@charset "UTF-8";
/* ==========================================================================
   WhatsApp 网页版 · 电脑端图纸（Desktop Sheet）
   设计方向：工程图纸 / 技术制图
   深藏青底 + 图纸蓝线 + 琥珀标注 + 双线图框 + 20px 网格 + 右下标题栏
   无圆角、无阴影、无渐变装饰。
   ========================================================================== */

:root {
  --bg: #0d1f2e;
  --bg-2: #0a1926;
  --panel: #12293b;
  --panel-2: #16324a;
  --line: rgba(140, 190, 230, 0.17);
  --line-2: rgba(140, 190, 230, 0.34);
  --line-3: rgba(140, 190, 230, 0.55);
  --text: #e1ebf4;
  --text-2: #a6bccd;
  --muted: #7b91a4;
  --blue: #5aa9e6;
  --blue-dim: #2f6289;
  --blue-soft: rgba(90, 169, 230, 0.1);
  --amber: #ffc857;

  --mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, "Courier New", monospace;
  --sans: system-ui, -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;

  --fs-xxs: 0.6875rem;
  --fs-xs: 0.75rem;
  --fs-sm: 0.8125rem;
  --fs-base: 0.97rem;
  --fs-md: 1.05rem;
  --fs-lg: 1.22rem;
  --fs-h3: clamp(1rem, 1.5vw, 1.15rem);
  --fs-h2: clamp(1.35rem, 2.6vw, 1.9rem);
  --fs-hero: clamp(1.95rem, 4.4vw, 3.2rem);

  --sp-1: 0.25rem;
  --sp-2: 0.5rem;
  --sp-3: 0.75rem;
  --sp-4: 1rem;
  --sp-5: 1.5rem;
  --sp-6: 2.25rem;
  --sp-7: 3.25rem;

  --wrap: 1120px;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: var(--fs-base);
  line-height: 1.72;
  -webkit-font-smoothing: antialiased;
}

/* 图纸网格 */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(140, 190, 230, 0.045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(140, 190, 230, 0.045) 1px, transparent 1px),
    linear-gradient(rgba(140, 190, 230, 0.08) 1px, transparent 1px),
    linear-gradient(90deg, rgba(140, 190, 230, 0.08) 1px, transparent 1px);
  background-size: 20px 20px, 20px 20px, 100px 100px, 100px 100px;
}

/* ---------- 图框 ---------- */
.sheet {
  position: relative;
  z-index: 1;
  margin: clamp(8px, 1.6vw, 22px);
  border: 1px solid var(--line-3);
  min-height: calc(100vh - 2 * clamp(8px, 1.6vw, 22px));
  display: flex;
  flex-direction: column;
}
.sheet::before {
  content: "";
  position: absolute;
  inset: 5px;
  border: 1px solid var(--line);
  pointer-events: none;
  z-index: 0;
}
.corner {
  position: absolute;
  width: 13px;
  height: 13px;
  z-index: 2;
  pointer-events: none;
}
.corner::before,
.corner::after {
  content: "";
  position: absolute;
  background: var(--blue);
}
.corner::before { left: 0; top: 6px; width: 13px; height: 1px; }
.corner::after { left: 6px; top: 0; width: 1px; height: 13px; }
.c-tl { left: -7px; top: -7px; }
.c-tr { right: -7px; top: -7px; }
.c-bl { left: -7px; bottom: -7px; }
.c-br { right: -7px; bottom: -7px; }

.inner {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  flex: 1;
}

.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: clamp(1rem, 3.4vw, 2.4rem);
}

/* ---------- 顶栏 ---------- */
.topbar {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding-block: 0.7rem;
  border-bottom: 1px solid var(--line);
  font-family: var(--mono);
  font-size: var(--fs-xxs);
  letter-spacing: 0.12em;
  color: var(--muted);
}
.topbar b { color: var(--text); font-weight: 600; }
.topbar .sep { color: var(--line-3); }
.topbar .right { margin-left: auto; display: flex; gap: 1.1rem; white-space: nowrap; }

/* ---------- 导航 ---------- */
.nav { border-bottom: 1px solid var(--line-2); background: rgba(10, 25, 38, 0.6); }
.nav-in {
  display: flex;
  align-items: stretch;
  gap: clamp(0.6rem, 2vw, 1.6rem);
  min-height: 50px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin-right: 0.4rem;
  padding-right: 1rem;
  border-right: 1px solid var(--line);
  flex: none;
  text-decoration: none;
  color: var(--text);
}
.brand-mark {
  width: 28px;
  height: 28px;
  display: grid;
  place-items: center;
  border: 1px solid var(--blue-dim);
  color: var(--blue);
  font-family: var(--mono);
  font-size: 0.6rem;
  letter-spacing: -0.04em;
}
.brand-text {
  font-family: var(--mono);
  font-size: var(--fs-xxs);
  letter-spacing: 0.14em;
  line-height: 1.3;
  color: var(--text-2);
}
.brand-text span { display: block; color: var(--muted); font-size: 0.62rem; }

.nav-links { display: flex; align-items: stretch; gap: clamp(0.45rem, 1.5vw, 1.2rem); overflow-x: auto; margin-right: auto; }
.nav-links a {
  display: flex;
  align-items: center;
  padding-block: 0.8rem;
  color: var(--text-2);
  font-size: var(--fs-sm);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  white-space: nowrap;
}
.nav-links a:hover { color: var(--text); border-bottom-color: var(--line-2); }
.nav-links a[aria-current="page"] { color: var(--blue); border-bottom-color: var(--blue); }

.nav-cta {
  display: none;
  align-items: center;
  padding-inline: 0.8rem;
  margin-block: 0.65rem;
  border: 1px solid var(--blue-dim);
  color: var(--blue);
  font-family: var(--mono);
  font-size: var(--fs-xxs);
  letter-spacing: 0.1em;
  text-decoration: none;
  white-space: nowrap;
}
.nav-cta:hover { background: var(--blue-soft); }

/* ---------- 首屏 ---------- */
.hero { padding-block: clamp(2rem, 4.5vw, 3.6rem) clamp(1.6rem, 3vw, 2.4rem); }
.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--mono);
  font-size: var(--fs-xxs);
  letter-spacing: 0.18em;
  color: var(--blue);
  margin-bottom: 1rem;
}
.hero-tag::before { content: ""; width: 20px; height: 1px; background: var(--blue); }
.hero h1 {
  margin: 0;
  font-size: var(--fs-hero);
  line-height: 1.14;
  letter-spacing: -0.02em;
  font-weight: 800;
  text-wrap: balance;
  max-width: 22em;
}
.hero h1 em { font-style: normal; color: var(--amber); }
.hero-lead {
  margin: 1.2rem 0 0;
  max-width: 44em;
  color: var(--text-2);
  font-size: var(--fs-md);
  line-height: 1.85;
}
.hero-acts { display: flex; flex-wrap: wrap; gap: 0.6rem; margin-top: 1.7rem; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.62rem 1.1rem;
  border: 1px solid var(--line-2);
  color: var(--text);
  font-family: var(--mono);
  font-size: var(--fs-xs);
  letter-spacing: 0.05em;
  text-decoration: none;
}
.btn:hover { border-color: var(--blue); color: var(--blue); }
.btn-solid { background: var(--blue); border-color: var(--blue); color: #081722; font-weight: 600; }
.btn-solid:hover { background: #7cc0f0; color: #081722; }

/* ---------- 三种形态对照 ---------- */
.forms {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}
.form-card {
  background: var(--panel);
  padding: clamp(0.9rem, 2vw, 1.3rem);
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}
.form-card .code {
  font-family: var(--mono);
  font-size: var(--fs-xxs);
  letter-spacing: 0.14em;
  color: var(--muted);
}
.form-card h3 { margin: 0; font-size: var(--fs-md); font-weight: 700; }
.form-card p { margin: 0; font-size: var(--fs-sm); color: var(--text-2); }
.form-card .pick {
  margin-top: auto;
  padding-top: 0.6rem;
  border-top: 1px dashed var(--line);
  font-family: var(--mono);
  font-size: var(--fs-xxs);
  color: var(--blue);
  letter-spacing: 0.06em;
}
.form-card.is-best { box-shadow: inset 0 2px 0 var(--amber); }
.form-card.is-best h3 { color: var(--amber); }

/* ---------- 章节 ---------- */
.sec { padding-block: clamp(2rem, 4vw, 3.2rem); border-top: 1px solid var(--line); }
.sec-head { margin-bottom: clamp(1.2rem, 2.4vw, 2rem); }
.sec-no {
  display: block;
  font-family: var(--mono);
  font-size: var(--fs-xxs);
  letter-spacing: 0.2em;
  color: var(--blue);
  margin-bottom: 0.55rem;
}
.sec-title {
  margin: 0;
  font-size: var(--fs-h2);
  letter-spacing: -0.015em;
  line-height: 1.2;
  text-wrap: balance;
}
.sec-sub { margin: 0.7rem 0 0; max-width: 46em; color: var(--text-2); font-size: var(--fs-sm); }

/* ---------- 规格表 / 键值 ---------- */
.kv { border-top: 1px solid var(--line); }
.kv > div {
  display: grid;
  grid-template-columns: 11rem minmax(0, 1fr);
  gap: 1rem;
  padding: 0.7rem 0;
  border-bottom: 1px solid var(--line);
}
.kv dt {
  font-family: var(--mono);
  font-size: var(--fs-xxs);
  letter-spacing: 0.1em;
  color: var(--muted);
  padding-top: 0.15rem;
}
.kv dd { margin: 0; font-size: var(--fs-sm); color: var(--text-2); }
.kv dd b { color: var(--text); }

/* ---------- 表格 ---------- */
.tbl-wrap { overflow-x: auto; max-width: 100%; border: 1px solid var(--line); background: var(--panel); }
.tbl { width: 100%; min-width: 36rem; border-collapse: collapse; font-size: var(--fs-sm); text-align: left; }
.tbl th {
  padding: 0.6rem 0.8rem;
  background: var(--panel-2);
  border-bottom: 1px solid var(--line-2);
  font-family: var(--mono);
  font-size: var(--fs-xxs);
  font-weight: 600;
  letter-spacing: 0.1em;
  color: var(--text-2);
  white-space: nowrap;
}
.tbl td {
  padding: 0.62rem 0.8rem;
  border-bottom: 1px solid var(--line);
  color: var(--text-2);
  vertical-align: top;
}
.tbl tr:last-child td { border-bottom: 0; }
.tbl td b, .tbl td strong { color: var(--text); }
.tbl .rn { width: 2.8rem; font-family: var(--mono); font-size: var(--fs-xxs); color: var(--muted); }

/* ---------- 提示 ---------- */
.note {
  border: 1px solid var(--line);
  border-left: 3px solid var(--amber);
  background: var(--panel);
  padding: 0.9rem 1rem;
  margin-block: 1.6rem;
}
.note b {
  display: block;
  font-family: var(--mono);
  font-size: var(--fs-xxs);
  letter-spacing: 0.14em;
  color: var(--amber);
  margin-bottom: 0.35rem;
}
.note p { font-size: var(--fs-sm); color: var(--text-2); }
.note p + p { margin-top: 0.55rem; }

/* ---------- 步骤 ---------- */
.steps { border-top: 1px solid var(--line); }
.step {
  display: grid;
  grid-template-columns: 4.4rem minmax(0, 1fr);
  gap: clamp(0.7rem, 2vw, 1.5rem);
  padding-block: clamp(1rem, 1.9vw, 1.5rem);
  border-bottom: 1px solid var(--line);
}
.step-no { font-family: var(--mono); font-size: var(--fs-xxs); letter-spacing: 0.1em; color: var(--blue); padding-top: 0.2rem; }
.step h3 { margin: 0 0 0.35rem; font-size: var(--fs-h3); }
.step p { margin: 0; font-size: var(--fs-sm); color: var(--text-2); max-width: 48em; }
.step p + p { margin-top: 0.5rem; }

/* ---------- 面板 ---------- */
.grid-2 { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1px; background: var(--line); border: 1px solid var(--line); }
.panel { background: var(--panel); padding: clamp(0.9rem, 2vw, 1.2rem); }
.panel h3 { margin: 0 0 0.45rem; font-size: var(--fs-md); }
.panel p { margin: 0; font-size: var(--fs-sm); color: var(--text-2); }
.panel p + p { margin-top: 0.55rem; }
.panel .tag { display: inline-block; font-family: var(--mono); font-size: var(--fs-xxs); letter-spacing: 0.1em; color: var(--amber); margin-bottom: 0.4rem; }

/* ---------- 问答 ---------- */
.qa { border-top: 1px solid var(--line); }
.qa details { border-bottom: 1px solid var(--line); }
.qa summary {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
  padding: 0.9rem 0;
  cursor: pointer;
  list-style: none;
  color: var(--text);
}
.qa summary::-webkit-details-marker { display: none; }
.qa summary::after { content: "+"; font-family: var(--mono); color: var(--blue); flex: none; }
.qa details[open] summary::after { content: "−"; }
.ans { padding: 0 0 1rem; font-size: var(--fs-sm); color: var(--text-2); }
.ans p + p { margin-top: 0.6rem; }

/* ---------- 相关 ---------- */
.related { margin-top: clamp(1.6rem, 3vw, 2.4rem); }
.related h2 {
  font-family: var(--mono);
  font-size: var(--fs-xxs);
  letter-spacing: 0.18em;
  color: var(--muted);
  margin: 0 0 0.7rem;
  font-weight: 600;
}
.related ul { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 1px; background: var(--line); border: 1px solid var(--line); }
.related a {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 0.7rem;
  padding: 0.8rem 0.9rem;
  background: var(--panel);
  color: var(--text-2);
  font-size: var(--fs-sm);
  text-decoration: none;
  line-height: 1.5;
}
.related a:hover { background: var(--panel-2); color: var(--blue); }
.related a i { font-family: var(--mono); font-style: normal; font-size: var(--fs-xxs); color: var(--muted); flex: none; }

/* ---------- 页面头 ---------- */
.page-head { padding-block: 1rem 0; }
.crumb { font-family: var(--mono); font-size: var(--fs-xxs); letter-spacing: 0.08em; color: var(--muted); padding-block: 0.9rem; }
.crumb ol { display: flex; flex-wrap: wrap; gap: 0.45rem; margin: 0; padding: 0; list-style: none; }
.crumb li + li::before { content: "›"; margin-right: 0.45rem; color: var(--line-3); }
.crumb a { color: var(--muted); text-decoration: none; }
.crumb a:hover { color: var(--blue); }
.crumb [aria-current] { color: var(--text-2); }

.page-head h1 { margin: 0; font-size: clamp(1.7rem, 3.6vw, 2.5rem); line-height: 1.16; letter-spacing: -0.02em; text-wrap: balance; }
.page-head .lead { margin: 0.9rem 0 0; max-width: 44em; color: var(--text-2); }
.meta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 1.3rem;
  margin-top: 1.2rem;
  padding-top: 0.8rem;
  border-top: 1px solid var(--line);
  font-family: var(--mono);
  font-size: var(--fs-xxs);
  letter-spacing: 0.08em;
  color: var(--muted);
}

/* ---------- 图纸标题栏 ---------- */
.stamp {
  margin-top: auto;
  border-top: 1px solid var(--line-2);
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  font-family: var(--mono);
  font-size: var(--fs-xxs);
  letter-spacing: 0.08em;
}
.stamp > div {
  padding: 0.55rem 0.9rem;
  border-left: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}
.stamp > div:first-child { border-left: 0; }
.stamp b { color: var(--muted); font-weight: 400; font-size: 0.62rem; letter-spacing: 0.14em; }
.stamp span { color: var(--text-2); }

/* ---------- 页脚 ---------- */
.foot { border-top: 1px solid var(--line-2); }
.foot-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr;
  gap: clamp(1.2rem, 3vw, 2.4rem);
  padding-block: clamp(1.5rem, 3vw, 2.2rem);
}
.foot h2 {
  font-family: var(--mono);
  font-size: var(--fs-xxs);
  letter-spacing: 0.16em;
  color: var(--muted);
  margin: 0 0 0.7rem;
  font-weight: 600;
}
.foot p { margin: 0; font-size: var(--fs-sm); color: var(--text-2); max-width: 24em; }
.foot ul { margin: 0; padding: 0; list-style: none; }
.foot li + li { margin-top: 0.35rem; }
.foot li a { font-size: var(--fs-sm); color: var(--text-2); text-decoration: none; }
.foot li a:hover { color: var(--blue); }
.foot-meta {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.5rem;
  border-top: 1px solid var(--line);
  padding-block: 0.8rem;
  font-family: var(--mono);
  font-size: var(--fs-xxs);
  letter-spacing: 0.06em;
  color: var(--muted);
}

/* ---------- 404 ---------- */
.err { min-height: 54vh; display: grid; grid-template-columns: minmax(0, 1fr); place-items: center; text-align: center; padding-block: 2.2rem; }
.err-code { font-family: var(--mono); font-size: clamp(3rem, 12vw, 6rem); letter-spacing: -0.04em; color: var(--blue); line-height: 1; }
.err h1 { margin: 1rem 0 0; font-size: var(--fs-h2); }
.err .lead { margin: 0.7rem 0 0; color: var(--text-2); max-width: 32em; }
.err .hero-acts { justify-content: center; }

/* ---------- 工具 ---------- */
.mono { font-family: var(--mono); }
.dim { color: var(--muted); }
.mt-5 { margin-top: 1.5rem; }

/* ---------- 响应式 ---------- */
@media (min-width: 920px) { .nav-cta { display: inline-flex; } }

@media (max-width: 919px) {
  .forms { grid-template-columns: minmax(0, 1fr); }
  .grid-2 { grid-template-columns: minmax(0, 1fr); }
  .foot-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .related ul { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .stamp { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .stamp > div:nth-child(3) { border-left: 0; border-top: 1px solid var(--line); }
  .stamp > div:nth-child(4) { border-top: 1px solid var(--line); }
  .topbar .right span:first-child { display: none; }
}

@media (max-width: 700px) {
  .kv > div { grid-template-columns: minmax(0, 1fr); gap: 0.2rem; }
  .step { grid-template-columns: minmax(0, 1fr); gap: 0.3rem; }
  .related ul { grid-template-columns: minmax(0, 1fr); }
  .foot-grid { grid-template-columns: minmax(0, 1fr); }
  .brand { border-right: 0; padding-right: 0; }
  .topbar { font-size: 0.6rem; }
  .sheet { margin: 6px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { animation: none !important; transition: none !important; }
}