:root {
  --ink: #122326;
  --muted: #5d6d72;
  --line: #d8e7de;
  --green: #1f8f61;
  --deep: #0c3f42;
  --orange: #ef7d1a;
  --blue: #1467a8;
  --wash: #f3f8f5;
  --white: #ffffff;
  --shadow: 0 18px 48px rgba(14, 47, 44, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

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

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

a {
  color: inherit;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 48px;
  background: rgba(255, 255, 255, 0.94);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(12px);
}

.brand {
  display: flex;
  gap: 16px;
  align-items: center;
  text-decoration: none;
}

.brand img {
  height: 38px;
  width: auto;
  object-fit: contain;
}

.topbar nav {
  display: flex;
  gap: 24px;
  color: var(--muted);
  font-size: 15px;
}

.topbar nav a {
  text-decoration: none;
}

.topbar nav a:hover {
  color: var(--green);
}

.hero {
  min-height: calc(100vh - 72px);
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(340px, 420px);
  gap: 54px;
  align-items: center;
  padding: 72px 7vw 56px;
  background: linear-gradient(180deg, #ffffff 0%, #f4faf7 100%);
}

.hero-copy {
  max-width: 820px;
}

.eyebrow,
.section-label {
  margin: 0 0 14px;
  color: var(--green);
  font-size: 13px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0;
}

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

h1 {
  margin-bottom: 24px;
  font-size: clamp(42px, 7vw, 76px);
  line-height: 1.04;
  letter-spacing: 0;
}

h2 {
  margin-bottom: 20px;
  font-size: clamp(30px, 4vw, 48px);
  line-height: 1.14;
  letter-spacing: 0;
}

h3 {
  margin-bottom: 10px;
  font-size: 22px;
  line-height: 1.24;
}

.lead {
  max-width: 720px;
  color: var(--muted);
  font-size: 22px;
  line-height: 1.72;
}

.hero-actions,
.download-row,
.download-stack {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.download-stack {
  flex-direction: column;
  align-items: flex-start;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 10px 18px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #fff;
  color: var(--deep);
  font-weight: 700;
  text-decoration: none;
}

.button.primary {
  background: var(--green);
  border-color: var(--green);
  color: #fff;
}

.button:hover {
  transform: translateY(-1px);
  box-shadow: 0 10px 24px rgba(31, 143, 97, 0.14);
}

.hero-media {
  margin: 0;
}

.hero-media img {
  width: 100%;
  max-height: 620px;
  object-fit: cover;
  object-position: center;
  border-radius: 8px;
  box-shadow: var(--shadow);
}

figcaption {
  margin-top: 10px;
  color: var(--muted);
  font-size: 14px;
}

.summary-band {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 1px;
  background: var(--line);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.summary-band div {
  padding: 34px 32px;
  background: var(--deep);
  color: #fff;
}

.summary-band strong {
  display: block;
  font-size: 42px;
  line-height: 1;
}

.summary-band span {
  display: block;
  margin-top: 8px;
  color: #dcece5;
  font-size: 16px;
}

.section {
  padding: 84px 7vw;
  border-bottom: 1px solid var(--line);
}

.section.split {
  display: grid;
  grid-template-columns: minmax(260px, 0.75fr) minmax(0, 1.25fr);
  gap: 64px;
  align-items: start;
}

.content-block {
  color: var(--muted);
  font-size: 20px;
}

.content-block strong {
  color: var(--ink);
}

.problem-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-top: 28px;
}

.problem-grid article {
  min-height: 210px;
  padding: 28px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--wash);
}

.problem-grid article:nth-child(2) {
  background: #f7f9fb;
  border-color: #dbe5ee;
}

.problem-grid article:nth-child(3) {
  background: #fff8ef;
  border-color: #f2dcc3;
}

.problem-grid p,
.section-head p,
.video-copy p {
  color: var(--muted);
  font-size: 18px;
}

.section-head {
  display: flex;
  justify-content: space-between;
  gap: 42px;
  align-items: end;
  margin-bottom: 30px;
}

.section-head > p {
  max-width: 520px;
  margin-bottom: 8px;
}

.fieldwork-section {
  background: #fbfdfc;
}

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

.field-gallery figure {
  margin: 0;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  overflow: hidden;
  box-shadow: 0 12px 30px rgba(14, 47, 44, 0.08);
}

.field-gallery img {
  width: 100%;
  aspect-ratio: 3 / 4;
  object-fit: contain;
  object-position: center;
  background: #f5f7f6;
}

.field-gallery figcaption {
  min-height: 120px;
  padding: 18px;
  font-size: 16px;
}

.field-gallery strong {
  display: block;
  color: var(--ink);
  font-size: 18px;
}

.tool-gallery {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.tool-gallery figure {
  margin: 0;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  overflow: hidden;
  box-shadow: 0 12px 30px rgba(14, 47, 44, 0.08);
}

.tool-gallery img {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  object-position: top center;
  background: #f5f7f6;
}

.tool-gallery figcaption {
  min-height: 128px;
  padding: 18px;
  font-size: 16px;
}

.tool-gallery strong {
  display: block;
  color: var(--ink);
  font-size: 18px;
}

.slide-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
}

.slide-grid img {
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: 0 12px 28px rgba(14, 47, 44, 0.08);
}

.article-section {
  background: var(--wash);
}

.video-section {
  background: #102326;
  color: #fff;
}

.video-section .section-label {
  color: #80d7b2;
}

.video-section .section-head p,
.video-copy p {
  color: #cad8d6;
}

.video-layout {
  display: grid;
  grid-template-columns: minmax(280px, 390px) minmax(0, 1fr);
  gap: 42px;
  align-items: center;
}

video {
  width: 100%;
  max-height: 720px;
  border-radius: 8px;
  background: #000;
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.32);
}

.video-copy {
  max-width: 640px;
}

.video-copy h3 {
  color: #fff;
}

.certificate-section {
  background: linear-gradient(180deg, #ffffff 0%, #f3faf6 100%);
}

.certificate-layout {
  display: grid;
  grid-template-columns: minmax(360px, 1.35fr) minmax(280px, 0.65fr);
  gap: 34px;
  align-items: start;
}

.certificate-preview {
  margin: 0;
}

.certificate-preview img {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.certificate-copy {
  padding: 26px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
}

.certificate-copy ul {
  margin: 0 0 26px;
  padding-left: 20px;
  color: var(--muted);
  font-size: 18px;
}

.certificate-copy p {
  color: var(--muted);
  font-size: 18px;
}

.profile-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 310px;
  gap: 28px;
}

.profile-image {
  margin: 0;
}

.profile-image img {
  width: 100%;
  aspect-ratio: 3 / 4;
  object-fit: cover;
  object-position: top center;
  border-radius: 8px;
  border: 1px solid var(--line);
}

footer {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  align-items: center;
  padding: 34px 7vw;
  background: #ffffff;
}

footer div {
  display: flex;
  gap: 18px;
  align-items: center;
}

footer img {
  height: 42px;
  width: auto;
}

footer p {
  margin: 0;
  color: var(--muted);
}

@media (max-width: 980px) {
  .topbar {
    height: auto;
    padding: 14px 22px;
    align-items: flex-start;
    flex-direction: column;
    gap: 10px;
  }

  .topbar nav {
    width: 100%;
    overflow-x: auto;
    gap: 18px;
    padding-bottom: 4px;
  }

  .hero,
  .section.split,
  .video-layout,
  .certificate-layout,
  .profile-grid {
    grid-template-columns: 1fr;
  }

  .hero {
    min-height: auto;
    padding-top: 48px;
  }

  .summary-band,
  .problem-grid,
  .field-gallery,
  .tool-gallery,
  .slide-grid {
    grid-template-columns: 1fr 1fr;
  }

  .section-head {
    display: block;
  }
}

@media (max-width: 620px) {
  .hero,
  .section {
    padding-left: 22px;
    padding-right: 22px;
  }

  h1 {
    font-size: 42px;
  }

  .lead,
  .content-block {
    font-size: 18px;
  }

  .summary-band,
  .problem-grid,
  .field-gallery,
  .tool-gallery,
  .slide-grid {
    grid-template-columns: 1fr;
  }

  footer {
    display: block;
  }

  footer p {
    margin-top: 16px;
  }
}