:root {
  color-scheme: light dark;
  --paper: #f4f7fb;
  --card: #ffffff;
  --ink: #172033;
  --muted: #657086;
  --line: #d8e0ec;
  --blue: #2457d6;
  --cyan: #0b8fa3;
  --amber: #d98c10;
  --red: #c24845;
  --shadow: 0 22px 70px rgba(31, 48, 82, 0.12);
  --sans: "PingFang SC", "Microsoft YaHei", "Noto Sans CJK SC", system-ui, sans-serif;
  --serif: "Songti SC", "STSong", "Noto Serif CJK SC", Georgia, serif;
  --mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper: #0d121b;
    --card: #161d29;
    --ink: #eef3fb;
    --muted: #9da9bd;
    --line: #2b374b;
    --blue: #82a8ff;
    --cyan: #61c7d4;
    --amber: #f2b74f;
    --red: #ff8a84;
    --shadow: 0 26px 80px rgba(0, 0, 0, 0.32);
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background:
    linear-gradient(90deg, color-mix(in srgb, var(--line) 34%, transparent) 1px, transparent 1px),
    linear-gradient(color-mix(in srgb, var(--line) 26%, transparent) 1px, transparent 1px),
    var(--paper);
  background-size: 48px 48px;
  color: var(--ink);
  font-family: var(--sans);
  line-height: 1.65;
}
a { color: inherit; }
button, input { font: inherit; }
.shell { width: min(100% - 40px, 920px); margin: 0 auto; padding: 24px 0 80px; }
.topbar { display: flex; align-items: center; justify-content: space-between; gap: 20px; font-family: var(--mono); font-size: 0.76rem; letter-spacing: 0.08em; text-transform: uppercase; }
.back-link { text-decoration: none; }
.back-link:hover { color: var(--blue); }
.privacy { color: var(--cyan); }
.hero { padding: clamp(64px, 10vw, 112px) 0 52px; border-bottom: 1px solid var(--line); }
.eyebrow, .progress-label, .result-code, .next-move > span { font-family: var(--mono); font-size: 0.74rem; font-weight: 700; letter-spacing: 0.12em; }
.eyebrow { margin: 0 0 22px; color: var(--cyan); }
.hero h1 { max-width: 760px; margin: 0; font-family: var(--serif); font-size: clamp(2.7rem, 8vw, 5.6rem); line-height: 1.04; letter-spacing: -0.05em; }
.hero h1 em { color: var(--blue); font-style: normal; }
.hero-copy { max-width: 650px; margin: 26px 0 0; color: var(--muted); font-size: 1.02rem; }
.status-console { display: grid; grid-template-columns: 1fr auto; gap: 22px; margin-top: 34px; padding: 18px 20px; border: 1px solid var(--line); border-left: 4px solid var(--amber); background: var(--card); box-shadow: var(--shadow); }
.status-console strong { display: block; font-family: var(--mono); font-size: 0.82rem; letter-spacing: 0.06em; }
.status-console span { color: var(--muted); font-size: 0.88rem; }
.status-console .blink { align-self: center; color: var(--amber); }
.progress-sticky { position: sticky; z-index: 10; top: 0; display: grid; grid-template-columns: auto 1fr auto; align-items: center; gap: 16px; padding: 15px 2px; background: color-mix(in srgb, var(--paper) 91%, transparent); backdrop-filter: blur(12px); }
.progress-label { color: var(--muted); }
.progress-track, .signal-track { overflow: hidden; height: 7px; background: var(--line); }
.progress-track span, .signal-track span { display: block; width: 0; height: 100%; background: var(--blue); transition: width 240ms ease; }
#progress-text { font-family: var(--mono); font-size: 0.82rem; }
.questions { display: grid; gap: 16px; padding-top: 20px; }
.question { margin: 0; padding: clamp(20px, 4vw, 30px); border: 1px solid var(--line); background: var(--card); }
.question:focus-within { border-color: var(--blue); }
.question legend { display: flex; gap: 14px; width: 100%; padding: 0; color: var(--ink); font-family: var(--serif); font-size: clamp(1.05rem, 3vw, 1.22rem); font-weight: 700; line-height: 1.55; }
.question legend span { flex: 0 0 auto; color: var(--cyan); font-family: var(--mono); font-size: 0.75rem; line-height: 2.05rem; }
.choices { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 8px; margin-top: 22px; }
.choice { position: relative; cursor: pointer; text-align: center; }
.choice input { position: absolute; opacity: 0; pointer-events: none; }
.choice > span:last-child { display: block; margin-top: 7px; color: var(--muted); font-size: 0.75rem; }
.choice-dot { display: grid; width: 42px; height: 42px; margin: 0 auto; place-items: center; border: 1px solid var(--line); color: var(--muted); font-family: var(--mono); transition: border-color 140ms ease, background 140ms ease, color 140ms ease, transform 140ms ease; }
.choice:hover .choice-dot { border-color: var(--blue); transform: translateY(-2px); }
.choice input:checked + .choice-dot { border-color: var(--blue); background: var(--blue); color: #fff; }
.choice input:focus-visible + .choice-dot { outline: 3px solid color-mix(in srgb, var(--blue) 48%, transparent); outline-offset: 3px; }
.form-actions { display: flex; align-items: center; justify-content: space-between; gap: 20px; margin-top: 24px; }
.button { min-height: 46px; padding: 0 20px; border: 1px solid var(--blue); background: var(--blue); color: #fff; cursor: pointer; font-weight: 700; }
.button.secondary { border-color: var(--line); background: transparent; color: var(--ink); }
.button:hover { filter: brightness(1.08); }
.button:focus-visible, .back-link:focus-visible { outline: 3px solid color-mix(in srgb, var(--blue) 50%, transparent); outline-offset: 3px; }
.form-error { margin: 0; color: var(--red); font-weight: 650; }
.result { margin-top: 52px; padding: clamp(24px, 6vw, 48px); border: 1px solid var(--line); border-top: 6px solid var(--cyan); background: var(--card); box-shadow: var(--shadow); outline: none; }
.result[data-level="watch"] { border-top-color: var(--amber); }
.result[data-level="reduce"], .result[data-level="pause"] { border-top-color: var(--red); }
.result-code { display: flex; justify-content: space-between; color: var(--muted); }
.result-code strong { color: var(--cyan); }
.result[data-level="watch"] .result-code strong { color: var(--amber); }
.result[data-level="reduce"] .result-code strong, .result[data-level="pause"] .result-code strong { color: var(--red); }
.result-score { display: flex; align-items: baseline; gap: 10px; margin: 30px 0 4px; }
.result-score span { font-family: var(--mono); font-size: clamp(4.4rem, 14vw, 8rem); font-weight: 800; line-height: 0.9; letter-spacing: -0.08em; }
.result-score small { color: var(--muted); }
.result h2 { margin: 24px 0 8px; font-family: var(--serif); font-size: clamp(1.8rem, 5vw, 2.7rem); }
.result-summary { max-width: 660px; margin: 0; color: var(--muted); }
.signal-list { display: grid; grid-template-columns: 1fr 1fr; gap: 20px 28px; margin-top: 34px; }
.signal-row > div:first-child { display: flex; justify-content: space-between; margin-bottom: 7px; font-size: 0.88rem; }
.signal-row strong { font-family: var(--mono); }
.signal-row small { color: var(--muted); font-weight: 400; }
.signal-track span { background: var(--cyan); }
.next-move { margin-top: 36px; padding: 20px; border-left: 4px solid var(--blue); background: color-mix(in srgb, var(--blue) 8%, var(--card)); }
.next-move > span { color: var(--blue); }
.next-move p { margin: 8px 0 0; }
.result-note { margin: 28px 0 0; padding-top: 18px; border-top: 1px solid var(--line); color: var(--muted); font-size: 0.8rem; }
.reset-actions { margin-top: 16px; }
.page-footer { margin-top: 50px; color: var(--muted); font-family: var(--mono); font-size: 0.74rem; text-align: center; }
[hidden] { display: none !important; }

@media (max-width: 640px) {
  .shell { width: min(100% - 28px, 920px); padding-top: 18px; }
  .topbar { align-items: flex-start; }
  .privacy { max-width: 150px; text-align: right; }
  .hero { padding-top: 58px; }
  .status-console { grid-template-columns: 1fr; }
  .status-console .blink { display: none; }
  .progress-sticky { gap: 10px; }
  .choices { grid-template-columns: repeat(5, minmax(46px, 1fr)); overflow-x: auto; padding: 4px 0 8px; }
  .choice > span:last-child { font-size: 0.68rem; line-height: 1.25; }
  .form-actions { align-items: flex-start; flex-direction: column; }
  .form-actions .button { width: 100%; }
  .signal-list { grid-template-columns: 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { scroll-behavior: auto !important; transition: none !important; }
}