/* ============================================================
   Quiz — Tonal Monochrome design system (Geist-derived tokens)
   L0 page(grid canvas) → L1 surface → L2 raised → L3 floating
   Border-first. Text is always grayscale. Color = verdict only.
   ============================================================ */

/* ---------- Tokens(全站仅白色主题) ---------- */
:root {
  color-scheme: light;
  --bg-100: #ffffff;                 /* L1 surface */
  --bg-200: #fafafa;                 /* L0 page canvas */
  --gray-100: hsl(0, 0%, 95%);
  --gray-200: hsl(0, 0%, 92%);
  --gray-300: hsl(0, 0%, 90%);
  --gray-500: hsl(0, 0%, 79%);
  --gray-600: hsl(0, 0%, 66%);
  --gray-700: hsl(0, 0%, 56%);
  --gray-800: hsl(0, 0%, 49%);
  --gray-900: hsl(0, 0%, 30%);
  --gray-1000: hsl(0, 0%, 9%);
  --gray-a100: #0000000d;
  --gray-a200: #00000015;
  --gray-a300: #0000001a;
  --gray-a500: #00000036;
  --grid-line: #0000000a;
  --green: hsl(131, 41%, 40%);
  --green-tint: hsl(131, 41%, 46%, 0.07);
  --red: hsl(358, 66%, 48%);
  --red-tint: hsl(358, 75%, 59%, 0.06);
  --shadow-menu: 0 0 0 1px #00000014, 0px 4px 8px -4px #0000000a, 0px 16px 24px -8px #0000000f;
  --fg: var(--gray-1000);
  --fg-inverse: #ffffff;
}
:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
  --radius-sm: 5px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --maxw: 720px;
}

/* ---------- Base ---------- */
* { box-sizing: border-box; }
html { background: var(--bg-200); scrollbar-gutter: stable; }
html, body { margin: 0; padding: 0; }
body {
  color: var(--gray-1000);
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

/* Engineering line-grid canvas — L0 texture, fades toward bottom */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 56px 56px;
  -webkit-mask-image: linear-gradient(180deg, black 0%, black 45%, transparent 95%);
          mask-image: linear-gradient(180deg, black 0%, black 45%, transparent 95%);
}

button { font-family: inherit; font-size: inherit; cursor: pointer; color: inherit; background: none; border: none; padding: 0; }
a { color: inherit; }
::selection { background: var(--gray-a300); }

::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--gray-a300); border-radius: 3px; }

:focus-visible { outline: 2px solid var(--gray-1000); outline-offset: 2px; border-radius: var(--radius-sm); }

.mono { font-family: var(--font-mono); font-variant-numeric: tabular-nums; }

/* ---------- Topbar ---------- */
.topbar {
  position: sticky; top: 0; z-index: 20;
  display: flex; align-items: center; gap: 12px;
  height: 56px;
  padding: 0 24px;
  background: color-mix(in srgb, var(--bg-200) 78%, transparent);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--gray-a200);
}
.brand {
  display: flex; align-items: center; gap: 10px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.01em;
  color: var(--gray-1000);
}
.brand .dot { width: 10px; height: 10px; border-radius: 3px; background: var(--gray-1000); }
.brand .sep { color: var(--gray-600); }
.brand .dim { color: var(--gray-800); }
.topbar .spacer { flex: 1; }
.icon-btn {
  display: inline-flex; align-items: center; justify-content: center;
  width: 32px; height: 32px;
  border-radius: var(--radius-md);
  color: var(--gray-800);
  transition: color 120ms ease, background-color 120ms ease;
}
.icon-btn:hover { color: var(--gray-1000); background: var(--gray-a100); }
.icon-btn svg { width: 16px; height: 16px; }

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 48px 24px 96px; }

/* ---------- Home ---------- */
.hero { margin: 8px 0 40px; }
.hero .kicker {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--gray-700);
}
.hero h1 {
  margin: 12px 0 10px;
  font-size: 34px;
  line-height: 1.15;
  font-weight: 600;
  letter-spacing: -0.03em;
  color: var(--gray-1000);
}
.hero p { margin: 0; font-size: 15px; color: var(--gray-800); }

/* stats — one L1 surface, hairline dividers */
.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border: 1px solid var(--gray-a200);
  border-radius: var(--radius-lg);
  background: var(--bg-100);
  overflow: hidden;
}
.stat { padding: 18px 20px 16px; }
.stat + .stat { border-left: 1px solid var(--gray-a100); }
.stat .l {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--gray-700);
  margin-bottom: 6px;
}
.stat .n {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 26px;
  line-height: 1.1;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--gray-1000);
}
.stat .n .sub { font-size: 13px; font-weight: 400; color: var(--gray-600); margin-left: 2px; }

.progress-row { display: flex; align-items: center; gap: 12px; margin: 20px 2px 40px; }
.progress-bar {
  flex: 1; height: 3px;
  background: var(--gray-a200);
  border-radius: 2px;
  overflow: hidden;
}
.progress-bar > div { height: 100%; background: var(--gray-1000); border-radius: 2px; transition: width 400ms ease-out; }
.progress-row .pct { font-family: var(--font-mono); font-size: 11px; color: var(--gray-700); font-variant-numeric: tabular-nums; }

/* actions — one primary, rest quiet */
.actions { display: flex; gap: 10px; flex-wrap: wrap; }
.action {
  display: inline-flex; align-items: center; gap: 8px;
  height: 40px;
  padding: 0 18px;
  border-radius: var(--radius-md);
  border: 1px solid var(--gray-a300);
  background: var(--bg-100);
  font-size: 14px;
  font-weight: 500;
  color: var(--gray-900);
  transition: background-color 120ms ease, border-color 120ms ease, transform 100ms ease-out;
}
.action:hover { background: var(--gray-100); border-color: var(--gray-a500); }
.action:active { transform: scale(0.98); }
.action.primary {
  background: var(--gray-1000);
  border-color: var(--gray-1000);
  color: var(--fg-inverse);
}
.action.primary:hover { opacity: 0.88; background: var(--gray-1000); }
.action:disabled { opacity: 0.4; cursor: not-allowed; }
.action:disabled:hover { background: var(--bg-100); border-color: var(--gray-a300); }
.action.primary:disabled:hover { background: var(--gray-1000); }
.action .count {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--gray-700);
  font-variant-numeric: tabular-nums;
}
.action.primary .count { color: color-mix(in srgb, var(--fg-inverse) 60%, transparent); }
.action svg { width: 14px; height: 14px; }

.section-title {
  margin: 48px 0 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--gray-700);
}
.concepts { display: flex; flex-wrap: wrap; gap: 8px; }
.chip {
  display: inline-flex; align-items: center; gap: 6px;
  height: 28px;
  padding: 0 12px;
  border-radius: 999px;
  border: 1px solid var(--gray-a200);
  background: var(--bg-100);
  font-size: 12.5px;
  color: var(--gray-900);
  transition: border-color 120ms ease, background-color 120ms ease;
}
.chip:hover { border-color: var(--gray-a500); background: var(--gray-100); }
.chip .c { font-family: var(--font-mono); font-size: 10.5px; color: var(--gray-600); font-variant-numeric: tabular-nums; }
.chip.more { color: var(--gray-700); border-style: dashed; }

.manage-row { margin-top: 12px; }
.link-quiet {
  font-size: 12.5px;
  color: var(--gray-700);
  transition: color 120ms ease;
}
.link-quiet:hover { color: var(--red); }

/* ---------- Quiz ---------- */
.quiz-meta {
  display: flex; align-items: baseline; gap: 10px;
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--gray-700);
}
.quiz-meta .qcounter { color: var(--gray-1000); font-variant-numeric: tabular-nums; }
.quiz-meta .sep { color: var(--gray-500); }
.quiz-meta .spacer { flex: 1; }
.quiz-meta .tag { color: var(--gray-700); }
.quiz-meta .multi-flag { color: var(--gray-1000); border: 1px solid var(--gray-a300); border-radius: 4px; padding: 1px 7px; font-size: 10.5px; }

.session-bar { height: 2px; background: var(--gray-a200); border-radius: 1px; overflow: hidden; margin-bottom: 24px; }
.session-bar > div { height: 100%; background: var(--gray-1000); transition: width 300ms ease-out; }

.qcard {
  background: var(--bg-100);
  border: 1px solid var(--gray-a200);
  border-radius: var(--radius-lg);
  padding: 28px;
  animation: card-in 200ms ease-out;
}
@keyframes card-in {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: none; }
}
.qhead { display: flex; align-items: flex-start; gap: 16px; }
.qtext {
  flex: 1;
  font-size: 16px;
  line-height: 1.7;
  color: var(--gray-1000);
  white-space: pre-line;
  margin: 0 0 24px;
}
.bookmark-btn {
  flex-shrink: 0;
  display: inline-flex; align-items: center; justify-content: center;
  width: 32px; height: 32px;
  margin: -6px -6px 0 0;
  border-radius: var(--radius-md);
  color: var(--gray-600);
  transition: color 120ms ease, background-color 120ms ease;
}
.bookmark-btn:hover { color: var(--gray-1000); background: var(--gray-a100); }
.bookmark-btn.on { color: var(--gray-1000); }
.bookmark-btn svg { width: 16px; height: 16px; }

/* choices */
.choices { display: flex; flex-direction: column; gap: 8px; }
.choice {
  display: flex; align-items: flex-start; gap: 12px;
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--gray-a200);
  border-radius: var(--radius-md);
  background: transparent;
  text-align: left;
  transition: background-color 120ms ease, border-color 120ms ease, transform 100ms ease-out;
}
.choice:not(.locked):hover { background: var(--gray-100); border-color: var(--gray-a300); }
.choice:not(.locked):active { transform: scale(0.99); }
.choice .key {
  flex-shrink: 0;
  display: inline-flex; align-items: center; justify-content: center;
  width: 24px; height: 24px;
  margin-top: 1px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--gray-a300);
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--gray-800);
  transition: background-color 120ms ease, color 120ms ease, border-color 120ms ease;
}
.choice .body { flex: 1; font-size: 14px; line-height: 1.6; color: var(--gray-900); padding-top: 1px; }
.choice.selected { border-color: var(--gray-1000); }
.choice.selected .key { background: var(--gray-1000); border-color: var(--gray-1000); color: var(--fg-inverse); }
.choice.locked { cursor: default; }
.choice.correct { border-color: var(--green); background: var(--green-tint); }
.choice.correct .key { background: var(--green); border-color: var(--green); color: #fff; }
.choice.correct .body { color: var(--gray-1000); }
.choice.wrong { border-color: var(--red); background: var(--red-tint); }
.choice.wrong .key { background: var(--red); border-color: var(--red); color: #fff; }
.choice .whywrong {
  margin-top: 6px;
  font-size: 12.5px;
  line-height: 1.55;
  color: var(--gray-800);
}

/* submit row */
.submit-row { display: flex; align-items: center; gap: 10px; margin-top: 24px; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  height: 36px;
  padding: 0 16px;
  border-radius: var(--radius-md);
  border: 1px solid var(--gray-a300);
  background: transparent;
  font-size: 13.5px;
  font-weight: 500;
  color: var(--gray-900);
  transition: background-color 120ms ease, border-color 120ms ease, opacity 120ms ease, transform 100ms ease-out;
}
.btn:hover { background: var(--gray-100); }
.btn:active { transform: scale(0.98); }
.btn.primary {
  background: var(--gray-1000);
  border-color: var(--gray-1000);
  color: var(--fg-inverse);
}
.btn.primary:hover { opacity: 0.88; background: var(--gray-1000); }
.btn.ghost { border-color: transparent; color: var(--gray-800); }
.btn.ghost:hover { color: var(--gray-1000); background: var(--gray-a100); }
.btn:disabled { opacity: 0.4; cursor: not-allowed; transform: none; }
.btn svg { width: 14px; height: 14px; }

.hint { margin-left: auto; display: flex; align-items: center; gap: 5px; font-size: 11.5px; color: var(--gray-600); }
kbd {
  display: inline-flex; align-items: center; justify-content: center;
  min-width: 18px; height: 18px;
  padding: 0 4px;
  border: 1px solid var(--gray-a300);
  border-bottom-width: 2px;
  border-radius: 4px;
  background: var(--bg-100);
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--gray-700);
}

/* ---------- Explanation ---------- */
.explain {
  margin-top: 24px;
  border-top: 1px solid var(--gray-a200);
  padding-top: 22px;
  animation: slide-up 250ms ease-out;
}
@keyframes slide-up {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: none; }
}
.verdict {
  display: flex; align-items: center; gap: 8px;
  font-size: 15px;
  font-weight: 600;
  letter-spacing: -0.01em;
}
.verdict.ok { color: var(--green); }
.verdict.no { color: var(--red); }
.verdict.neutral { color: var(--gray-1000); }
.verdict svg { width: 16px; height: 16px; }
.ans-line {
  display: flex; align-items: center; gap: 8px;
  margin: 10px 0 0;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--gray-700);
}
.ans-line b { color: var(--gray-1000); font-weight: 600; }
.badge {
  display: inline-flex; align-items: center;
  height: 18px;
  padding: 0 7px;
  border: 1px solid var(--gray-a300);
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.03em;
  color: var(--gray-800);
}
.explain h4 {
  margin: 22px 0 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--gray-700);
}
.explain .prose { font-size: 14px; line-height: 1.75; color: var(--gray-900); }
.src-note {
  display: flex; align-items: center; gap: 8px; flex-wrap: wrap;
  margin-top: 22px;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--gray-600);
}
.src-note a { color: var(--gray-700); text-decoration: underline; text-underline-offset: 3px; }
.src-note a:hover { color: var(--gray-1000); }

/* ---------- Bottom nav ---------- */
.navbar { display: flex; align-items: center; gap: 8px; margin-top: 20px; }
.navbar .spacer { flex: 1; }
.jump { display: flex; align-items: center; gap: 6px; font-family: var(--font-mono); font-size: 11.5px; color: var(--gray-600); }
.jump input {
  width: 52px; height: 30px;
  border: 1px solid var(--gray-a300);
  border-radius: var(--radius-sm);
  background: var(--bg-100);
  color: var(--gray-1000);
  font-family: var(--font-mono);
  font-size: 12px;
  text-align: center;
}
.jump input:focus { outline: none; border-color: var(--gray-1000); }
/* strip number spinners */
.jump input::-webkit-outer-spin-button, .jump input::-webkit-inner-spin-button { -webkit-appearance: none; margin: 0; }
.jump input[type="number"] { -moz-appearance: textfield; appearance: textfield; }

/* ---------- misc ---------- */
.empty { text-align: center; padding: 96px 20px; color: var(--gray-700); font-size: 14px; }
.toast {
  position: fixed; bottom: 24px; left: 50%;
  transform: translateX(-50%) translateY(4px);
  padding: 9px 16px;
  border: 1px solid var(--gray-a200);
  border-radius: var(--radius-md);
  background: var(--bg-100);
  box-shadow: var(--shadow-menu);
  font-size: 12.5px;
  color: var(--gray-1000);
  z-index: 50;
  opacity: 0;
  pointer-events: none;
  transition: opacity 200ms ease, transform 200ms ease;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

@media (max-width: 640px) {
  .wrap { padding: 32px 16px 80px; }
  .hero h1 { font-size: 26px; }
  .stats { grid-template-columns: repeat(2, 1fr); }
  .stat:nth-child(3), .stat:nth-child(4) { border-top: 1px solid var(--gray-a100); }
  .stat:nth-child(3) { border-left: none; }
  .qcard { padding: 20px 16px; }
  .actions .action { flex: 1 1 45%; justify-content: center; }
  .hint { display: none; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

/* ============================================================
   Mock Exam
   ============================================================ */

/* intro */
.exam-intro {
  background: var(--bg-100);
  border: 1px solid var(--gray-a200);
  border-radius: var(--radius-lg);
  padding: 32px;
}
.exam-intro h2 { margin: 0 0 6px; font-size: 22px; font-weight: 600; letter-spacing: -0.02em; color: var(--gray-1000); }
.exam-intro .sub { margin: 0 0 24px; font-size: 13.5px; color: var(--gray-800); }
.exam-specs { display: grid; grid-template-columns: repeat(4, 1fr); gap: 0; border: 1px solid var(--gray-a200); border-radius: var(--radius-md); overflow: hidden; margin-bottom: 20px; }
.exam-specs .spec { padding: 14px 16px; }
.exam-specs .spec + .spec { border-left: 1px solid var(--gray-a100); }
.exam-specs .spec .l { font-family: var(--font-mono); font-size: 10.5px; letter-spacing: 0.06em; text-transform: uppercase; color: var(--gray-700); margin-bottom: 4px; }
.exam-specs .spec .v { font-family: var(--font-mono); font-size: 17px; font-weight: 600; color: var(--gray-1000); font-variant-numeric: tabular-nums; }
.exam-domains { margin: 0 0 24px; }
.exam-domains .dom-row { display: flex; align-items: center; gap: 12px; padding: 9px 2px; border-bottom: 1px solid var(--gray-a100); font-size: 13px; color: var(--gray-900); }
.exam-domains .dom-row:last-child { border-bottom: none; }
.exam-domains .dom-row .w { margin-left: auto; font-family: var(--font-mono); font-size: 11.5px; color: var(--gray-700); font-variant-numeric: tabular-nums; }
.exam-rules { margin: 0 0 26px; padding: 0; list-style: none; }
.exam-rules li { position: relative; padding: 3px 0 3px 18px; font-size: 13px; color: var(--gray-800); }
.exam-rules li::before { content: "—"; position: absolute; left: 0; color: var(--gray-600); }

/* exam header strip */
.exam-strip {
  display: flex; align-items: center; gap: 14px;
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--gray-700);
}
.exam-strip .mode-flag { color: var(--gray-1000); border: 1px solid var(--gray-a300); border-radius: 4px; padding: 1px 8px; font-size: 10.5px; letter-spacing: 0.05em; }
.exam-strip .spacer { flex: 1; }
.exam-strip .timer { font-size: 14px; font-weight: 600; color: var(--gray-1000); font-variant-numeric: tabular-nums; }
.exam-strip .timer.low { color: var(--red); }
.exam-strip .answered { font-variant-numeric: tabular-nums; }

/* navigator grid */
.exam-nav {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(30px, 1fr));
  gap: 5px;
  margin: 16px 0 0;
  padding: 14px;
  background: var(--bg-100);
  border: 1px solid var(--gray-a200);
  border-radius: var(--radius-md);
}
.exam-nav .cell {
  height: 28px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--gray-a200);
  background: transparent;
  font-family: var(--font-mono);
  font-size: 10.5px;
  color: var(--gray-700);
  font-variant-numeric: tabular-nums;
  transition: background-color 100ms ease, border-color 100ms ease, color 100ms ease;
  position: relative;
}
.exam-nav .cell:hover { border-color: var(--gray-a500); }
.exam-nav .cell.done { background: var(--gray-1000); border-color: var(--gray-1000); color: var(--fg-inverse); }
.exam-nav .cell.cur { border-color: var(--gray-1000); border-width: 2px; }
.exam-nav .cell.flag::after {
  content: ""; position: absolute; top: 3px; right: 3px;
  width: 5px; height: 5px; border-radius: 50%;
  background: var(--red);
}
.flag-btn { color: var(--gray-600); }
.flag-btn.on { color: var(--red); }

/* results */
.result-hero {
  background: var(--bg-100);
  border: 1px solid var(--gray-a200);
  border-radius: var(--radius-lg);
  padding: 36px 32px;
  text-align: center;
  margin-bottom: 16px;
}
.result-hero .verdict-flag {
  display: inline-flex; align-items: center;
  height: 22px; padding: 0 10px;
  border-radius: 5px;
  font-family: var(--font-mono); font-size: 11px; font-weight: 600; letter-spacing: 0.08em;
}
.result-hero .verdict-flag.pass { border: 1px solid var(--green); color: var(--green); background: var(--green-tint); }
.result-hero .verdict-flag.fail { border: 1px solid var(--red); color: var(--red); background: var(--red-tint); }
.result-hero .score {
  font-family: var(--font-mono);
  font-size: 64px; font-weight: 600; letter-spacing: -0.03em; line-height: 1.05;
  color: var(--gray-1000);
  margin: 14px 0 2px;
  font-variant-numeric: tabular-nums;
}
.result-hero .score-cap { font-family: var(--font-mono); font-size: 11.5px; color: var(--gray-600); }
.result-hero .score-meta { margin-top: 14px; font-family: var(--font-mono); font-size: 12px; color: var(--gray-700); font-variant-numeric: tabular-nums; }

.result-card {
  background: var(--bg-100);
  border: 1px solid var(--gray-a200);
  border-radius: var(--radius-lg);
  padding: 24px 28px;
  margin-bottom: 16px;
}
.result-card h3 { margin: 0 0 16px; font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.08em; text-transform: uppercase; font-weight: 500; color: var(--gray-700); }
.dom-perf { display: flex; flex-direction: column; gap: 14px; }
.dom-perf .row { }
.dom-perf .head { display: flex; align-items: baseline; gap: 10px; margin-bottom: 6px; font-size: 13px; color: var(--gray-1000); }
.dom-perf .head .frac { margin-left: auto; font-family: var(--font-mono); font-size: 11.5px; color: var(--gray-700); font-variant-numeric: tabular-nums; }
.dom-perf .head .tier { font-family: var(--font-mono); font-size: 10px; letter-spacing: 0.04em; padding: 1px 6px; border-radius: 4px; border: 1px solid var(--gray-a300); color: var(--gray-800); }
.dom-perf .head .tier.weak { border-color: var(--red); color: var(--red); }
.dom-perf .head .tier.ok { border-color: var(--green); color: var(--green); }
.dom-perf .bar { height: 4px; background: var(--gray-a200); border-radius: 2px; overflow: hidden; }
.dom-perf .bar > div { height: 100%; background: var(--gray-1000); border-radius: 2px; transition: width 500ms ease-out; }
.dom-perf .bar > div.weak { background: var(--red); }

.advice { font-size: 13.5px; line-height: 1.7; color: var(--gray-900); }
.advice b { color: var(--gray-1000); font-weight: 600; }
.advice .concepts-missed { margin-top: 10px; display: flex; flex-wrap: wrap; gap: 6px; }

.result-actions { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 20px; }

/* history on home */
.history-list { display: flex; flex-direction: column; }
.history-row {
  display: flex; align-items: center; gap: 14px;
  padding: 11px 2px;
  border-bottom: 1px solid var(--gray-a100);
  font-size: 13px; color: var(--gray-900);
  background: none; border-left: none; border-right: none; border-top: none;
  text-align: left; width: 100%;
  transition: color 120ms ease;
}
.history-row:hover { color: var(--gray-1000); }
.history-row .date { font-family: var(--font-mono); font-size: 11.5px; color: var(--gray-600); font-variant-numeric: tabular-nums; }
.history-row .hscore { font-family: var(--font-mono); font-weight: 600; color: var(--gray-1000); font-variant-numeric: tabular-nums; }
.history-row .hflag { font-family: var(--font-mono); font-size: 10px; letter-spacing: 0.06em; padding: 1px 6px; border-radius: 4px; border: 1px solid var(--gray-a300); }
.history-row .hflag.pass { border-color: var(--green); color: var(--green); }
.history-row .hflag.fail { border-color: var(--red); color: var(--red); }
.history-row .spacer { flex: 1; }
.history-row .arrow { color: var(--gray-600); font-family: var(--font-mono); font-size: 11px; }

@media (max-width: 640px) {
  .exam-specs { grid-template-columns: repeat(2, 1fr); }
  .exam-specs .spec:nth-child(3), .exam-specs .spec:nth-child(4) { border-top: 1px solid var(--gray-a100); }
  .exam-specs .spec:nth-child(3) { border-left: none; }
  .result-hero .score { font-size: 48px; }
  .exam-nav { grid-template-columns: repeat(auto-fill, minmax(34px, 1fr)); }
}

/* ---------- Activation ---------- */
.activate-card { max-width: 480px; margin: 48px auto 0; }
.activate-card .kicker {
  font-family: var(--font-mono);
  font-size: 11px; letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--gray-700); margin-bottom: 10px;
}
.activate-row { display: flex; gap: 10px; margin-top: 4px; }
.code-input {
  flex: 1; height: 40px;
  padding: 0 14px;
  border: 1px solid var(--gray-a300);
  border-radius: var(--radius-md);
  background: var(--bg-200);
  color: var(--gray-1000);
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.code-input:focus { outline: none; border-color: var(--gray-1000); }
.code-input::placeholder { color: var(--gray-600); text-transform: none; letter-spacing: 0.04em; }
.activate-row .btn { height: 40px; padding: 0 22px; }
.activate-msg { margin-top: 12px; font-size: 12.5px; color: var(--gray-700); min-height: 18px; }
.activate-msg.err { color: var(--red); }