); }
.timer-bar .lbl { font-size: .78rem; color: var(--muted); }

/* ---------- Misc ---------- */
.stat-row { display: grid; gap: .7rem; grid-template-columns: repeat(auto-fit, minmax(130px, 1fr)); margin: 1.2rem 0; }
.stat { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: .8rem .9rem; }
.stat b { display: block; font-size: 1.5rem; line-height: 1.2; font-variant-numeric: tabular-nums; }
.stat span { font-size: .76rem; color: var(--muted); }

.section-title { display: flex; align-items: baseline; gap: .6rem; margin: 2.2rem 0 1rem; }
.section-title h2 { margin: 0; }
.section-title .sub { font-size: .82rem; color: var(--muted); }

.pill-row { display: flex; flex-wrap: wrap; gap: .4rem; margin: .8rem 0 1.2rem; }

.toast {
  position: fixed; left: 50%; bottom: calc(4.2rem + env(safe-area-inset-bottom));
  transform: translate(-50%, 12px); z-index: 60;
  background: var(--ok); color: #fff; font-weight: 650; font-size: .9rem;
  padding: .6rem 1rem; border-radius: 999px; box-shadow: var(--shadow-2);
  opacity: 0; transition: opacity .2s ease, transform .2s ease; pointer-events: none;
}
.toast.show { opacity: 1; transform: translate(-50%, 0); }