:root {
  --ink: #16211d;
  --muted: #5a6860;
  --leaf: #2f6f4e;
  --moss: #dfe8d7;
  --clay: #b95b3f;
  --sun: #f2c14e;
  --water: #2d788c;
  --paper: #f7f4ec;
  --white: #ffffff;
  --line: rgba(22, 33, 29, 0.14);
  --shadow: 0 22px 55px rgba(20, 38, 31, 0.14);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: Inter, "Segoe UI", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  line-height: 1.6;
}

img,
video {
  display: block;
  width: 100%;
}

a {
  color: inherit;
  text-decoration: none;
}

.site-header {
  background: #0d1713;
  color: var(--white);
}

.topbar {
  position: fixed;
  z-index: 20;
  top: 0;
  left: 0;
  right: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 68px;
  padding: 14px clamp(18px, 5vw, 64px);
  background: rgba(13, 23, 19, 0.88);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.brand {
  font-weight: 800;
  letter-spacing: 0;
  white-space: nowrap;
  font-size: 1.08rem;
}

.topbar-controls {
  display: flex;
  align-items: center;
  gap: 18px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 28px);
  color: rgba(255, 255, 255, 0.78);
  font-size: 0.95rem;
}

.nav-links a:hover {
  color: var(--white);
}

.language-picker {
  display: flex;
  align-items: center;
  gap: 8px;
  color: rgba(255, 255, 255, 0.78);
  font-size: 0.88rem;
  font-weight: 700;
  white-space: nowrap;
}

.language-picker select {
  max-width: 148px;
  min-height: 36px;
  border: 1px solid rgba(255, 255, 255, 0.24);
  border-radius: 8px;
  padding: 7px 30px 7px 10px;
  background: rgba(255, 255, 255, 0.1);
  color: var(--white);
  font: inherit;
  cursor: pointer;
}

.language-picker option {
  color: var(--ink);
  background: var(--white);
}

.hero {
  min-height: 88vh;
  display: grid;
  align-items: end;
  padding: 120px clamp(20px, 6vw, 84px) 80px;
  background:
    linear-gradient(90deg, rgba(13, 23, 19, 0.84), rgba(13, 23, 19, 0.38) 54%, rgba(13, 23, 19, 0.12)),
    url("assets/ppt/image1.png") center / cover no-repeat;
}

.hero-copy {
  width: min(720px, 100%);
}

.eyebrow,
.section-kicker {
  margin: 0 0 10px;
  color: var(--sun);
  text-transform: uppercase;
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.1em;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 18px;
  font-size: clamp(3.4rem, 10vw, 8rem);
  line-height: 0.9;
  letter-spacing: 0;
}

h2 {
  margin-bottom: 16px;
  font-size: clamp(2rem, 4vw, 3.6rem);
  line-height: 1.05;
  letter-spacing: 0;
}

h3 {
  margin-bottom: 10px;
  font-size: 1.2rem;
  line-height: 1.2;
}

.hero-copy p:not(.eyebrow) {
  max-width: 560px;
  color: rgba(255, 255, 255, 0.84);
  font-size: clamp(1.05rem, 2vw, 1.35rem);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 30px;
}

.primary-btn,
.secondary-btn,
.shuffle-btn,
.slogan-box button {
  border: 0;
  border-radius: 8px;
  padding: 12px 18px;
  font: inherit;
  font-weight: 800;
  cursor: pointer;
}

.primary-btn {
  background: var(--sun);
  color: #20180a;
}

.secondary-btn {
  color: var(--white);
  border: 1px solid rgba(255, 255, 255, 0.34);
}

.section,
.media-band,
.project-band {
  padding: clamp(56px, 8vw, 104px) clamp(18px, 6vw, 84px);
}

.section-heading {
  max-width: 760px;
  margin-bottom: 34px;
}

.intro-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(280px, 0.9fr);
  gap: clamp(26px, 5vw, 70px);
  align-items: end;
}

.intro-grid p:last-child {
  max-width: 720px;
  color: var(--muted);
  font-size: 1.08rem;
}

.stat-strip {
  display: grid;
  gap: 10px;
}

.stat-strip span {
  padding: 13px 16px;
  border-left: 5px solid var(--leaf);
  background: var(--white);
  box-shadow: 0 8px 24px rgba(20, 38, 31, 0.08);
  font-weight: 800;
}

.media-band {
  color: var(--white);
  background: #18342a;
}

.video-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px;
}

.video-grid article {
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 8px;
  overflow: hidden;
}

.video-grid video {
  aspect-ratio: 16 / 9;
  background: #07100d;
  object-fit: cover;
}

.video-grid h3,
.video-grid p {
  margin-left: 18px;
  margin-right: 18px;
}

.video-grid h3 {
  margin-top: 18px;
}

.video-grid p {
  color: rgba(255, 255, 255, 0.76);
  margin-bottom: 20px;
}

.timeline {
  display: grid;
  gap: 18px;
}

.timeline article {
  display: grid;
  grid-template-columns: 260px minmax(0, 1fr);
  gap: 24px;
  align-items: center;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
  box-shadow: 0 10px 28px rgba(20, 38, 31, 0.08);
}

.timeline img {
  aspect-ratio: 16 / 10;
  height: 100%;
  object-fit: cover;
  border-radius: 6px;
  background: #e7e2d7;
}

.step {
  display: inline-grid;
  place-items: center;
  width: 42px;
  height: 42px;
  margin-bottom: 10px;
  border-radius: 50%;
  background: var(--moss);
  color: var(--leaf);
  font-weight: 900;
}

.language {
  background: #edf1e6;
}

.tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 18px;
}

.tab {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 10px 14px;
  background: var(--white);
  color: var(--muted);
  font: inherit;
  font-weight: 800;
  cursor: pointer;
}

.tab.is-active {
  background: var(--leaf);
  color: var(--white);
  border-color: var(--leaf);
}

.tab-panel {
  display: none;
}

.tab-panel.is-active {
  display: block;
}

.card-grid,
.project-grid,
.link-grid,
.viewpoint-layout {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.card-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.mini-card,
.claim-card,
.project-grid article,
.link-grid a {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
  box-shadow: 0 10px 28px rgba(20, 38, 31, 0.08);
}

.mini-card,
.claim-card,
.project-grid article {
  padding: 20px;
}

.mini-card p,
.claim-card p,
.project-grid li,
.note {
  color: var(--muted);
}

.sentence-bank {
  display: grid;
  gap: 10px;
}

.sentence-bank p {
  margin: 0;
  padding: 16px 18px;
  border-radius: 8px;
  background: var(--white);
  border-left: 5px solid var(--water);
}

.status-scale {
  display: grid;
  grid-template-columns: repeat(7, minmax(0, 1fr));
  overflow: hidden;
  border-radius: 8px;
  border: 1px solid rgba(22, 33, 29, 0.18);
}

.status-scale span {
  min-height: 76px;
  display: grid;
  place-items: center;
  padding: 12px 8px;
  color: #15130d;
  text-align: center;
  font-weight: 900;
  font-size: 0.88rem;
}

.status-scale span:nth-child(1) { background: #81b29a; }
.status-scale span:nth-child(2) { background: #a7c957; }
.status-scale span:nth-child(3) { background: #f2c14e; }
.status-scale span:nth-child(4) { background: #f49d37; }
.status-scale span:nth-child(5) { background: #d96c4f; }
.status-scale span:nth-child(6) { background: #8d4b5c; color: white; }
.status-scale span:nth-child(7) { background: #2b2d33; color: white; }

.note {
  margin-top: 16px;
}

.claim-card img {
  margin: 4px 0 16px;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border-radius: 6px;
}

.claim-card ul {
  margin: 16px 0 0;
  padding-left: 20px;
  color: var(--muted);
}

.shuffle-btn,
.slogan-box button {
  background: var(--leaf);
  color: var(--white);
}

.prompt-output {
  min-height: 76px;
  margin: 16px 0 0;
  padding: 14px;
  border-radius: 8px;
  background: var(--moss);
  font-weight: 800;
}

.project-band {
  background:
    linear-gradient(rgba(13, 23, 19, 0.82), rgba(13, 23, 19, 0.82)),
    url("assets/ppt/image18.png") center / cover no-repeat;
  color: var(--white);
}

.project-grid article {
  background: rgba(255, 255, 255, 0.92);
  color: var(--ink);
}

.task-title {
  color: var(--clay);
  font-weight: 900;
}

.project-grid ol {
  padding-left: 20px;
}

.slogan-box {
  display: grid;
  gap: 16px;
}

.slogan-box p {
  min-height: 92px;
  display: grid;
  place-items: center;
  margin: 0;
  padding: 18px;
  border-radius: 8px;
  background: #f2ead8;
  color: var(--ink);
  text-align: center;
  font-size: 1.35rem;
  font-weight: 900;
  line-height: 1.2;
}

.link-grid a {
  display: grid;
  gap: 8px;
  min-height: 132px;
  padding: 20px;
  color: var(--muted);
}

.link-grid a:hover {
  border-color: var(--leaf);
  transform: translateY(-2px);
  transition: 160ms ease;
}

.link-grid a > span:first-child {
  color: var(--ink);
  font-size: 1.08rem;
  font-weight: 900;
}

.link-grid a > span:last-child {
  color: var(--muted);
  font-size: 1rem;
  font-weight: 400;
}

footer {
  padding: 26px clamp(18px, 6vw, 84px);
  background: #0d1713;
  color: rgba(255, 255, 255, 0.72);
}

footer p {
  margin: 0;
}

@media (max-width: 980px) {
  .intro-grid,
  .video-grid,
  .timeline article,
  .card-grid,
  .project-grid,
  .link-grid,
  .viewpoint-layout {
    grid-template-columns: 1fr 1fr;
  }

  .timeline article {
    align-items: start;
  }

  .status-scale {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (max-width: 680px) {
  .topbar {
    position: static;
    align-items: flex-start;
    flex-direction: column;
  }

  .topbar-controls {
    width: 100%;
    align-items: flex-start;
    flex-direction: column;
    gap: 12px;
  }

  .nav-links {
    width: 100%;
    overflow-x: auto;
    padding-bottom: 4px;
  }

  .language-picker {
    width: 100%;
    justify-content: space-between;
  }

  .language-picker select {
    max-width: 190px;
  }

  .hero {
    min-height: 82vh;
    padding-top: 54px;
  }

  .intro-grid,
  .video-grid,
  .timeline article,
  .card-grid,
  .project-grid,
  .link-grid,
  .viewpoint-layout {
    grid-template-columns: 1fr;
  }

  .timeline article {
    padding: 14px;
  }

  .timeline img {
    height: auto;
  }

  .status-scale {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}