:root {
  --deep: #12353b;
  --card: #1a4a52;
  --ink: #e7f3f0;
  --dim: #9cb8b4;
  --mint: #a8e6cf;
  --line: #2a5d66;
  --foot: #0b2226;
  --soft: #164249;
  --radius: 16px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: auto;
}

body {
  margin: 0;
  font-family: "Avenir Next", "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--deep);
  color: var(--ink);
  line-height: 1.8;
  font-size: 16px;
}

svg {
  display: block;
}

a {
  color: var(--mint);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.mast {
  background: #0f2e33;
  position: sticky;
  top: 0;
  z-index: 20;
}

.mast-row {
  max-width: 1180px;
  margin: 0 auto;
  padding: 16px 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
}

.brand {
  font-weight: 700;
  color: var(--ink);
  font-size: 15px;
}

.menu {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  justify-content: flex-end;
}

.menu a {
  color: #c5ddd9;
  font-size: 13px;
  padding-bottom: 4px;
  border-bottom: 2px solid transparent;
  text-decoration: none;
}

.menu a:hover {
  color: var(--mint);
  border-bottom-color: var(--mint);
  text-decoration: none;
}

.lead {
  background: linear-gradient(180deg, #0f2e33 0%, var(--deep) 100%);
  padding: 56px 28px 28px;
}

.lead-inner {
  max-width: 1180px;
  margin: 0 auto;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--mint);
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.lead h1 {
  margin: 0 0 18px;
  font-size: 32px;
  line-height: 1.32;
  max-width: 18em;
}

.lead p {
  margin: 0 0 12px;
  max-width: 46em;
  color: var(--dim);
}

.trio {
  max-width: 1180px;
  margin: 0 auto;
  padding: 8px 28px 12px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.tile {
  background: var(--card);
  border-radius: var(--radius);
  padding: 22px 20px 20px;
  min-height: 168px;
}

.tile svg {
  width: 48px;
  height: 48px;
  margin-bottom: 14px;
}

.tile h3 {
  margin: 0 0 8px;
  font-size: 17px;
}

.tile p {
  margin: 0;
  color: var(--dim);
  font-size: 14px;
}

.main {
  max-width: 1180px;
  margin: 0 auto;
  padding: 20px 28px 72px;
}

.mod {
  padding: 28px 0 12px;
}

.mod h2 {
  margin: 0 0 14px;
  font-size: 24px;
  line-height: 1.4;
}

.mod p {
  margin: 0 0 12px;
  color: #d5e8e4;
}

.pair {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 18px;
  margin: 18px 0 6px;
}

.box {
  background: var(--card);
  border-radius: var(--radius);
  padding: 22px 22px 18px;
}

.box h3 {
  margin: 0 0 10px;
  font-size: 16px;
  color: var(--mint);
}

.box p {
  margin: 0;
  color: var(--dim);
}

.ladder {
  margin: 20px 0 0;
  padding: 0;
  list-style: none;
  counter-reset: desk;
}

.ladder li {
  display: grid;
  grid-template-columns: 72px 1fr;
  gap: 16px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}

.ladder li:last-child {
  border-bottom: 0;
}

.ladder li::before {
  counter-increment: desk;
  content: counter(desk, decimal-leading-zero);
  font-size: 40px;
  line-height: 1;
  color: rgba(168, 230, 207, 0.35);
  font-weight: 700;
}

.ladder h3 {
  margin: 0 0 6px;
  font-size: 17px;
}

.ladder p {
  margin: 0;
  color: var(--dim);
}

.matrix {
  width: 100%;
  border-collapse: collapse;
  margin-top: 16px;
  background: var(--card);
  border-radius: var(--radius);
  overflow: hidden;
  font-size: 14px;
}

.matrix th,
.matrix td {
  padding: 14px 16px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--line);
}

.matrix th {
  background: var(--soft);
  color: var(--mint);
  font-weight: 600;
}

.matrix tr:last-child td {
  border-bottom: 0;
}

.ask details {
  background: var(--card);
  border-radius: var(--radius);
  margin: 0 0 12px;
  padding: 4px 4px 0;
}

.ask summary {
  cursor: pointer;
  padding: 14px 18px;
  font-weight: 600;
  list-style: none;
}

.ask summary::-webkit-details-marker {
  display: none;
}

.ask details[open] summary {
  color: var(--mint);
}

.ask details p {
  margin: 0;
  padding: 0 18px 16px;
  color: var(--dim);
}

.base {
  background: var(--foot);
  color: #7f9a96;
  font-size: 13px;
}

.base-inner {
  max-width: 1180px;
  margin: 0 auto;
  padding: 32px 28px 40px;
}

.base p {
  margin: 0 0 8px;
}

.base p:last-child {
  margin-bottom: 0;
}

@media (max-width: 900px) {
  .trio,
  .pair {
    grid-template-columns: 1fr;
  }

  .mast-row {
    flex-direction: column;
    align-items: flex-start;
  }

  .menu {
    justify-content: flex-start;
  }

  .lead h1 {
    font-size: 26px;
  }

  .ladder li {
    grid-template-columns: 56px 1fr;
  }
}