/* 第3套 zh · 工程蓝图（图纸白底 + 青色标注线） */
html {
  scroll-behavior: auto;
}

:root {
  --paper: #e8eef2;
  --sheet: #f5f8fa;
  --sheet-deep: #edf3f6;
  --ink: #16303c;
  --ink-soft: #3d5a68;
  --mute: #5a7582;
  --cyan: #0b7f94;
  --cyan-bright: #1294ab;
  --line: #1a8ea4;
  --line-dim: rgba(11, 127, 148, 0.28);
  --line-soft: rgba(11, 127, 148, 0.12);
  --grid: rgba(11, 127, 148, 0.11);
  --safe: #1b6f4a;
  --focus: #0b7f94;
  --mono: Consolas, "Courier New", "Microsoft YaHei", monospace;
  --sans: "Microsoft YaHei", "PingFang SC", "Noto Sans SC", sans-serif;
  --max: 1100px;
}

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

body {
  margin: 0;
  color: var(--ink);
  background-color: var(--paper);
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 22px 22px;
  font-family: var(--sans);
  font-size: 16.5px;
  line-height: 1.78;
}

img,
svg {
  max-width: 100%;
  display: inline-block;
  vertical-align: middle;
}

a {
  color: var(--cyan);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.16em;
}

a:hover {
  color: #065e6e;
}

:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
}

p {
  margin: 0 0 0.9rem;
}

h1,
h2,
h3 {
  color: var(--ink);
  line-height: 1.32;
  font-weight: 700;
}

h1 {
  font-size: clamp(1.42rem, 2.6vw, 1.95rem);
  margin: 0 0 0.85rem;
}

h2 {
  font-size: clamp(1.12rem, 2vw, 1.32rem);
  margin: 0 0 0.75rem;
}

h3 {
  font-size: 1.02rem;
  margin: 0 0 0.4rem;
  color: var(--cyan);
}

ul,
ol {
  margin: 0 0 0.95rem;
  padding-left: 1.25rem;
}

li + li {
  margin-top: 0.32rem;
}

.wrap {
  width: min(var(--max), calc(100% - 1.6rem));
  margin: 0 auto;
}

/* —— 图纸眉条，不是报头、不是侧栏 —— */
.sheet-bar {
  background: var(--sheet);
  border-bottom: 2px solid var(--line);
  box-shadow: 0 1px 0 var(--line-soft);
}

.sheet-bar__row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.8rem;
  min-height: 58px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--ink);
  text-decoration: none;
  font-weight: 700;
  letter-spacing: 0.04em;
}

.brand:hover {
  color: var(--cyan);
  text-decoration: none;
}

.brand svg {
  width: 28px;
  height: 28px;
  color: var(--cyan);
  border: 1px solid var(--line);
  padding: 3px;
  background: var(--sheet-deep);
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.15rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav a {
  display: inline-block;
  color: var(--ink);
  text-decoration: none;
  padding: 0.38rem 0.78rem;
  border: 1px solid transparent;
  font-size: 0.92rem;
}

.nav a:hover {
  color: var(--cyan);
  border-color: var(--line);
  text-decoration: none;
}

.nav a.is-on,
.nav a[aria-current="page"] {
  color: #f4fbfd;
  background: var(--cyan);
  border-color: var(--cyan);
}

.sheet-meta {
  border-top: 1px solid var(--line-dim);
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  color: var(--mute);
  padding: 0.26rem 0;
}

.sheet-meta .wrap {
  display: flex;
  justify-content: space-between;
  gap: 0.8rem;
  flex-wrap: wrap;
}

/* —— 图框：角标 + 内边距紧，禁止大留白 —— */
.frame {
  position: relative;
  background: var(--sheet);
  border: 1px solid var(--line);
  box-shadow:
    0 0 0 5px var(--paper),
    0 0 0 6px var(--line-dim);
  margin: 1.05rem 0 1.15rem;
  padding: 1.05rem 1.1rem 1.15rem;
}

.frame::before,
.frame::after,
.frame .tick-br,
.frame .tick-bl {
  content: "";
  position: absolute;
  width: 12px;
  height: 12px;
  border-color: var(--line);
  border-style: solid;
  pointer-events: none;
}

.frame::before {
  top: 5px;
  left: 5px;
  border-width: 2px 0 0 2px;
}

.frame::after {
  top: 5px;
  right: 5px;
  border-width: 2px 2px 0 0;
}

.frame .tick-bl {
  bottom: 5px;
  left: 5px;
  border-width: 0 0 2px 2px;
}

.frame .tick-br {
  bottom: 5px;
  right: 5px;
  border-width: 0 2px 2px 0;
}

.frame > h2 {
  display: flex;
  align-items: flex-start;
  gap: 0.55rem;
  padding-bottom: 0.55rem;
  margin-bottom: 0.75rem;
  border-bottom: 1px dashed var(--line);
}

.sheet-no {
  flex: 0 0 auto;
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  color: var(--cyan);
  border: 1px solid var(--line);
  padding: 0.12rem 0.36rem;
  margin-top: 0.16rem;
  background: var(--sheet-deep);
}

.kicker {
  font-family: var(--mono);
  color: var(--cyan);
  letter-spacing: 0.12em;
  font-size: 0.72rem;
  margin: 0 0 0.4rem;
}

.lede {
  font-size: 1.01rem;
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(230px, 0.72fr);
  gap: 0.95rem;
  align-items: stretch;
}

/* 印章角 / 图签 */
.stamp {
  border: 1px solid var(--line);
  background: var(--sheet-deep);
  align-self: end;
}

.stamp__cap {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.14em;
  color: var(--cyan);
  padding: 0.42rem 0.65rem;
  border-bottom: 1px solid var(--line-dim);
}

.stamp table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.86rem;
}

.stamp th,
.stamp td {
  border-top: 1px solid var(--line-dim);
  padding: 0.38rem 0.65rem;
  text-align: left;
  vertical-align: top;
}

.stamp th {
  width: 4.4rem;
  color: var(--mute);
  font-family: var(--mono);
  font-weight: 400;
  font-size: 0.72rem;
}

.stamp td {
  color: var(--ink);
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin: 0.7rem 0 0.2rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.38rem;
  padding: 0.62rem 1.05rem;
  background: var(--cyan);
  color: #f4fbfd;
  font-weight: 700;
  border: 1px solid var(--cyan);
  text-decoration: none;
}

.btn svg {
  width: 16px;
  height: 16px;
}

.btn:hover {
  background: #086d80;
  color: #fff;
  text-decoration: none;
}

.btn-ghost {
  background: transparent;
  color: var(--cyan);
  border-color: var(--line);
}

.btn-ghost:hover {
  background: rgba(11, 127, 148, 0.08);
  color: var(--ink);
}

.btn-xl {
  padding: 0.95rem 1.45rem;
  font-size: 1.12rem;
}

/* 编号条目 */
.num-list {
  list-style: none;
  margin: 0 0 0.9rem;
  padding: 0;
  counter-reset: dwg;
}

.num-list li {
  position: relative;
  padding: 0.55rem 0.7rem 0.55rem 3.1rem;
  border: 1px solid var(--line-dim);
  background: var(--sheet-deep);
  margin-bottom: 0.4rem;
}

.num-list li::before {
  counter-increment: dwg;
  content: counter(dwg, decimal-leading-zero);
  position: absolute;
  left: 0.5rem;
  top: 0.55rem;
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--cyan);
  border: 1px solid var(--line);
  padding: 0 0.28rem;
}

.cells {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.55rem;
  margin: 0.15rem 0 0.85rem;
}

.cell {
  border: 1px solid var(--line-dim);
  background: var(--sheet-deep);
  padding: 0.7rem 0.75rem 0.8rem;
}

.cell h3 {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.cell svg {
  width: 18px;
  height: 18px;
  color: var(--cyan);
  flex: 0 0 auto;
}

.plats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.5rem;
  margin: 0.2rem 0 0.85rem;
}

.plat {
  border: 1px solid var(--line-dim);
  padding: 0.7rem 0.65rem 0.8rem;
  background: var(--sheet-deep);
}

.plat strong {
  display: block;
  font-family: var(--mono);
  margin-bottom: 0.3rem;
  letter-spacing: 0.03em;
}

.quotes {
  display: grid;
  gap: 0.5rem;
  margin: 0 0 0.85rem;
}

.quote {
  display: grid;
  grid-template-columns: 7.6rem minmax(0, 1fr);
  gap: 0.7rem;
  border: 1px dashed var(--line);
  padding: 0.7rem 0.75rem;
  background: var(--sheet-deep);
}

.quote__who {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--cyan);
}

.quote__who span {
  display: block;
  color: var(--mute);
  margin-top: 0.22rem;
  font-family: var(--sans);
}

.metrics {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.45rem;
  margin: 0.2rem 0 0.85rem;
}

.metric {
  border: 1px solid var(--line);
  padding: 0.7rem 0.5rem;
  text-align: center;
  background: var(--sheet-deep);
}

.metric b {
  display: block;
  font-family: var(--mono);
  color: var(--cyan);
  font-size: 1.02rem;
  margin-bottom: 0.28rem;
}

.metric span {
  color: var(--ink-soft);
  font-size: 0.86rem;
}

.table-wrap {
  overflow-x: auto;
  margin: 0.2rem 0 0.85rem;
}

table.grid {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.94rem;
}

table.grid th,
table.grid td {
  border: 1px solid var(--line-dim);
  padding: 0.45rem 0.55rem;
  text-align: left;
  vertical-align: top;
}

table.grid th {
  background: #dce8ec;
  color: var(--cyan);
  font-family: var(--mono);
  font-weight: 400;
  font-size: 0.8rem;
}

.faq + .faq {
  border-top: 1px dashed var(--line-dim);
}

.faq {
  padding: 0.7rem 0;
}

.faq h3 {
  color: var(--ink);
}

.callout {
  border-left: 3px solid var(--line);
  padding: 0.55rem 0.75rem;
  background: var(--sheet-deep);
  margin: 0 0 0.85rem;
}

.win-panel {
  border: 2px solid var(--line);
  background: var(--sheet-deep);
  padding: 1rem 1.05rem 1.1rem;
  margin: 0 0 0.9rem;
}

.win-panel .btn-xl {
  margin-top: 0.35rem;
}

.site-foot {
  background: #d7e4e9;
  border-top: 2px solid var(--line);
  padding: 1.1rem 0 1.6rem;
  color: var(--ink-soft);
  font-size: 0.92rem;
  margin-top: 0.4rem;
}

.safe {
  color: var(--safe);
  font-weight: 700;
}

@media (max-width: 900px) {
  .hero-grid,
  .cells,
  .plats,
  .metrics,
  .quote {
    grid-template-columns: 1fr;
  }

  .sheet-bar__row {
    flex-wrap: wrap;
    padding: 0.45rem 0;
  }
}