:root {
  --bg: #050908;
  --panel: #0b1514;
  --panel2: #10201e;
  --ink: #edf8f5;
  --muted: #94aaa5;
  --teal: #48dcc6;
  --teal2: #1d8479;
  --gold: #ffc85c;
  --coral: #ff806b;
  --line: #203735;
  --shadow: 0 24px 80px rgba(0, 0, 0, 0.38);
}
* {
  box-sizing: border-box;
}
html {
  scroll-behavior: smooth;
}
body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 8% 4%, rgba(72, 220, 198, 0.12), transparent 25%),
    radial-gradient(
      circle at 90% 60%,
      rgba(255, 200, 92, 0.06),
      transparent 28%
    ),
    var(--bg);
  font-family: "Microsoft YaHei", "PingFang SC", system-ui, sans-serif;
  line-height: 1.7;
}
button,
input {
  font: inherit;
}
button {
  color: inherit;
}
.shell {
  width: min(1180px, calc(100% - 36px));
  margin: auto;
}
.nav {
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid rgba(72, 220, 198, 0.14);
  background: rgba(5, 9, 8, 0.78);
  backdrop-filter: blur(18px);
}
.nav-inner {
  height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 22px;
}
.brand {
  font-weight: 800;
  letter-spacing: 0.04em;
}
.brand i {
  display: inline-block;
  width: 9px;
  height: 9px;
  margin-right: 10px;
  border-radius: 50%;
  background: var(--teal);
  box-shadow: 0 0 18px var(--teal);
}
.nav-links {
  display: flex;
  gap: 26px;
}
.nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 14px;
}
.nav a:hover {
  color: var(--ink);
}
.hero {
  min-height: 620px;
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  align-items: center;
  gap: 72px;
  padding: 88px 0 72px;
}
.eyebrow {
  color: var(--teal);
  font-weight: 700;
  letter-spacing: 0.18em;
  font-size: 13px;
}
.hero h1 {
  font-size: clamp(44px, 6.6vw, 80px);
  line-height: 1.08;
  letter-spacing: -0.045em;
  margin: 18px 0 24px;
  max-width: 770px;
}
.hero h1 span {
  color: var(--teal);
}
.lead {
  font-size: 18px;
  color: var(--muted);
  max-width: 650px;
}
.hero-actions {
  display: flex;
  gap: 12px;
  margin-top: 32px;
}
.btn {
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 11px 20px;
  background: transparent;
  cursor: pointer;
  text-decoration: none;
}
.btn.primary {
  background: var(--teal);
  border-color: var(--teal);
  color: #06201c;
  font-weight: 800;
}
.btn:hover {
  transform: translateY(-1px);
}
.hero-visual {
  position: relative;
  aspect-ratio: 1;
  border-radius: 50%;
  border: 1px solid rgba(72, 220, 198, 0.26);
  display: grid;
  place-items: center;
  background: radial-gradient(
    circle,
    rgba(72, 220, 198, 0.13),
    transparent 62%
  );
}
.orbit {
  position: absolute;
  border: 1px solid rgba(72, 220, 198, 0.18);
  border-radius: 50%;
  animation: spin 20s linear infinite;
}
.orbit.o1 {
  inset: 14%;
}
.orbit.o2 {
  inset: 27%;
  animation-direction: reverse;
  animation-duration: 13s;
}
.planet {
  position: absolute;
  width: 15px;
  height: 15px;
  border-radius: 50%;
  top: -8px;
  left: 50%;
  background: var(--gold);
  box-shadow: 0 0 20px rgba(255, 200, 92, 0.5);
}
.hero-stat {
  text-align: center;
}
.hero-stat strong {
  font-family: Cambria, serif;
  font-size: 58px;
  color: var(--teal);
}
.hero-stat small {
  display: block;
  color: var(--muted);
  letter-spacing: 0.12em;
}
.float-card {
  position: absolute;
  padding: 12px 16px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: rgba(11, 21, 20, 0.88);
  box-shadow: var(--shadow);
  font-size: 13px;
}
.fc1 {
  left: -7%;
  top: 24%;
}
.fc2 {
  right: -8%;
  bottom: 24%;
}
.float-card b {
  color: var(--gold);
}
@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}
.section {
  padding: 78px 0;
}
.section-head {
  display: flex;
  justify-content: space-between;
  align-items: end;
  gap: 32px;
  margin-bottom: 32px;
}
.kicker {
  color: var(--teal);
  font-size: 13px;
  letter-spacing: 0.15em;
  font-weight: 800;
}
.section h2 {
  font-size: clamp(30px, 4vw, 48px);
  line-height: 1.2;
  margin: 7px 0 0;
}
.section-desc {
  color: var(--muted);
  max-width: 490px;
}
.chapter-tabs {
  display: flex;
  gap: 9px;
  overflow: auto;
  padding: 2px 0 18px;
  scrollbar-width: thin;
}
.chapter-tab {
  white-space: nowrap;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--panel);
  padding: 8px 15px;
  cursor: pointer;
  color: var(--muted);
}
.chapter-tab.active {
  color: #071311;
  background: var(--teal);
  border-color: var(--teal);
  font-weight: 800;
}
.chapter-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}
.chapter-card {
  position: relative;
  min-height: 300px;
  padding: 25px 25px 58px;
  border: 1px solid var(--line);
  border-radius: 22px;
  background: linear-gradient(
    145deg,
    rgba(16, 32, 30, 0.92),
    rgba(8, 16, 15, 0.96)
  );
  overflow: hidden;
  transition: 0.25s;
}
.chapter-card:hover {
  transform: translateY(-4px);
  border-color: rgba(72, 220, 198, 0.5);
}
.chapter-card .num {
  font-family: Cambria, serif;
  font-size: 13px;
  color: var(--teal);
}
.chapter-card h3 {
  font-size: 23px;
  line-height: 1.35;
  margin: 25px 0 8px;
}
.chapter-card p {
  color: var(--muted);
  margin: 0;
  font-size: 14px;
}
.chapter-card .count {
  position: absolute;
  bottom: 20px;
  right: 22px;
  color: var(--gold);
  font-size: 13px;
}
.topic-preview {
  display: grid;
  gap: 7px;
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
}
.topic-preview li {
  position: relative;
  padding-left: 15px;
  color: #bfd0cc;
  font-size: 13px;
  line-height: 1.45;
}
.topic-preview li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.65em;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--teal2);
}
.mini-chart {
  position: absolute;
  right: -18px;
  top: -16px;
  width: 120px;
  height: 90px;
  opacity: 0.35;
}
.mini-chart span {
  position: absolute;
  bottom: 0;
  width: 18px;
  border-radius: 5px 5px 0 0;
  background: var(--teal);
}
.method {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 1px;
  border: 1px solid var(--line);
  border-radius: 22px;
  overflow: hidden;
  background: var(--line);
}
.method-item {
  background: var(--panel);
  padding: 25px 18px;
  min-height: 165px;
}
.method-item b {
  display: grid;
  place-items: center;
  width: 35px;
  height: 35px;
  border-radius: 10px;
  background: var(--panel2);
  color: var(--teal);
  margin-bottom: 25px;
}
.method-item strong {
  display: block;
}
.method-item span {
  font-size: 13px;
  color: var(--muted);
}
.faq-list {
  display: grid;
  gap: 12px;
  grid-column: 1/-1;
}
.faq-link {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 22px;
  padding: 21px 23px;
  border: 1px solid var(--line);
  border-radius: 17px;
  background: linear-gradient(145deg, var(--panel2), var(--panel));
  color: var(--ink);
  text-decoration: none;
  transition: 0.2s;
}
.faq-link:hover {
  border-color: rgba(72, 220, 198, 0.6);
  transform: translateY(-2px);
}
.faq-link strong {
  font-size: 17px;
}
.faq-link span {
  color: var(--teal);
  white-space: nowrap;
}
.module-faq {
  margin-top: 18px;
  padding: 22px;
  border: 1px solid rgba(255, 200, 92, 0.24);
  border-radius: 19px;
  background: rgba(255, 200, 92, 0.05);
}
.module-faq-head {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  align-items: center;
  margin-bottom: 12px;
}
.module-faq-head span {
  color: var(--muted);
  font-size: 13px;
}
.module-question {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: 13px;
  background: var(--panel);
  color: var(--ink);
  text-decoration: none;
}
.module-question b {
  color: var(--teal);
  white-space: nowrap;
}
.question-placeholder {
  padding: 14px 16px;
  border: 1px dashed var(--line);
  border-radius: 13px;
  color: var(--muted);
  font-size: 14px;
}
.footer {
  padding: 45px 0 60px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  display: flex;
  justify-content: space-between;
  gap: 30px;
}
.footer strong {
  color: var(--ink);
}
dialog {
  width: min(1120px, calc(100% - 24px));
  max-height: calc(100vh - 24px);
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 26px;
  background: #081110;
  color: var(--ink);
  box-shadow: 0 30px 120px #000;
  overflow: auto;
}
dialog::backdrop {
  background: rgba(0, 0, 0, 0.72);
  backdrop-filter: blur(8px);
}
.lab {
  padding: 28px;
}
.lab-top {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  align-items: start;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--line);
}
.lab-title h2 {
  font-size: clamp(28px, 4vw, 44px);
  margin: 5px 0;
}
.lab-title p {
  margin: 0;
  color: var(--muted);
}
.close {
  width: 42px;
  height: 42px;
  flex: 0 0 auto;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: var(--panel);
  font-size: 22px;
  cursor: pointer;
}
.lab-grid {
  display: grid;
  grid-template-columns: 300px 1fr;
  gap: 22px;
  margin-top: 22px;
}
.stack {
  display: grid;
  gap: 16px;
}
.lab-card {
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--panel);
  padding: 20px;
}
.lab-card h3 {
  font-size: 13px;
  letter-spacing: 0.13em;
  color: var(--teal);
  margin: 0 0 14px;
}
.concept {
  font-size: 15px;
  color: #cbdad6;
}
.concept strong {
  color: var(--gold);
}
.control {
  margin: 15px 0;
}
.control label {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  color: var(--muted);
  font-size: 14px;
}
.control output {
  color: var(--ink);
  font-weight: 800;
}
.control input {
  width: 100%;
  accent-color: var(--teal);
}
.chart-card {
  min-height: 450px;
  display: flex;
  flex-direction: column;
}
.chart-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 14px;
}
.metric {
  font-size: 30px;
  font-weight: 800;
  color: var(--coral);
}
canvas {
  display: block;
  width: 100%;
  height: 320px;
  margin-top: auto;
}
.formula {
  font-family: Cambria, "Times New Roman", serif;
  font-size: clamp(20px, 3vw, 29px);
  color: var(--ink);
  text-align: center;
  padding: 15px 4px;
}
.formula-note {
  color: var(--muted);
  font-size: 13px;
  text-align: center;
}
.exam {
  margin: 0;
  color: #d5e2df;
}
.options {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 8px;
  margin-top: 15px;
}
.option {
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 10px 12px;
  background: #0c1917;
  cursor: pointer;
  text-align: left;
  font-size: 14px;
}
.option:hover {
  border-color: var(--teal);
}
.option.correct {
  border-color: var(--teal);
  background: rgba(72, 220, 198, 0.12);
}
.option.wrong {
  border-color: var(--coral);
  background: rgba(255, 128, 107, 0.1);
}
.answer {
  min-height: 28px;
  color: var(--muted);
  font-size: 13px;
  margin-top: 10px;
}
.next {
  width: 100%;
  margin-top: 4px;
  background: transparent;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 10px;
  cursor: pointer;
}
.empty {
  grid-column: 1/-1;
  text-align: center;
  padding: 80px 20px;
  color: var(--muted);
}
@media (max-width: 900px) {
  .hero {
    grid-template-columns: 1fr;
    min-height: auto;
    padding-top: 70px;
  }
  .hero-visual {
    width: min(500px, 85vw);
    margin: 0 auto;
  }
  .chapter-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .method {
    grid-template-columns: repeat(2, 1fr);
  }
  .lab-grid {
    grid-template-columns: 1fr;
  }
  .chart-card {
    min-height: 390px;
  }
  .nav-links {
    display: none;
  }
}
@media (max-width: 580px) {
  .shell {
    width: min(100% - 22px, 1180px);
  }
  .hero {
    gap: 45px;
  }
  .hero h1 {
    font-size: 42px;
  }
  .float-card {
    display: none;
  }
  .chapter-grid {
    grid-template-columns: 1fr;
  }
  .method {
    grid-template-columns: 1fr;
  }
  .section {
    padding: 55px 0;
  }
  .section-head {
    display: block;
  }
  .lab {
    padding: 18px;
  }
  .options {
    grid-template-columns: 1fr;
  }
  .footer {
    display: block;
  }
  .footer span {
    display: block;
    margin-top: 12px;
  }
}
@media (prefers-reduced-motion: reduce) {
  * {
    scroll-behavior: auto !important;
  }
  .orbit {
    animation: none;
  }
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
}
.brand img {
  display: block;
  width: 34px;
  height: 34px;
  max-width: 34px;
  max-height: 34px;
  object-fit: cover;
  border-radius: 9px;
  border: 1px solid rgba(72, 220, 198, 0.28);
  flex: none;
}
.chapter-card.is-ready {
  cursor: pointer;
}
.chapter-card.is-ready::after {
  content: "查看汇总页";
  position: absolute;
  left: 25px;
  bottom: 19px;
  color: var(--teal);
  font-size: 13px;
  font-weight: 700;
}
.chapter-card.is-ready:hover::after {
  transform: translateX(3px);
}
#introDialog {
  width: min(1180px, calc(100% - 24px));
  background: #07100f;
}
.intro-page {
  padding: 34px;
}
.intro-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--line);
}
.intro-back {
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--panel);
  padding: 8px 15px;
  cursor: pointer;
  color: var(--muted);
}
.intro-hero {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 36px;
  align-items: end;
  padding: 54px 0 42px;
}
.intro-hero h2 {
  font-size: clamp(40px, 6vw, 72px);
  line-height: 1.06;
  letter-spacing: -0.04em;
  margin: 10px 0 18px;
}
.intro-hero h2 span {
  color: var(--teal);
}
.intro-hero p {
  max-width: 670px;
  color: var(--muted);
  font-size: 17px;
}
.intro-meta {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
}
.intro-meta div {
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--panel);
}
.intro-meta strong {
  display: block;
  color: var(--gold);
  font-size: 25px;
}
.intro-meta span {
  color: var(--muted);
  font-size: 12px;
}
.roadmap {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 25px;
  color: var(--muted);
  font-size: 13px;
}
.roadmap i {
  height: 1px;
  flex: 1;
  background: linear-gradient(90deg, var(--teal2), var(--line));
}
.intro-topics {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}
.intro-topic {
  position: relative;
  min-height: 230px;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 19px;
  background: linear-gradient(145deg, var(--panel2), var(--panel));
  transition: 0.2s;
}
.intro-topic.clickable {
  cursor: pointer;
}
.intro-topic.clickable:hover {
  transform: translateY(-3px);
  border-color: rgba(72, 220, 198, 0.65);
  box-shadow: 0 18px 44px rgba(0, 0, 0, 0.22);
}
.intro-topic .topic-no {
  font-family: Cambria, serif;
  color: var(--teal);
  font-size: 13px;
}
.intro-topic h3 {
  font-size: 20px;
  line-height: 1.4;
  margin: 24px 0 9px;
}
.intro-topic p {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
}
.topic-status {
  position: absolute;
  left: 22px;
  bottom: 20px;
  color: var(--gold);
  font-size: 12px;
}
.intro-callout {
  display: flex;
  justify-content: space-between;
  gap: 25px;
  align-items: center;
  margin-top: 18px;
  padding: 24px;
  border: 1px solid rgba(72, 220, 198, 0.22);
  border-radius: 19px;
  background: rgba(72, 220, 198, 0.06);
}
.intro-callout strong {
  font-size: 18px;
}
.intro-callout span {
  color: var(--muted);
  font-size: 13px;
}
@media (max-width: 850px) {
  .intro-hero {
    grid-template-columns: 1fr;
  }
  .intro-topics {
    grid-template-columns: repeat(2, 1fr);
  }
}
@media (max-width: 560px) {
  .intro-page {
    padding: 18px;
  }
  .intro-hero {
    padding: 36px 0 28px;
  }
  .intro-topics {
    grid-template-columns: 1fr;
  }
  .intro-callout {
    display: block;
  }
  .intro-callout span {
    display: block;
    margin-top: 8px;
  }
}