:root {
  --ink: #17302d;
  --muted: #60716e;
  --paper: #f4f3ed;
  --white: #fff;
  --line: #d7ddd6;
  --forest: #103f3b;
  --forest-deep: #092e2b;
  --mint: #dbe9df;
  --mint-bright: #b9dac9;
  --gold: #a76d2a;
  --coral: #dd765a;
  --shadow: 0 28px 70px rgba(17, 58, 53, 0.14);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: radial-gradient(circle at 88% 2%, rgba(182, 216, 200, 0.42), transparent 25rem), var(--paper);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
a:focus-visible { outline: 3px solid #d18d35; outline-offset: 4px; }
h1, h2, h3, p { margin-top: 0; }
h1, h2 {
  font-family: Georgia, "Times New Roman", "Songti SC", serif;
  font-weight: 500;
  letter-spacing: -0.04em;
}

.skip-link {
  position: fixed;
  top: 1rem;
  left: 1rem;
  z-index: 100;
  padding: 0.55rem 0.85rem;
  color: var(--white);
  background: var(--forest);
  transform: translateY(-180%);
}
.skip-link:focus { transform: translateY(0); }

.site-header, .hero, .signal-strip, .section, .boundary, .site-footer {
  width: min(1160px, calc(100% - 3rem));
  margin: 0 auto;
}
.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
  min-height: 92px;
}
.brand { display: inline-flex; align-items: center; gap: 0.75rem; }
.brand-mark {
  display: grid;
  width: 44px;
  height: 44px;
  place-items: center;
  color: var(--white);
  background: var(--forest);
  border-radius: 50% 50% 50% 9px;
  box-shadow: 0 9px 20px rgba(16, 63, 59, 0.18);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 0.9rem;
  letter-spacing: 0.06em;
}
.brand strong, .brand small { display: block; line-height: 1.15; }
.brand strong { font-size: 1.05rem; font-weight: 650; }
.brand small {
  margin-top: 0.18rem;
  color: var(--muted);
  font-family: Georgia, serif;
  font-size: 0.78rem;
  letter-spacing: 0.08em;
}
nav { display: flex; gap: 1.45rem; color: var(--muted); font-size: 0.9rem; }
nav a { position: relative; padding: 0.4rem 0; }
nav a::after {
  position: absolute;
  right: 0;
  bottom: 0;
  left: 0;
  height: 1px;
  background: var(--forest);
  content: "";
  transform: scaleX(0);
  transform-origin: right;
  transition: transform 180ms ease;
}
nav a:hover { color: var(--forest); }
nav a:hover::after { transform: scaleX(1); transform-origin: left; }

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.03fr) minmax(390px, 0.82fr);
  gap: clamp(3rem, 7vw, 7.5rem);
  align-items: center;
  min-height: 680px;
  padding: clamp(4.5rem, 8vw, 7.4rem) 0 clamp(5rem, 9vw, 7.6rem);
}
.eyebrow, .section-kicker, .card-label {
  margin: 0 0 0.85rem;
  color: var(--gold);
  font-size: 0.73rem;
  font-weight: 750;
  letter-spacing: 0.15em;
}
h1 {
  max-width: 760px;
  margin-bottom: 1.4rem;
  font-size: clamp(2.8rem, 5.4vw, 5rem);
  line-height: 1.1;
}
h2 { margin-bottom: 0; font-size: clamp(1.9rem, 3.2vw, 2.9rem); line-height: 1.23; }
.hero-lead { max-width: 680px; margin-bottom: 2rem; color: var(--muted); font-size: 1.06rem; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 0.8rem; }
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 1.3rem;
  min-height: 48px;
  padding: 0.72rem 1.15rem;
  border: 1px solid transparent;
  font-size: 0.92rem;
  transition: transform 180ms ease, background 180ms ease, border-color 180ms ease;
}
.button:hover { transform: translateY(-2px); }
.button-primary { color: var(--white); background: var(--forest); }
.button-primary:hover { background: #185650; }
.button-quiet { border-color: var(--line); background: rgba(255, 255, 255, 0.58); }
.button-quiet:hover { border-color: var(--forest); }
.hero-points {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem 1.15rem;
  margin: 1.65rem 0 0;
  padding: 0;
  color: var(--muted);
  list-style: none;
  font-size: 0.8rem;
}
.hero-points li::before {
  display: inline-block;
  width: 5px;
  height: 5px;
  margin: 0 0.5rem 0.1rem 0;
  background: var(--coral);
  border-radius: 50%;
  content: "";
}

.product-preview { position: relative; justify-self: end; width: min(100%, 430px); }
.preview-glow {
  position: absolute;
  inset: 7% -9% -7% 11%;
  background: var(--mint-bright);
  border-radius: 42% 58% 49% 51% / 58% 39% 61% 42%;
  opacity: 0.75;
  transform: rotate(-6deg);
}
.preview-window {
  position: relative;
  overflow: hidden;
  min-height: 480px;
  padding: 1.1rem;
  background: rgba(255, 255, 255, 0.94);
  border: 1px solid rgba(16, 63, 59, 0.16);
  border-radius: 28px;
  box-shadow: var(--shadow);
  transform: rotate(1.5deg);
}
.preview-topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.2rem 0.35rem 1rem;
  color: var(--forest);
  font-size: 0.83rem;
}
.preview-title { font-weight: 700; }
.preview-dots { letter-spacing: 0.12em; }
.search-box {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  min-height: 53px;
  padding: 0 1rem;
  color: var(--forest);
  background: #f1f5f1;
  border: 1px solid #d9e3dc;
  border-radius: 12px;
}
.search-box > span:first-child { font-size: 1.35rem; line-height: 1; }
.search-box strong { font-size: 0.95rem; }
.search-hint { margin-left: auto; color: #8b9996; font-size: 0.69rem; }
.result-card {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 1rem;
  align-items: center;
  margin-top: 1rem;
  padding: 1.15rem;
}
.result-primary {
  color: var(--white);
  background: radial-gradient(circle at 92% 15%, rgba(164, 209, 185, 0.22), transparent 8rem), var(--forest);
  border-radius: 16px;
}
.nuclide-symbol {
  display: grid;
  width: 78px;
  height: 78px;
  place-items: center;
  color: var(--forest);
  background: var(--mint);
  border-radius: 16px;
}
.nuclide-symbol small, .nuclide-symbol strong { grid-area: 1 / 1; }
.nuclide-symbol small {
  align-self: start;
  justify-self: start;
  margin: 0.55rem;
  font-family: Georgia, serif;
  font-size: 0.7rem;
}
.nuclide-symbol strong { font-family: Georgia, serif; font-size: 2rem; }
.result-type { margin-bottom: 0.05rem; color: #afd0be; font-size: 0.67rem; letter-spacing: 0.08em; }
.result-card h2 { margin: 0 0 0.15rem; font-family: inherit; font-size: 1.1rem; font-weight: 700; letter-spacing: 0; }
.result-card p:last-child { margin: 0; color: rgba(255, 255, 255, 0.7); font-size: 0.72rem; line-height: 1.55; }
.result-arrow { font-size: 1.25rem; }
.result-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 0.8rem; margin-top: 0.8rem; }
.mini-result {
  display: grid;
  min-height: 116px;
  padding: 0.9rem;
  background: var(--paper);
  border-radius: 14px;
}
.mini-icon { color: var(--gold); font-size: 1.4rem; }
.mini-result strong, .mini-result small { align-self: end; }
.mini-result strong { font-size: 0.83rem; }
.mini-result small { color: var(--muted); font-size: 0.68rem; }
.preview-caption {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.55rem;
  margin-top: 1.15rem;
  color: var(--muted);
  font-size: 0.73rem;
}
.live-dot { width: 7px; height: 7px; background: #48a076; border-radius: 50%; box-shadow: 0 0 0 5px rgba(72, 160, 118, 0.12); }

.signal-strip { display: grid; grid-template-columns: repeat(4, 1fr); margin-bottom: 1rem; color: var(--white); background: var(--forest); }
.signal-strip > div {
  display: flex;
  align-items: baseline;
  gap: 0.8rem;
  padding: 1.25rem 1.4rem;
  border-right: 1px solid rgba(255, 255, 255, 0.16);
}
.signal-strip > div:last-child { border-right: 0; }
.signal-strip strong { color: #b9dec9; font-family: Georgia, "Songti SC", serif; font-size: 1.55rem; }
.signal-strip span { color: rgba(255, 255, 255, 0.73); font-size: 0.78rem; }

.section { padding: clamp(4.3rem, 8vw, 7rem) 0; border-top: 1px solid var(--line); }
.intro { display: grid; grid-template-columns: 0.9fr 1.1fr; gap: clamp(2rem, 8vw, 7rem); }
.intro-copy { max-width: 620px; color: var(--muted); font-size: 1.03rem; }
.intro-copy p:last-child { margin-bottom: 0; }
.section-heading { display: flex; align-items: end; justify-content: space-between; gap: 2rem; margin-bottom: 2.2rem; }
.section-heading > p { max-width: 320px; margin-bottom: 0.3rem; color: var(--muted); font-size: 0.88rem; text-align: right; }

.feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; }
.feature-card {
  position: relative;
  min-height: 330px;
  padding: 1.45rem;
  background: rgba(255, 255, 255, 0.72);
  border: 1px solid var(--line);
  transition: transform 180ms ease, box-shadow 180ms ease;
}
.feature-card:hover { box-shadow: 0 18px 38px rgba(17, 58, 53, 0.08); transform: translateY(-4px); }
.feature-card-large {
  display: grid;
  grid-column: span 2;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 1.5rem;
  color: var(--white);
  background: var(--forest);
  border-color: var(--forest);
}
.feature-card-dark {
  grid-column: span 3;
  min-height: 230px;
  color: var(--white);
  background:
    radial-gradient(circle at 85% 15%, rgba(169, 208, 187, 0.12), transparent 15rem),
    var(--forest-deep);
  border-color: var(--forest-deep);
}
.feature-card-dark h3, .feature-card-dark p { max-width: 680px; }
.card-number { position: absolute; top: 1rem; right: 1.15rem; color: var(--gold); font-family: Georgia, serif; font-size: 0.78rem; }
.feature-card-large .card-number, .feature-card-dark .card-number { color: #a8c9b8; }
.feature-card h3 { margin: 0 0 0.65rem; font-size: 1.22rem; font-weight: 650; line-height: 1.4; }
.feature-card p:last-child { margin-bottom: 0; color: var(--muted); font-size: 0.88rem; }
.feature-card-large p:last-child, .feature-card-dark p:last-child { color: rgba(255, 255, 255, 0.67); }
.feature-card-large > div:last-child { align-self: end; padding-bottom: 0.2rem; }
.feature-visual { align-self: center; }
.search-visual { display: flex; flex-wrap: wrap; gap: 0.55rem; max-width: 280px; }
.search-visual span {
  padding: 0.55rem 0.75rem;
  color: #d8ebdf;
  background: rgba(255, 255, 255, 0.09);
  border: 1px solid rgba(255, 255, 255, 0.13);
  border-radius: 999px;
  font-family: Georgia, serif;
  font-size: 0.84rem;
}
.search-visual span:nth-child(2) { transform: translateY(0.65rem); }
.search-visual span:nth-child(3) { margin-left: 1.8rem; }
.card-icon {
  display: grid;
  width: 70px;
  height: 70px;
  margin: 1.9rem 0 3.1rem;
  place-items: center;
  color: var(--forest);
  background: var(--mint);
  border-radius: 50%;
  font-family: Georgia, serif;
  font-size: 0.9rem;
}
.spectrum-icon { display: flex; align-items: end; justify-content: center; gap: 3px; padding-bottom: 19px; }
.spectrum-icon i { display: block; width: 3px; background: var(--forest); }
.spectrum-icon i:nth-child(1) { height: 9px; }
.spectrum-icon i:nth-child(2) { height: 22px; }
.spectrum-icon i:nth-child(3) { height: 13px; }
.spectrum-icon i:nth-child(4) { height: 30px; }
.spectrum-icon i:nth-child(5) { height: 17px; }
.orbit-icon { position: relative; border: 1px solid var(--mint-bright); background: transparent; }
.orbit-icon::before, .orbit-icon::after {
  position: absolute;
  width: 50px;
  height: 19px;
  border: 1px solid var(--forest);
  border-radius: 50%;
  content: "";
}
.orbit-icon::after { transform: rotate(60deg); }
.orbit-icon i { width: 8px; height: 8px; background: var(--coral); border-radius: 50%; }
.imaging-icon {
  position: relative;
  background: radial-gradient(circle, var(--coral) 0 5px, transparent 6px),
    linear-gradient(135deg, transparent 48%, rgba(16, 63, 59, 0.24) 49% 51%, transparent 52%), var(--mint);
}
.imaging-icon i { position: absolute; inset: 13px; border: 1px solid rgba(16, 63, 59, 0.35); border-radius: 50%; }
.route-line { display: flex; align-items: center; margin: 2.25rem 0 3.45rem; }
.route-line i { position: relative; width: 34px; height: 1px; background: rgba(255, 255, 255, 0.28); }
.route-line i::before { position: absolute; top: -4px; left: 0; width: 9px; height: 9px; background: #a9d0bb; border-radius: 50%; content: ""; }
.route-line i:last-child { width: 9px; }

.labs { display: grid; grid-template-columns: 0.8fr 1.2fr; gap: clamp(3rem, 8vw, 7rem); }
.labs-intro { align-self: start; position: sticky; top: 2rem; }
.labs-intro > p:last-child { max-width: 430px; margin-top: 1.25rem; color: var(--muted); }
.lab-list article {
  display: grid;
  grid-template-columns: 42px 1fr auto;
  gap: 1rem;
  align-items: center;
  min-height: 126px;
  padding: 1.2rem 0;
  border-top: 1px solid var(--line);
}
.lab-list article:last-child { border-bottom: 1px solid var(--line); }
.lab-list article > span { color: var(--gold); font-family: Georgia, serif; font-size: 0.82rem; }
.lab-list h3 { margin: 0 0 0.15rem; font-size: 1.08rem; font-weight: 650; }
.lab-list p { margin: 0; color: var(--muted); font-size: 0.83rem; }
.lab-list small { padding: 0.28rem 0.55rem; color: var(--forest); background: var(--mint); border-radius: 999px; white-space: nowrap; font-size: 0.68rem; }

.journey-steps { display: grid; grid-template-columns: repeat(3, 1fr); margin: 0; padding: 0; list-style: none; }
.journey-steps li { position: relative; min-height: 260px; padding: 1.5rem 2rem 1.4rem 0; border-top: 1px solid var(--forest); }
.journey-steps li:not(:last-child)::after {
  position: absolute;
  top: -4px;
  right: 1rem;
  width: 7px;
  height: 7px;
  background: var(--forest);
  border-radius: 50%;
  content: "";
}
.journey-steps li > span { display: block; margin-bottom: 3.5rem; color: var(--gold); font-family: Georgia, serif; font-size: 0.82rem; }
.step-label { margin-bottom: 0.25rem; color: var(--gold); font-size: 0.67rem; letter-spacing: 0.12em; }
.journey-steps h3 { margin-bottom: 0.55rem; font-size: 1.18rem; }
.journey-steps p:last-child { max-width: 290px; margin-bottom: 0; color: var(--muted); font-size: 0.85rem; }

.start {
  position: relative;
  display: grid;
  overflow: hidden;
  grid-template-columns: auto 1fr auto;
  gap: 2rem;
  align-items: center;
  padding-right: clamp(1.7rem, 5vw, 4rem);
  padding-left: clamp(1.7rem, 5vw, 4rem);
  color: var(--white);
  background: radial-gradient(circle at 18% 20%, rgba(196, 228, 211, 0.19), transparent 15rem), var(--forest);
  border-top: 0;
}
.start-mark { position: relative; display: grid; width: 120px; height: 120px; place-items: center; }
.start-mark span { z-index: 1; font-family: Georgia, serif; font-size: 2.6rem; }
.start-mark i {
  position: absolute;
  width: 112px;
  height: 42px;
  border: 1px solid rgba(185, 222, 201, 0.65);
  border-radius: 50%;
  transform: rotate(30deg);
}
.start-mark i:last-child { transform: rotate(-30deg); }
.start .section-kicker { color: #b9dec9; }
.start h2 { max-width: 620px; }
.start-copy > p:last-child { margin: 0.7rem 0 0; color: rgba(255, 255, 255, 0.68); }
.wechat-tip { min-width: 190px; padding: 1rem 1.1rem; background: rgba(255, 255, 255, 0.08); border: 1px solid rgba(255, 255, 255, 0.16); }
.wechat-tip small, .wechat-tip strong, .wechat-tip span { display: block; }
.wechat-tip small { color: #a9cbb9; font-size: 0.68rem; }
.wechat-tip strong { margin: 0.15rem 0; font-family: Georgia, serif; font-size: 1.35rem; }
.wechat-tip span { color: rgba(255, 255, 255, 0.65); font-size: 0.7rem; }

.boundary { display: grid; grid-template-columns: auto 1fr; gap: 2rem; padding: 2rem 0; color: var(--muted); border-bottom: 1px solid var(--line); }
.boundary h2 { margin: 0; color: var(--ink); font-family: inherit; font-size: 0.82rem; font-weight: 700; letter-spacing: 0; }
.boundary p { max-width: 850px; margin: 0; font-size: 0.78rem; }
.site-footer { display: flex; justify-content: space-between; gap: 1.5rem; padding: 2rem 0 2.8rem; color: var(--muted); font-size: 0.8rem; }
.site-footer strong { margin-right: 0.6rem; color: var(--ink); font-size: 0.9rem; }
.footer-meta { display: flex; flex-wrap: wrap; justify-content: end; gap: 0.85rem 1.1rem; }
.footer-meta a:hover { color: var(--forest); }

.js .reveal { opacity: 0; transform: translateY(18px); transition: opacity 560ms ease, transform 560ms ease; }
.js .reveal.is-visible { opacity: 1; transform: translateY(0); }

.try-section {
  border-top: 0;
}

.try-heading {
  margin-bottom: 2.5rem;
}

.experiment-shell {
  overflow: hidden;
  background: var(--forest-deep);
  border: 1px solid rgba(16, 63, 59, 0.18);
  border-radius: 3px;
  box-shadow: 0 28px 70px rgba(17, 58, 53, 0.12);
}

.experiment-tabs {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  padding: 0 1.3rem;
  background: #0c3532;
  border-bottom: 1px solid rgba(255, 255, 255, 0.12);
}

.experiment-tab {
  display: flex;
  gap: 0.8rem;
  align-items: center;
  min-height: 66px;
  padding: 0 1rem;
  color: rgba(255, 255, 255, 0.56);
  background: transparent;
  border: 0;
  border-bottom: 2px solid transparent;
  cursor: pointer;
  font: inherit;
  font-size: 0.9rem;
  text-align: left;
}

.experiment-tab span {
  color: #8eb5a2;
  font-family: Georgia, serif;
  font-size: 0.72rem;
}

.experiment-tab:hover {
  color: var(--white);
}

.experiment-tab.is-active {
  color: var(--white);
  border-bottom-color: var(--coral);
}

.experiment-tab:focus-visible,
.nuclide-option:focus-visible,
.quiz-option:focus-visible,
.next-question:focus-visible {
  outline: 3px solid #e8a353;
  outline-offset: -3px;
}

.experiment-panel {
  display: grid;
  grid-template-columns: minmax(0, 0.86fr) minmax(0, 1.14fr);
  min-height: 630px;
}

.experiment-panel[hidden] {
  display: none;
}

.experiment-control,
.experiment-result {
  padding: clamp(2rem, 4.5vw, 4rem);
}

.experiment-control {
  color: var(--white);
  background:
    radial-gradient(circle at 12% 90%, rgba(169, 208, 187, 0.11), transparent 16rem),
    var(--forest-deep);
}

.experiment-eyebrow {
  margin: 0 0 0.7rem;
  color: #9fc8b3;
  font-size: 0.68rem;
  font-weight: 750;
  letter-spacing: 0.14em;
}

.experiment-control h3 {
  max-width: 470px;
  margin: 0 0 0.65rem;
  font-family: Georgia, "Songti SC", serif;
  font-size: clamp(1.65rem, 3vw, 2.35rem);
  font-weight: 500;
  line-height: 1.3;
}

.experiment-lead {
  max-width: 510px;
  margin-bottom: 2rem;
  color: rgba(255, 255, 255, 0.62);
  font-size: 0.88rem;
}

.nuclide-picker {
  margin: 0 0 2rem;
  padding: 0;
  border: 0;
}

.nuclide-picker legend {
  margin-bottom: 0.7rem;
  color: rgba(255, 255, 255, 0.68);
  font-size: 0.76rem;
}

.nuclide-picker > div {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.nuclide-option {
  min-height: 37px;
  padding: 0.45rem 0.75rem;
  color: rgba(255, 255, 255, 0.7);
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 999px;
  cursor: pointer;
  font: inherit;
  font-size: 0.76rem;
}

.nuclide-option:hover {
  color: var(--white);
  border-color: rgba(255, 255, 255, 0.35);
}

.nuclide-option.is-active {
  color: var(--forest-deep);
  background: #bee0cd;
  border-color: #bee0cd;
  font-weight: 700;
}

.range-control {
  margin-bottom: 1.5rem;
}

.range-heading {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
}

.range-heading label {
  color: rgba(255, 255, 255, 0.72);
  font-size: 0.76rem;
}

.range-heading output {
  color: #bee0cd;
  font-family: Georgia, serif;
  font-size: 1.1rem;
}

.range-control input[type="range"] {
  width: 100%;
  height: 28px;
  margin: 0.6rem 0 0;
  accent-color: var(--coral);
  cursor: pointer;
}

.range-scale {
  display: flex;
  justify-content: space-between;
  color: rgba(255, 255, 255, 0.35);
  font-family: Georgia, serif;
  font-size: 0.63rem;
}

.control-hint {
  margin: 0.45rem 0 0;
  color: rgba(255, 255, 255, 0.38);
  font-size: 0.68rem;
}

.nuclide-fact {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.9rem;
  align-items: center;
  padding: 1rem;
  background: rgba(255, 255, 255, 0.055);
  border: 1px solid rgba(255, 255, 255, 0.09);
}

.fact-symbol {
  display: grid;
  width: 54px;
  height: 54px;
  place-items: center;
  color: var(--forest-deep);
  background: var(--mint);
  border-radius: 12px;
  font-family: Georgia, serif;
  font-size: 1.25rem;
}

.nuclide-fact p {
  margin: 0;
  color: rgba(255, 255, 255, 0.57);
  font-size: 0.68rem;
  line-height: 1.55;
}

.nuclide-fact p:first-child {
  color: var(--white);
  font-size: 0.8rem;
}

.experiment-result {
  position: relative;
  color: var(--ink);
  background:
    radial-gradient(circle at 88% 5%, rgba(185, 218, 201, 0.48), transparent 16rem),
    #edf0e9;
}

.result-summary {
  position: absolute;
  top: clamp(1.8rem, 4vw, 3.5rem);
  right: clamp(1.8rem, 4vw, 3.5rem);
  z-index: 2;
  text-align: right;
}

.result-summary p,
.result-summary strong,
.result-summary span {
  display: block;
}

.result-summary p {
  margin: 0;
  color: var(--muted);
  font-size: 0.7rem;
}

.result-summary strong {
  color: var(--forest);
  font-family: Georgia, serif;
  font-size: clamp(2.3rem, 5vw, 4.2rem);
  font-weight: 500;
  line-height: 1.05;
}

.result-summary span {
  color: var(--muted);
  font-size: 0.72rem;
}

.decay-chart {
  position: relative;
  height: 300px;
  margin-top: 1rem;
}

.decay-chart canvas {
  display: block;
  width: 100%;
  height: 100%;
}

.chart-axis-labels {
  position: absolute;
  inset: 0;
  color: #71807c;
  pointer-events: none;
  font-size: 0.63rem;
}

.chart-axis-labels span:nth-child(1) {
  position: absolute;
  top: 17px;
  left: 0;
}

.chart-axis-labels span:nth-child(2) {
  position: absolute;
  top: 50%;
  left: -1.2rem;
  transform: rotate(-90deg) translateX(-50%);
  transform-origin: left top;
}

.chart-axis-labels span:nth-child(3) {
  position: absolute;
  right: 0;
  bottom: 0;
}

.particle-panel {
  margin-top: 1.3rem;
  padding-top: 1.2rem;
  border-top: 1px solid rgba(16, 63, 59, 0.16);
}

.particle-heading {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 0.8rem;
  color: var(--forest);
  font-size: 0.72rem;
}

.particle-heading small {
  color: var(--muted);
  font-size: 0.62rem;
}

.particle-field {
  display: grid;
  grid-template-columns: repeat(16, 1fr);
  gap: 7px;
}

.particle-dot {
  aspect-ratio: 1;
  background: var(--forest);
  border-radius: 50%;
  opacity: 0.11;
  transform: scale(0.72);
  transition: opacity 180ms ease, transform 180ms ease, background 180ms ease;
}

.particle-dot.is-active {
  background: #2f8c68;
  box-shadow: 0 0 0 3px rgba(47, 140, 104, 0.08);
  opacity: 1;
  transform: scale(1);
}

.formula-strip {
  display: flex;
  gap: 0.8rem;
  align-items: baseline;
  justify-content: center;
  margin-top: 1.35rem;
  padding: 0.85rem 1rem;
  color: var(--muted);
  background: rgba(255, 255, 255, 0.48);
  font-family: Georgia, serif;
  font-size: 0.84rem;
}

.formula-strip strong {
  color: var(--forest);
  font-size: 1rem;
  font-weight: 600;
}

.formula-strip sup {
  margin-left: 0.12rem;
  color: var(--coral);
}

.quiz-count {
  display: inline-flex;
  margin-bottom: 0.65rem;
  padding: 0.28rem 0.55rem;
  color: #a9cbb9;
  background: rgba(255, 255, 255, 0.07);
  border-radius: 999px;
  font-size: 0.66rem;
}

.quiz-peaks {
  margin-bottom: 0.3rem;
  color: #f2b27e;
  font-family: Georgia, serif;
  font-size: 1rem;
}

.experiment-control h4 {
  margin: 0 0 1.1rem;
  font-size: 1.02rem;
  font-weight: 600;
}

.quiz-options {
  display: grid;
  gap: 0.55rem;
}

.quiz-option {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 46px;
  padding: 0.65rem 0.8rem;
  color: rgba(255, 255, 255, 0.78);
  background: rgba(255, 255, 255, 0.055);
  border: 1px solid rgba(255, 255, 255, 0.13);
  cursor: pointer;
  font: inherit;
  font-size: 0.78rem;
  text-align: left;
}

.quiz-option::after {
  color: rgba(255, 255, 255, 0.3);
  content: "○";
}

.quiz-option:hover:not(:disabled) {
  color: var(--white);
  border-color: rgba(255, 255, 255, 0.34);
}

.quiz-option.is-correct {
  color: #d8f0e3;
  background: rgba(78, 158, 117, 0.22);
  border-color: rgba(117, 201, 158, 0.55);
}

.quiz-option.is-correct::after {
  color: #9fe1bd;
  content: "✓";
}

.quiz-option.is-wrong {
  color: #ffd5c8;
  background: rgba(221, 118, 90, 0.16);
  border-color: rgba(221, 118, 90, 0.5);
}

.quiz-option.is-wrong::after {
  color: #ffae99;
  content: "×";
}

.quiz-feedback {
  min-height: 64px;
  margin-top: 0.9rem;
  padding: 0.75rem 0.85rem;
  color: rgba(255, 255, 255, 0.56);
  background: rgba(255, 255, 255, 0.045);
  border-left: 2px solid rgba(159, 200, 179, 0.45);
  font-size: 0.72rem;
}

.quiz-feedback strong {
  color: var(--white);
}

.next-question {
  display: inline-flex;
  gap: 2rem;
  align-items: center;
  justify-content: space-between;
  min-height: 44px;
  margin-top: 0.9rem;
  padding: 0.55rem 0.85rem;
  color: var(--forest-deep);
  background: #bee0cd;
  border: 0;
  cursor: pointer;
  font: inherit;
  font-size: 0.76rem;
}

.next-question:disabled {
  cursor: not-allowed;
  opacity: 0.35;
}

.spectrum-result {
  display: grid;
  align-content: center;
  gap: 1.5rem;
}

.spectrum-display {
  position: relative;
  height: 340px;
  border-bottom: 1px solid rgba(16, 63, 59, 0.35);
  border-left: 1px solid rgba(16, 63, 59, 0.35);
}

.spectrum-display canvas {
  display: block;
  width: 100%;
  height: 100%;
}

.spectrum-axis {
  position: absolute;
  right: 0;
  bottom: -1.5rem;
  left: 0;
  display: flex;
  justify-content: space-between;
  color: var(--muted);
  font-size: 0.62rem;
}

.spectrum-note {
  display: flex;
  gap: 0.8rem;
  align-items: flex-start;
  margin-top: 1rem;
  padding: 0.8rem 0.9rem;
  background: rgba(255, 255, 255, 0.48);
}

.spectrum-note .live-dot {
  flex: 0 0 auto;
  margin-top: 0.45rem;
}

.spectrum-note p {
  margin: 0;
  color: var(--muted);
  font-size: 0.7rem;
}

.spectrum-learning {
  padding-top: 1rem;
  border-top: 1px solid rgba(16, 63, 59, 0.16);
}

.spectrum-learning > p {
  margin-bottom: 0.5rem;
  color: var(--forest);
  font-size: 0.72rem;
  font-weight: 700;
}

.spectrum-learning ul {
  display: grid;
  gap: 0.25rem;
  margin: 0;
  padding-left: 1.2rem;
  color: var(--muted);
  font-size: 0.72rem;
}

.lookup-control {
  display: flex;
  flex-direction: column;
}

.lookup-search-label {
  margin-bottom: 0.55rem;
  color: rgba(255, 255, 255, 0.68);
  font-size: 0.76rem;
}

.lookup-search {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  min-height: 50px;
  padding: 0 0.9rem;
  background: rgba(255, 255, 255, 0.07);
  border: 1px solid rgba(255, 255, 255, 0.15);
}

.lookup-search > span {
  color: #a9cbb9;
  font-size: 1.2rem;
}

.lookup-search input {
  width: 100%;
  color: var(--white);
  background: transparent;
  border: 0;
  outline: 0;
  font: inherit;
  font-size: 0.8rem;
}

.lookup-search input::placeholder {
  color: rgba(255, 255, 255, 0.34);
}

.lookup-search:focus-within {
  border-color: #a9cbb9;
  box-shadow: 0 0 0 2px rgba(169, 203, 185, 0.1);
}

.lookup-count {
  margin: 0.65rem 0 0.5rem;
  color: rgba(255, 255, 255, 0.4);
  font-size: 0.66rem;
}

.lookup-list {
  display: grid;
  gap: 0.4rem;
  max-height: 280px;
  overflow-y: auto;
  padding-right: 0.2rem;
}

.lookup-option {
  display: grid;
  grid-template-columns: 72px 1fr auto;
  gap: 0.65rem;
  align-items: center;
  min-height: 50px;
  padding: 0.55rem 0.7rem;
  color: rgba(255, 255, 255, 0.7);
  background: rgba(255, 255, 255, 0.045);
  border: 1px solid rgba(255, 255, 255, 0.09);
  cursor: pointer;
  font: inherit;
  text-align: left;
}

.lookup-option:hover,
.lookup-option.is-active {
  color: var(--white);
  background: rgba(169, 203, 185, 0.12);
  border-color: rgba(169, 203, 185, 0.34);
}

.lookup-option strong {
  font-family: Georgia, serif;
  font-size: 0.82rem;
}

.lookup-option span {
  font-size: 0.72rem;
}

.lookup-option small {
  color: rgba(255, 255, 255, 0.38);
  font-size: 0.62rem;
}

.lookup-empty {
  padding: 1rem;
  color: rgba(255, 255, 255, 0.5);
  background: rgba(255, 255, 255, 0.045);
  font-size: 0.72rem;
}

.random-nuclide {
  display: inline-flex;
  align-items: center;
  justify-content: space-between;
  min-height: 42px;
  margin-top: 0.8rem;
  padding: 0.5rem 0.75rem;
  color: #b9dec9;
  background: transparent;
  border: 1px solid rgba(185, 222, 201, 0.25);
  cursor: pointer;
  font: inherit;
  font-size: 0.72rem;
}

.random-nuclide:hover {
  color: var(--white);
  border-color: rgba(185, 222, 201, 0.5);
}

.lookup-result {
  display: grid;
  align-content: center;
  gap: 1rem;
}

.lookup-card {
  padding: clamp(1.5rem, 4vw, 2.6rem);
  background: rgba(255, 255, 255, 0.66);
  border: 1px solid rgba(16, 63, 59, 0.14);
  box-shadow: 0 18px 45px rgba(16, 63, 59, 0.08);
}

.lookup-card-top {
  display: flex;
  gap: 1.2rem;
  align-items: center;
  padding-bottom: 1.4rem;
  border-bottom: 1px solid rgba(16, 63, 59, 0.13);
}

.lookup-mark {
  display: grid;
  width: 92px;
  height: 92px;
  flex: 0 0 auto;
  place-items: center;
  color: var(--forest);
  background: var(--mint);
  border-radius: 20px;
}

.lookup-mark small,
.lookup-mark strong {
  grid-area: 1 / 1;
}

.lookup-mark small {
  align-self: start;
  justify-self: start;
  margin: 0.65rem;
  font-family: Georgia, serif;
  font-size: 0.7rem;
}

.lookup-mark strong {
  font-family: Georgia, serif;
  font-size: 2.25rem;
}

.lookup-card-label {
  margin-bottom: 0.1rem;
  color: var(--gold);
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.12em;
}

.lookup-card h3 {
  margin: 0;
  font-family: Georgia, "Songti SC", serif;
  font-size: clamp(1.75rem, 4vw, 2.7rem);
  font-weight: 500;
}

.lookup-card-top > div:last-child > span {
  color: var(--muted);
  font-family: Georgia, serif;
  font-size: 0.85rem;
}

.lookup-details {
  margin: 0;
}

.lookup-details div {
  display: grid;
  grid-template-columns: 92px 1fr;
  gap: 1rem;
  padding: 0.85rem 0;
  border-top: 1px solid rgba(16, 63, 59, 0.1);
  font-size: 0.76rem;
}

.lookup-details div:first-child {
  border-top: 0;
}

.lookup-details dt {
  color: var(--muted);
}

.lookup-details dd {
  color: var(--ink);
  text-align: left;
}

.lookup-point {
  margin-top: 0.5rem;
  padding: 1rem;
  color: var(--white);
  background: var(--forest);
}

.lookup-point span {
  color: #a9cbb9;
  font-size: 0.63rem;
  letter-spacing: 0.08em;
}

.lookup-point p {
  margin: 0.25rem 0 0;
  font-size: 0.77rem;
}

.lookup-more {
  display: flex;
  gap: 0.7rem;
  align-items: flex-start;
  padding: 0.8rem 0.9rem;
  background: rgba(255, 255, 255, 0.45);
}

.lookup-more .live-dot {
  flex: 0 0 auto;
  margin-top: 0.4rem;
}

.lookup-more p {
  margin: 0;
  color: var(--muted);
  font-size: 0.7rem;
}

.experiment-boundary {
  margin: 0.85rem 0 0;
  color: var(--muted);
  font-size: 0.7rem;
  text-align: right;
}

@media (max-width: 900px) {
  .hero { grid-template-columns: 1fr; min-height: auto; }
  .product-preview { justify-self: center; width: min(100%, 510px); }
  .signal-strip { grid-template-columns: repeat(2, 1fr); }
  .signal-strip > div:nth-child(2) { border-right: 0; }
  .signal-strip > div:nth-child(-n + 2) { border-bottom: 1px solid rgba(255, 255, 255, 0.16); }
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .feature-card-dark { grid-column: span 2; }
  .labs { grid-template-columns: 1fr; }
  .labs-intro { position: static; }
  .start { grid-template-columns: auto 1fr; }
  .wechat-tip { grid-column: 2; }
  .experiment-panel { grid-template-columns: 1fr; }
  .experiment-control, .experiment-result { padding: clamp(2rem, 6vw, 3.5rem); }
  .experiment-result { min-height: 590px; }
}

@media (max-width: 680px) {
  .site-header, .hero, .signal-strip, .section, .boundary, .site-footer { width: min(100% - 2rem, 1160px); }
  .site-header { min-height: auto; padding: 1.1rem 0; }
  nav { display: none; }
  .hero { gap: 3.2rem; padding: 3.6rem 0 4.4rem; }
  h1 { font-size: clamp(2.55rem, 12vw, 3.6rem); }
  .product-preview { width: calc(100% - 0.8rem); }
  .preview-glow { right: 0; }
  .preview-window { min-height: 445px; border-radius: 22px; }
  .search-hint { display: none; }
  .result-card { grid-template-columns: auto 1fr; }
  .result-arrow { display: none; }
  .signal-strip { grid-template-columns: 1fr; }
  .signal-strip > div { border-right: 0; border-bottom: 1px solid rgba(255, 255, 255, 0.16); }
  .signal-strip > div:last-child { border-bottom: 0; }
  .intro, .feature-card-large, .journey-steps, .start, .boundary { grid-template-columns: 1fr; }
  .section-heading { display: block; }
  .section-heading > p { margin-top: 0.8rem; text-align: left; }
  .feature-grid { grid-template-columns: 1fr; }
  .feature-card-large { grid-column: auto; }
  .feature-card-dark { grid-column: auto; }
  .feature-card { min-height: 300px; }
  .lab-list article { grid-template-columns: 34px 1fr; }
  .lab-list small { grid-column: 2; justify-self: start; }
  .journey-steps li { min-height: auto; padding-bottom: 2.5rem; }
  .journey-steps li:not(:last-child)::after { display: none; }
  .journey-steps li > span { margin-bottom: 1.8rem; }
  .start-mark { width: 90px; height: 90px; }
  .start-mark i { width: 88px; }
  .wechat-tip { grid-column: auto; }
  .boundary { gap: 0.5rem; }
  .site-footer { flex-direction: column; }
  .footer-meta { justify-content: start; }
  .experiment-tabs { padding: 0 0.5rem; }
  .experiment-tab { min-height: 60px; padding: 0 0.35rem; font-size: 0.7rem; }
  .experiment-control, .experiment-result { padding: 1.5rem 1.2rem; }
  .experiment-result { min-height: 535px; }
  .result-summary { position: static; margin-bottom: 0.7rem; text-align: left; }
  .result-summary strong { font-size: 3.1rem; }
  .decay-chart { height: 235px; }
  .particle-field { grid-template-columns: repeat(12, 1fr); gap: 6px; }
  .particle-heading { display: block; }
  .particle-heading small { display: block; margin-top: 0.15rem; }
  .formula-strip { gap: 0.45rem; padding: 0.7rem 0.5rem; font-size: 0.76rem; }
  .spectrum-display { height: 280px; }
  .lookup-list { max-height: 250px; }
  .lookup-option {
    grid-template-columns: 64px 1fr;
    grid-template-rows: auto auto;
    row-gap: 0.18rem;
    min-height: 62px;
    padding-block: 0.65rem;
  }
  .lookup-option strong {
    grid-row: 1 / 3;
    align-self: center;
  }
  .lookup-option span,
  .lookup-option small { grid-column: 2; }
  .lookup-card-top { align-items: flex-start; }
  .lookup-mark { width: 78px; height: 78px; }
  .lookup-mark strong { font-size: 1.85rem; }
  .lookup-details div { grid-template-columns: 76px 1fr; }
  .experiment-boundary { text-align: left; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}