:root {
  --ink: #111820;
  --navy: #111c2d;
  --navy-soft: #1a2b42;
  --paper: #e7eef1;
  --paper-bright: #f7fafb;
  --muted: #60707a;
  --line: #b8c5ca;
  --orange: #f26a3d;
  --orange-dark: #c94e28;
  --mint: #72d8c2;
  --blue: #6aa9ff;
  --max: 1240px;
  --shadow: 0 18px 46px rgba(17, 24, 32, 0.13);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 86px;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: "Microsoft YaHei", "PingFang SC", "Noto Sans CJK SC", sans-serif;
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

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

[hidden] {
  display: none !important;
}

a {
  color: inherit;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

:focus-visible {
  outline: 3px solid var(--orange);
  outline-offset: 4px;
}

.skip-link {
  position: fixed;
  z-index: 100;
  top: 12px;
  left: 12px;
  padding: 10px 14px;
  color: white;
  background: var(--ink);
  transform: translateY(-180%);
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header {
  position: sticky;
  z-index: 20;
  top: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 74px;
  padding: 12px max(24px, calc((100vw - var(--max)) / 2));
  border-bottom: 1px solid rgba(17, 24, 32, 0.15);
  background: rgba(231, 238, 241, 0.93);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 43px;
  height: 43px;
  place-items: center;
  color: white;
  background: var(--navy);
  font: 700 15px/1 Consolas, monospace;
  letter-spacing: -0.04em;
}

.brand-copy {
  display: grid;
  font: 700 14px/1.1 Consolas, monospace;
  letter-spacing: 0.08em;
}

.brand-copy small {
  margin-top: 5px;
  color: var(--muted);
  font-size: 10px;
  letter-spacing: 0.18em;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: clamp(18px, 3vw, 38px);
}

.site-nav a {
  position: relative;
  text-decoration: none;
  font-size: 14px;
  font-weight: 700;
}

.site-nav a::after {
  position: absolute;
  right: 0;
  bottom: -7px;
  left: 0;
  height: 2px;
  content: "";
  background: var(--orange);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 180ms ease;
}

.site-nav a:hover::after {
  transform: scaleX(1);
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(330px, 0.65fr);
  gap: clamp(48px, 8vw, 116px);
  align-items: end;
  width: min(var(--max), calc(100% - 48px));
  min-height: calc(100vh - 74px);
  margin: 0 auto;
  padding: clamp(76px, 11vw, 150px) 0 84px;
}

.eyebrow,
.section-code,
.case-index,
.board-label {
  margin: 0;
  color: var(--orange-dark);
  font: 700 12px/1.4 Consolas, monospace;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

.hero h1 {
  max-width: 900px;
  margin: 18px 0 30px;
  font-family: "Microsoft YaHei", "Arial Black", sans-serif;
  font-size: clamp(3.45rem, 7.2vw, 7.8rem);
  font-weight: 900;
  line-height: 0.98;
  letter-spacing: -0.075em;
}

.hero h1 span {
  display: inline-block;
  color: var(--orange);
  letter-spacing: -0.08em;
}

.hero-intro {
  max-width: 680px;
  margin: 0;
  color: #394951;
  font-size: clamp(1rem, 1.7vw, 1.22rem);
  line-height: 1.85;
}

.hero-actions,
.about-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 34px;
}

.button {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  padding: 0 22px;
  border: 1px solid transparent;
  text-decoration: none;
  font-size: 15px;
  font-weight: 700;
  transition: transform 160ms ease, background-color 160ms ease, color 160ms ease;
}

.button:hover {
  transform: translateY(-2px);
}

.button-primary {
  color: white;
  background: var(--orange);
}

.button-primary:hover {
  background: var(--orange-dark);
}

.button-quiet {
  border-color: #9daeb5;
  background: transparent;
}

.button-quiet:hover {
  background: var(--paper-bright);
}

.button-dark {
  color: white;
  background: var(--navy);
}

.hero-board {
  position: relative;
  padding: 24px 0 0;
  border-top: 5px solid var(--navy);
}

.hero-board::before {
  position: absolute;
  top: -5px;
  right: 0;
  width: 72px;
  height: 5px;
  content: "";
  background: var(--orange);
}

.board-label {
  margin-bottom: 28px;
  color: var(--muted);
}

.board-line {
  display: grid;
  grid-template-columns: 94px 1fr;
  align-items: center;
  min-height: 108px;
  border-top: 1px solid var(--line);
}

.board-line strong {
  color: var(--navy);
  font: 700 clamp(2.8rem, 5vw, 4.6rem)/1 Consolas, monospace;
  letter-spacing: -0.08em;
}

.board-line span {
  color: #37474f;
  font: 700 12px/1.65 Consolas, monospace;
  letter-spacing: 0.08em;
}

.hero-board > p {
  margin: 24px 0 0;
  color: var(--muted);
  font-size: 14px;
}

.demo-stage {
  overflow: hidden;
  padding: 104px max(24px, calc((100vw - var(--max)) / 2)) 126px;
  color: #eff5f7;
  background:
    linear-gradient(rgba(255,255,255,0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.035) 1px, transparent 1px),
    var(--navy);
  background-size: 44px 44px;
}

.section-heading {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(280px, 470px);
  gap: 40px;
  align-items: end;
  width: min(var(--max), 100%);
  margin: 0 auto 62px;
}

.section-heading h2,
.about-lead h2 {
  margin: 8px 0 0;
  font-size: clamp(2.5rem, 5.2vw, 5.4rem);
  font-weight: 900;
  line-height: 1.05;
  letter-spacing: -0.055em;
}

.section-heading > p {
  margin: 0;
  color: var(--muted);
}

.section-heading-light .section-code,
.demo-stage .case-index {
  color: var(--mint);
}

.section-heading-light > p {
  color: #aebbc4;
}

.demo-case {
  display: grid;
  grid-template-columns: minmax(290px, 0.38fr) minmax(0, 0.62fr);
  gap: clamp(36px, 6vw, 86px);
  align-items: center;
  width: min(var(--max), 100%);
  margin: 0 auto;
  padding: 72px 0;
  border-top: 1px solid rgba(255,255,255,0.16);
}

.demo-case-reverse .demo-copy {
  order: 2;
}

.demo-copy h3,
.proposal-copy h3,
.analysis-card h3 {
  margin: 12px 0 6px;
  font-size: clamp(2rem, 4vw, 4.3rem);
  line-height: 1.08;
  letter-spacing: -0.045em;
}

.case-type {
  margin: 0;
  color: var(--mint);
  font: 700 13px/1.5 Consolas, monospace;
  letter-spacing: 0.04em;
}

.case-summary {
  margin: 26px 0 30px;
  color: #c5d0d6;
  font-size: 17px;
}

.case-facts {
  margin: 0;
}

.case-facts div {
  display: grid;
  grid-template-columns: 92px 1fr;
  gap: 16px;
  padding: 12px 0;
  border-top: 1px solid rgba(255,255,255,0.13);
}

.case-facts dt {
  color: #82929c;
  font-size: 13px;
}

.case-facts dd {
  margin: 0;
  color: #eff5f7;
  font-size: 14px;
}

.video-shell {
  position: relative;
  overflow: hidden;
  border: 1px solid rgba(255,255,255,0.18);
  background: #070c13;
  box-shadow: 0 28px 80px rgba(0, 0, 0, 0.35);
}

.video-shell::before {
  display: block;
  padding-top: 56.25%;
  content: "";
}

.video-shell video,
.video-shell iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

.video-shell video {
  object-fit: contain;
}

.video-error {
  position: absolute;
  right: 16px;
  bottom: 16px;
  left: 16px;
  z-index: 2;
  margin: 0;
  padding: 12px 14px;
  color: #fce8df;
  background: rgba(95, 31, 15, 0.9);
  font-size: 13px;
}

.proposal-section,
.analysis-section {
  width: min(var(--max), calc(100% - 48px));
  margin: 0 auto;
  padding: 112px 0;
}

.proposal-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 28px;
}

.proposal-card {
  display: grid;
  grid-template-columns: minmax(190px, 0.42fr) minmax(0, 0.58fr);
  min-height: 480px;
  border: 1px solid var(--line);
  background: var(--paper-bright);
  box-shadow: var(--shadow);
}

.proposal-cover {
  position: relative;
  overflow: hidden;
  min-height: 360px;
  background: #d4dde0;
}

.proposal-cover img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
  transition: transform 380ms cubic-bezier(.2,.8,.2,1);
}

.proposal-cover:hover img {
  transform: scale(1.025);
}

.proposal-copy {
  display: flex;
  flex-direction: column;
  padding: 34px 30px 28px;
}

.proposal-copy h3 {
  font-size: clamp(2rem, 3.2vw, 3.7rem);
}

.proposal-copy > p:not(.case-index) {
  color: #47575f;
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  margin: 16px 0 30px;
  padding: 0;
  list-style: none;
}

.tag-list li,
.card-meta span {
  padding: 5px 9px;
  color: #36554e;
  background: #d8eee9;
  font-size: 12px;
  font-weight: 700;
}

.text-link {
  margin-top: auto;
  color: var(--orange-dark);
  font-weight: 700;
  text-decoration-thickness: 1px;
  text-underline-offset: 5px;
}

.analysis-section {
  padding-top: 46px;
}

.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: -24px 0 30px;
}

.filter-button {
  min-height: 42px;
  padding: 0 15px;
  border: 1px solid #9babb1;
  color: var(--ink);
  background: transparent;
  font: 700 14px/1 "Microsoft YaHei", sans-serif;
  cursor: pointer;
}

.filter-button:hover,
.filter-button.is-active {
  color: white;
  border-color: var(--navy);
  background: var(--navy);
}

.analysis-grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  border-top: 1px solid #8999a0;
  border-left: 1px solid #8999a0;
}

.analysis-card {
  position: relative;
  grid-column: span 6;
  display: flex;
  min-height: 380px;
  flex-direction: column;
  padding: clamp(28px, 4vw, 48px);
  border-right: 1px solid #8999a0;
  border-bottom: 1px solid #8999a0;
  background: rgba(247, 250, 251, 0.58);
}

.analysis-card:nth-child(2),
.analysis-card:nth-child(3) {
  background: rgba(255,255,255,0.84);
}

.analysis-card-wide {
  grid-column: span 12;
  min-height: 330px;
}

.analysis-card[hidden] {
  display: none;
}

.analysis-card h3 {
  max-width: 560px;
  margin-top: 18px;
  font-size: clamp(1.7rem, 3.1vw, 3rem);
}

.analysis-card > p:not(.case-index) {
  max-width: 650px;
  color: #47575f;
}

.card-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  margin: 14px 0 30px;
}

.card-link {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: auto;
  padding-top: 18px;
  border-top: 1px solid var(--line);
  color: var(--orange-dark);
  text-decoration: none;
  font-weight: 700;
}

.card-link span {
  font-size: 24px;
  transition: transform 160ms ease;
}

.card-link:hover span {
  transform: translate(3px, -3px);
}

.about-section {
  display: grid;
  grid-template-columns: minmax(300px, 0.42fr) minmax(0, 0.58fr);
  gap: clamp(50px, 9vw, 130px);
  padding: 112px max(24px, calc((100vw - var(--max)) / 2));
  color: #eef4f6;
  background: var(--navy-soft);
}

.about-lead .section-code {
  color: var(--mint);
}

.about-lead h2 {
  margin-bottom: 28px;
}

.about-lead > p:last-child {
  color: #b8c5cc;
  font-size: 17px;
}

.about-details {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 44px;
}

.about-block {
  padding: 24px 0;
  border-top: 1px solid rgba(255,255,255,0.18);
}

.about-block:first-child {
  grid-row: span 2;
}

.about-block h3 {
  margin: 0 0 18px;
  color: var(--mint);
  font: 700 13px/1.4 Consolas, monospace;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.about-block p,
.about-block ul {
  margin: 0 0 18px;
  color: #c7d1d6;
}

.about-block strong {
  color: white;
}

.about-block ul {
  padding-left: 1.2em;
}

.about-actions {
  grid-column: 1 / -1;
}

.site-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 88px;
  padding: 20px max(24px, calc((100vw - var(--max)) / 2));
  border-top: 1px solid rgba(255,255,255,0.12);
  color: #9eacb4;
  background: var(--navy);
  font: 700 12px/1.5 Consolas, monospace;
  letter-spacing: 0.1em;
}

.site-footer a {
  color: white;
  text-decoration: none;
}

@media (max-width: 1050px) {
  .hero {
    grid-template-columns: 1fr;
    min-height: auto;
  }

  .hero-board {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0 22px;
  }

  .board-label,
  .hero-board > p {
    grid-column: 1 / -1;
  }

  .board-line {
    grid-template-columns: 76px 1fr;
  }

  .proposal-grid {
    grid-template-columns: 1fr;
  }

  .proposal-card {
    grid-template-columns: minmax(230px, 0.37fr) 1fr;
  }
}

@media (max-width: 800px) {
  .site-header {
    min-height: 66px;
  }

  .brand-copy {
    display: none;
  }

  .site-nav {
    gap: 16px;
  }

  .site-nav a {
    font-size: 13px;
  }

  .hero {
    width: min(100% - 32px, var(--max));
    padding-top: 68px;
  }

  .hero h1 {
    font-size: clamp(3rem, 14vw, 5.2rem);
  }

  .section-heading,
  .demo-case,
  .about-section {
    grid-template-columns: 1fr;
  }

  .section-heading {
    gap: 18px;
  }

  .demo-case-reverse .demo-copy {
    order: 0;
  }

  .analysis-card,
  .analysis-card-wide {
    grid-column: span 12;
  }

  .about-details {
    grid-template-columns: 1fr;
  }

  .about-block:first-child,
  .about-actions {
    grid-column: auto;
    grid-row: auto;
  }
}

@media (max-width: 600px) {
  html {
    scroll-padding-top: 64px;
  }

  .site-header {
    padding-right: 16px;
    padding-left: 16px;
  }

  .site-nav a:nth-child(4) {
    display: none;
  }

  .hero {
    padding: 52px 0 64px;
  }

  .hero h1 {
    letter-spacing: -0.065em;
  }

  .hero-board {
    grid-template-columns: 1fr;
  }

  .board-line {
    grid-template-columns: 82px 1fr;
  }

  .demo-stage {
    padding: 74px 16px 88px;
  }

  .demo-case {
    gap: 28px;
    padding: 54px 0;
  }

  .case-facts div {
    grid-template-columns: 78px 1fr;
  }

  .proposal-section,
  .analysis-section {
    width: min(100% - 32px, var(--max));
    padding-top: 78px;
    padding-bottom: 78px;
  }

  .proposal-card {
    grid-template-columns: 1fr;
  }

  .proposal-cover {
    min-height: 280px;
    max-height: 410px;
  }

  .proposal-copy,
  .analysis-card {
    padding: 26px 22px;
  }

  .analysis-card {
    min-height: 340px;
  }

  .about-section {
    padding: 78px 20px;
  }

  .site-footer {
    align-items: flex-start;
    flex-direction: column;
    gap: 10px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }

}