:root {
  --ink: #20282d;
  --ink-soft: #3f4c52;
  --muted: #728087;
  --paper: #f7f8f5;
  --surface: #ffffff;
  --surface-soft: #eef4f0;
  --line: #dfe6e1;
  --sage: #5f8d7a;
  --sage-deep: #2f6f5e;
  --rose: #c97872;
  --blue: #526f91;
  --amber: #b3813a;
  --shadow: 0 18px 42px rgba(31, 40, 45, 0.07);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

#top,
#cases,
#playbook,
#experience,
#skills,
#contact {
  scroll-margin-top: 92px;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family:
    -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", sans-serif;
  line-height: 1.7;
}

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

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  min-height: 68px;
  padding: 0 40px;
  border-bottom: 1px solid rgba(223, 230, 225, 0.9);
  background: rgba(255, 255, 255, 0.88);
  color: var(--ink);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-weight: 760;
  letter-spacing: 0;
  white-space: nowrap;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  border: 1px solid rgba(95, 141, 122, 0.28);
  border-radius: 8px;
  background: #f5faf7;
  color: var(--sage-deep);
  font-size: 0.82rem;
}

.brand-text {
  font-size: 0.98rem;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-links a {
  border-radius: 8px;
  padding: 8px 12px;
  color: var(--muted);
  font-size: 0.92rem;
  transition:
    background 180ms ease,
    color 180ms ease;
}

.nav-links a:hover,
.nav-links a.is-active {
  background: var(--surface-soft);
  color: var(--sage-deep);
}

.hero {
  position: relative;
  min-height: 78svh;
  overflow: hidden;
  border-bottom: 1px solid var(--line);
  background:
    linear-gradient(115deg, rgba(255, 255, 255, 0.98) 0%, rgba(247, 248, 245, 0.98) 58%, rgba(238, 244, 240, 0.94) 100%),
    #f7f8f5;
}

.hero-visual {
  position: absolute;
  right: clamp(-40px, 4vw, 72px);
  top: clamp(100px, 15vh, 150px);
  width: clamp(420px, 45vw, 690px);
  border-radius: 8px;
  box-shadow: 0 22px 54px rgba(52, 64, 61, 0.08);
  opacity: 0.96;
}

.hero-inner {
  position: relative;
  z-index: 1;
  width: min(1080px, calc(100% - 48px));
  margin: 0 auto;
  padding: 118px 0 68px;
}

.eyebrow,
.section-kicker {
  margin: 0 0 16px;
  color: var(--sage-deep);
  font-size: 0.78rem;
  font-weight: 780;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1,
h2,
h3,
h4,
p {
  margin-top: 0;
}

h1 {
  max-width: 730px;
  margin-bottom: 24px;
  font-size: 4rem;
  font-weight: 760;
  line-height: 1.12;
  letter-spacing: 0;
}

h2 {
  margin-bottom: 14px;
  font-size: 2.22rem;
  font-weight: 730;
  line-height: 1.25;
  letter-spacing: 0;
}

h3 {
  margin-bottom: 12px;
  font-size: 1.22rem;
  font-weight: 730;
  line-height: 1.4;
  letter-spacing: 0;
}

h4 {
  margin-bottom: 8px;
  font-size: 0.98rem;
  letter-spacing: 0;
}

.hero-copy {
  max-width: 660px;
  margin-bottom: 32px;
  color: var(--ink-soft);
  font-size: 1.13rem;
}

.hero-actions,
.contact-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  border: 1px solid transparent;
  border-radius: 8px;
  padding: 0 18px;
  font: inherit;
  font-weight: 720;
  cursor: pointer;
  transition:
    transform 180ms ease,
    border-color 180ms ease,
    background 180ms ease,
    color 180ms ease;
}

.button:hover {
  transform: translateY(-1px);
}

.button-primary {
  background: var(--sage-deep);
  color: #fff;
}

.button-primary:hover {
  background: #25584b;
}

.button-secondary {
  border-color: var(--line);
  background: rgba(255, 255, 255, 0.68);
  color: var(--ink);
}

.button-secondary:hover {
  border-color: rgba(95, 141, 122, 0.5);
  color: var(--sage-deep);
}

.button:disabled {
  cursor: not-allowed;
  opacity: 0.58;
  transform: none;
}

.hero-proof {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  max-width: 900px;
  margin: 58px 0 0;
  padding: 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.42);
}

.hero-proof div {
  min-height: 110px;
  padding: 22px 24px;
  border-right: 1px solid var(--line);
}

.hero-proof div:last-child {
  border-right: 0;
}

.hero-proof dt {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--ink);
  font-size: 1.9rem;
  font-weight: 800;
  line-height: 1;
  white-space: nowrap;
}

.metric-icon {
  display: inline-grid;
  flex: 0 0 28px;
  place-items: center;
  width: 28px;
  height: 28px;
  color: var(--sage-deep);
}

.metric-icon svg {
  width: 22px;
  height: 22px;
  stroke: currentColor;
  stroke-width: 1.8;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.hero-proof div:nth-child(2) .metric-icon {
  color: var(--blue);
}

.hero-proof div:nth-child(3) .metric-icon {
  color: var(--amber);
}

.hero-proof div:nth-child(4) .metric-icon {
  color: var(--rose);
}

.hero-proof dd {
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.section {
  padding: 88px 0;
}

.section-inner {
  width: min(1080px, calc(100% - 48px));
  margin: 0 auto;
}

.intro-section {
  border-bottom: 1px solid var(--line);
  background: var(--surface);
}

.intro-grid {
  display: grid;
  grid-template-columns: 0.85fr 1.15fr;
  gap: 64px;
  align-items: start;
}

.intro-grid p:last-child {
  color: var(--ink-soft);
  font-size: 1.06rem;
}

.section-heading {
  max-width: 720px;
  margin-bottom: 40px;
}

.section-heading p {
  color: var(--ink-soft);
}

.case-card {
  margin-bottom: 28px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.highlight-case {
  border-color: rgba(95, 141, 122, 0.34);
}

.case-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 18px;
  justify-content: space-between;
  padding: 17px 26px;
  border-bottom: 1px solid var(--line);
  background: #fbfcfb;
  color: var(--muted);
  font-size: 0.9rem;
  font-weight: 720;
}

.case-content {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 360px;
  gap: 34px;
  padding: 30px 26px;
}

.case-content p {
  color: var(--ink-soft);
}

.case-metrics {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0;
  margin: 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.case-metrics div {
  min-height: 108px;
  padding: 15px 14px;
  border-right: 1px solid var(--line);
}

.case-metrics div:last-child {
  border-right: 0;
}

.case-metrics dt {
  color: var(--sage-deep);
  font-size: 1.34rem;
  font-weight: 800;
  line-height: 1.1;
}

.case-metrics dd {
  margin: 8px 0 0;
  color: var(--muted);
  font-size: 0.86rem;
  line-height: 1.45;
}

.case-breakdown {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  border-top: 1px solid var(--line);
}

.case-breakdown section {
  min-height: 172px;
  padding: 24px 22px;
  border-right: 1px solid var(--line);
}

.case-breakdown section:nth-child(1) h4 {
  color: var(--blue);
}

.case-breakdown section:nth-child(2) h4 {
  color: var(--amber);
}

.case-breakdown section:nth-child(3) h4 {
  color: var(--sage-deep);
}

.case-breakdown section:nth-child(4) h4 {
  color: var(--rose);
}

.case-breakdown section:last-child {
  border-right: 0;
}

.case-breakdown p {
  margin-bottom: 0;
  color: var(--ink-soft);
  font-size: 0.92rem;
}

.playbook-section,
.skills-section {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: #f0f5f1;
}

.playbook-grid,
.skills-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
}

.playbook-item,
.skills-grid article {
  min-height: 226px;
  border: 1px solid rgba(95, 141, 122, 0.18);
  border-radius: 8px;
  padding: 23px;
  background: rgba(255, 255, 255, 0.72);
}

.playbook-item span {
  display: inline-block;
  margin-bottom: 30px;
  color: var(--rose);
  font-size: 0.9rem;
  font-weight: 800;
}

.playbook-item p,
.skills-grid p {
  color: var(--ink-soft);
}

.experience-layout {
  display: grid;
  grid-template-columns: 330px minmax(0, 1fr);
  gap: 60px;
}

.sticky-heading {
  position: sticky;
  top: 110px;
  align-self: start;
  margin-bottom: 0;
}

.timeline {
  border-left: 1px solid var(--line);
}

.timeline-item {
  position: relative;
  padding: 0 0 40px 30px;
}

.timeline-item:last-child {
  padding-bottom: 0;
}

.timeline-item::before {
  content: "";
  position: absolute;
  top: 7px;
  left: -5px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--sage);
}

.timeline-item time {
  display: inline-block;
  margin-bottom: 10px;
  color: var(--rose);
  font-size: 0.9rem;
  font-weight: 780;
}

.timeline-item p {
  color: var(--ink-soft);
}

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

.skills-grid article {
  min-height: 164px;
}

.contact-section {
  padding: 84px 0;
  background: #24302f;
  color: #fff;
}

.contact-inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 370px;
  gap: 48px;
  align-items: center;
}

.contact-inner h2 {
  max-width: 720px;
}

.contact-inner p {
  color: rgba(255, 255, 255, 0.76);
}

.contact-panel {
  border: 1px solid rgba(255, 255, 255, 0.16);
  border-radius: 8px;
  padding: 24px;
  background: rgba(255, 255, 255, 0.07);
}

.contact-panel p {
  margin-bottom: 12px;
}

.contact-panel strong {
  color: #fff;
}

.copy-feedback {
  min-height: 26px;
  margin: 14px 0 0;
  color: #b8dfd1;
  font-size: 0.92rem;
}

.site-footer {
  padding: 22px 24px;
  border-top: 1px solid var(--line);
  background: var(--surface);
  color: var(--muted);
  text-align: center;
  font-size: 0.9rem;
}

@media (max-width: 980px) {
  .site-header {
    align-items: flex-start;
    min-height: auto;
    padding: 15px 24px;
    gap: 14px;
  }

  .nav-links {
    flex-wrap: wrap;
    justify-content: flex-end;
  }

  .hero {
    min-height: auto;
  }

  .hero-inner {
    padding: 86px 0 58px;
  }

  .hero-visual {
    right: -170px;
    top: 118px;
    width: 590px;
    opacity: 0.56;
  }

  h1 {
    max-width: 680px;
    font-size: 3rem;
  }

  h2 {
    font-size: 1.96rem;
  }

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

  .hero-proof div:nth-child(2n) {
    border-right: 0;
  }

  .hero-proof div:nth-child(-n + 2) {
    border-bottom: 1px solid var(--line);
  }

  .intro-grid,
  .case-content,
  .experience-layout,
  .contact-inner {
    grid-template-columns: 1fr;
  }

  .case-metrics,
  .case-breakdown,
  .playbook-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .case-breakdown section:nth-child(2n) {
    border-right: 0;
  }

  .case-breakdown section:nth-child(-n + 2) {
    border-bottom: 1px solid var(--line);
  }

  .sticky-heading {
    position: static;
  }
}

@media (max-width: 720px) {
  .site-header {
    flex-wrap: nowrap;
    align-items: center;
    min-height: 62px;
    padding: 13px 16px;
    gap: 12px;
    overflow-x: auto;
  }

  .brand {
    flex: 0 0 auto;
  }

  .brand-mark {
    width: 34px;
    height: 34px;
  }

  .brand-text {
    display: none;
  }

  .nav-links {
    flex: 1 1 auto;
    flex-wrap: nowrap;
    justify-content: flex-end;
    overflow-x: auto;
    gap: 2px;
  }

  .nav-links a {
    padding: 7px 8px;
    font-size: 0.86rem;
    white-space: nowrap;
  }

  .hero-visual {
    right: -225px;
    top: 102px;
    width: 520px;
    opacity: 0.42;
  }

  .hero-inner,
  .section-inner {
    width: min(100% - 32px, 1080px);
  }

  .hero-inner {
    padding: 56px 0 34px;
  }

  .eyebrow,
  .section-kicker {
    font-size: 0.74rem;
  }

  h1 {
    max-width: 340px;
    font-size: 2.28rem;
  }

  h2 {
    font-size: 1.68rem;
  }

  .hero-copy {
    max-width: 350px;
    font-size: 1rem;
  }

  .hero-actions,
  .contact-actions {
    flex-direction: column;
  }

  .button {
    width: 100%;
  }

  .hero-proof {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    margin-top: 28px;
  }

  .hero-proof div {
    min-height: 94px;
    padding: 18px;
  }

  .hero-proof dt {
    font-size: 1.7rem;
  }

  .section {
    padding: 64px 0;
  }

  .case-meta,
  .case-content {
    padding-left: 18px;
    padding-right: 18px;
  }

  .case-metrics,
  .case-breakdown,
  .playbook-grid,
  .skills-grid {
    grid-template-columns: 1fr;
  }

  .case-metrics div,
  .case-metrics div:last-child {
    min-height: auto;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .case-metrics div:last-child {
    border-bottom: 0;
  }

  .case-breakdown section,
  .case-breakdown section:nth-child(2n) {
    min-height: auto;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .case-breakdown section:last-child {
    border-bottom: 0;
  }

  .timeline {
    margin-left: 8px;
  }

  .timeline-item {
    padding-left: 24px;
  }

  .contact-section {
    padding: 64px 0;
  }

  .contact-panel {
    padding: 20px;
  }
}