:root {
  --navy: #17385f;
  --blue: #244f8f;
  --blue-dark: #1d447e;
  --teal: #2a8a85;
  --surface: #f4f7fa;
  --line: #d6e0ea;
  --line-strong: #bccbd9;
  --text: #203a55;
  --muted: #64788d;
  --white: #fff;
  --shadow: 0 12px 34px rgba(26, 56, 87, .09);
  font-family: "Microsoft YaHei", "PingFang SC", system-ui, sans-serif;
  color: var(--text);
  background: var(--surface);
  font-synthesis: none;
}

* { box-sizing: border-box; }
html { min-width: 320px; min-height: 100%; background: var(--surface); }
body { min-height: 100vh; margin: 0; color: var(--text); background: var(--surface); }
a { color: inherit; }

.site-header {
  display: flex;
  align-items: center;
  min-height: 68px;
  padding: 10px max(24px, calc((100vw - 1180px) / 2));
  border-bottom: 1px solid var(--line);
  background: var(--white);
}
.brand {
  display: flex;
  align-items: center;
  gap: 11px;
  color: var(--navy);
  text-decoration: none;
}
.brand-mark {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border-radius: 8px;
  background: var(--navy);
  color: var(--white);
  font-weight: 800;
  letter-spacing: -.04em;
}
.brand > span:last-child { display: grid; gap: 1px; }
.brand strong { font-size: 15px; }
.brand small { color: var(--muted); font-size: 11px; }

main {
  width: min(1180px, calc(100% - 48px));
  margin: 0 auto;
  padding: 32px 0 36px;
}
.hero {
  display: grid;
  grid-template-columns: minmax(360px, .92fr) minmax(520px, 1.08fr);
  gap: 44px;
  align-items: center;
  min-height: 205px;
  padding: 34px 40px;
  border-radius: 14px;
  background:
    radial-gradient(circle at 98% 0, rgba(98, 190, 208, .18), transparent 36%),
    linear-gradient(125deg, #16385f, #214d7d);
  color: var(--white);
  box-shadow: 0 14px 38px rgba(23, 56, 95, .16);
}
.eyebrow {
  margin: 0 0 6px;
  color: #64c4c0;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: .15em;
}
.hero h1 {
  margin: 0;
  font-size: clamp(27px, 3vw, 38px);
  line-height: 1.25;
}
.hero-copy > p:last-child {
  max-width: 560px;
  margin: 13px 0 0;
  color: #d4e0eb;
  font-size: 15px;
  line-height: 1.8;
}
.flow-path {
  display: grid;
  grid-template-columns: auto 1fr auto 1fr auto 1fr auto;
  align-items: center;
  gap: 10px;
}
.flow-path span {
  display: grid;
  justify-items: center;
  gap: 8px;
  color: #e4edf5;
  font-size: 12px;
  white-space: nowrap;
}
.flow-path b {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border: 1px solid rgba(255, 255, 255, .42);
  border-radius: 50%;
  background: rgba(255, 255, 255, .09);
  color: var(--white);
  font-size: 12px;
}
.flow-path i {
  height: 1px;
  background: rgba(255, 255, 255, .34);
}

.labs-section { padding: 36px 0 0; }
.section-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 30px;
  margin-bottom: 18px;
}
.section-heading h2 {
  margin: 0;
  color: var(--navy);
  font-size: 25px;
}
.section-heading > p {
  max-width: 540px;
  margin: 0 0 2px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.7;
  text-align: right;
}
.lab-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}
.lab-card {
  display: grid;
  min-height: 272px;
  padding: 24px 25px 20px;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--white);
  box-shadow: 0 5px 20px rgba(26, 56, 87, .035);
  text-decoration: none;
  transition: transform .16s, border-color .16s, box-shadow .16s;
}
.lab-card:hover {
  transform: translateY(-3px);
  border-color: #9fb4c7;
  box-shadow: var(--shadow);
}
.lab-card:focus-visible,
.brand:focus-visible {
  outline: 3px solid rgba(36, 79, 143, .22);
  outline-offset: 3px;
}
.card-top {
  display: flex;
  align-items: start;
  justify-content: space-between;
  min-height: 64px;
}
.lab-number {
  color: #a8b6c5;
  font-size: 15px;
  font-weight: 800;
  letter-spacing: .08em;
}
.lab-icon {
  display: grid;
  place-items: center;
  width: 62px;
  height: 62px;
  border-radius: 10px;
  background: #eef4f8;
  color: var(--blue);
}
.lab-icon svg {
  width: 42px;
  height: 42px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.lab-icon .accent { stroke: var(--teal); }
.lab-icon .fill { fill: rgba(42, 138, 133, .17); }
.lab-type {
  margin: 3px 0 4px;
  color: var(--teal);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: .08em;
}
.card-copy h3 {
  margin: 0;
  color: var(--navy);
  font-size: 22px;
}
.card-copy > p:last-child {
  margin: 10px 0 20px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.75;
}
.card-meta {
  align-self: end;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding-top: 14px;
  border-top: 1px solid #e5ebf1;
  color: var(--muted);
  font-size: 12px;
}
.card-meta strong { color: var(--navy); }
.enter {
  color: var(--blue);
  font-weight: 800;
  white-space: nowrap;
}
.enter b {
  display: inline-block;
  margin-left: 5px;
  transition: transform .16s;
}
.lab-card:hover .enter b { transform: translateX(3px); }
.hydrostatic .lab-icon { background: #edf6f4; color: #357a79; }
.bernoulli .lab-icon { background: #eef2fa; color: #365f9a; }
.resistance .lab-icon { background: #f3f1f8; color: #60538e; }

.notice {
  display: flex;
  gap: 13px;
  align-items: start;
  margin-top: 22px;
  padding: 17px 20px;
  border: 1px solid #cfe0e5;
  border-radius: 10px;
  background: #f2f8f8;
}
.notice-icon {
  display: grid;
  flex: 0 0 auto;
  place-items: center;
  width: 25px;
  height: 25px;
  border-radius: 50%;
  background: var(--teal);
  color: var(--white);
  font-family: Georgia, serif;
  font-weight: 700;
}
.notice strong { color: var(--navy); font-size: 13px; }
.notice p { margin: 3px 0 0; color: var(--muted); font-size: 12px; line-height: 1.65; }
.site-footer {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  width: min(1180px, calc(100% - 48px));
  margin: 0 auto;
  padding: 20px 0 26px;
  border-top: 1px solid var(--line);
  color: #8292a2;
  font-size: 11px;
}
.site-footer a { color: inherit; text-decoration: none; }
.site-footer a:hover { color: var(--navy); text-decoration: underline; }

@media (max-width: 960px) {
  .hero { grid-template-columns: 1fr; gap: 26px; }
  .flow-path { max-width: 640px; }
}

@media (max-width: 720px) {
  .site-header { padding-inline: 18px; }
  .brand strong { font-size: 14px; }
  main { width: min(100% - 28px, 620px); padding-top: 18px; }
  .hero { min-height: 0; padding: 27px 23px; }
  .hero-copy > p:last-child { font-size: 14px; }
  .flow-path { grid-template-columns: repeat(4, 1fr); gap: 7px; }
  .flow-path i { display: none; }
  .flow-path span { font-size: 10px; }
  .flow-path b { width: 36px; height: 36px; }
  .labs-section { padding-top: 28px; }
  .section-heading { display: block; }
  .section-heading > p { margin-top: 8px; text-align: left; }
  .lab-grid { grid-template-columns: 1fr; }
  .lab-card { min-height: 258px; padding: 21px; }
  .site-footer { width: min(100% - 28px, 620px); flex-direction: column; gap: 4px; }
}

@media (max-width: 430px) {
  .brand small { display: none; }
  .brand-mark { width: 36px; height: 36px; }
  .hero h1 { font-size: 26px; }
  .flow-path span { white-space: normal; text-align: center; }
  .card-meta { align-items: end; }
}