:root {
  --bg: #0d1117;
  --bg-soft: #161c26;
  --card: #1a2230;
  --card-edge: #2a3547;
  --text: #e6edf3;
  --text-dim: #8b98a9;
  --accent: #4cc2ff;
  --accent-2: #7ee787;
  --warn: #f0b429;
  --err: #ff6b6b;
  font-size: 16px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  background-image:
    radial-gradient(ellipse 900px 420px at 70% -10%, rgba(76, 194, 255, 0.10), transparent),
    radial-gradient(ellipse 700px 380px at 10% 110%, rgba(126, 231, 135, 0.05), transparent);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.wrap { max-width: 1000px; margin: 0 auto; padding: 0 20px; width: 100%; }

/* ---------- header ---------- */
.site-header {
  border-bottom: 1px solid var(--card-edge);
  background: rgba(13, 17, 23, 0.85);
  backdrop-filter: blur(8px);
  position: sticky; top: 0; z-index: 10;
}
.header-inner { display: flex; align-items: center; gap: 18px; padding-top: 12px; padding-bottom: 12px; }
.brand { display: flex; align-items: center; gap: 12px; text-decoration: none; flex-shrink: 0; }
.logo { width: 40px; height: 40px; color: var(--accent); }
.brand h1 { font-size: 1.25rem; letter-spacing: 2px; color: var(--text); }
.brand .domain { font-size: 0.78rem; color: var(--accent); letter-spacing: 1px; }

/* ---------- 主导航 ---------- */
.main-nav { display: flex; align-items: center; gap: 2px; flex: 1; }
.nav-group { position: relative; }
.nav-cat {
  background: transparent; border: 0; color: var(--text-dim);
  font-size: 0.9rem; padding: 8px 14px; border-radius: 8px; cursor: pointer;
  transition: color .15s, background .15s;
}
.nav-cat:hover { color: var(--text); background: var(--bg-soft); }
.nav-cat .caret { font-size: 0.7rem; margin-left: 4px; opacity: 0.7; }
.nav-group.open .nav-cat { color: var(--accent); background: var(--bg-soft); }
.nav-dropdown {
  display: none; position: absolute; top: calc(100% + 6px); left: 0; z-index: 30;
  min-width: 230px; background: var(--card); border: 1px solid var(--card-edge);
  border-radius: 10px; padding: 6px; box-shadow: 0 10px 30px rgba(0,0,0,0.45);
}
.nav-group.open .nav-dropdown { display: block; }
.nav-item {
  display: block; padding: 8px 12px; border-radius: 7px; text-decoration: none;
}
.nav-item:hover { background: var(--bg-soft); }
.nav-item .nav-item-name { display: block; color: var(--text); font-size: 0.9rem; }
.nav-item:hover .nav-item-name { color: var(--accent); }
.nav-item .nav-item-sub { display: block; color: var(--text-dim); font-size: 0.75rem; }
.nav-item.planned { cursor: default; }
.nav-item.planned .nav-item-name { color: var(--text-dim); display: inline; }
.nav-item .badge {
  font-size: 0.68rem; color: var(--text-dim); border: 1px solid var(--card-edge);
  border-radius: 5px; padding: 1px 6px; margin-left: 6px; vertical-align: 1px;
}
.nav-link {
  color: var(--text-dim); font-size: 0.9rem; text-decoration: none;
  padding: 8px 14px; border-radius: 8px; transition: color .15s, background .15s;
}
.nav-link:hover { color: var(--text); background: var(--bg-soft); }
.nav-search { margin-left: auto; }
.nav-search input {
  background: var(--bg-soft); border: 1px solid var(--card-edge); border-radius: 8px;
  color: var(--text); padding: 7px 12px; font-size: 0.85rem; width: 150px;
  outline: none; transition: border-color .15s, width .2s;
}
.nav-search input:focus { border-color: var(--accent); width: 190px; }
.nav-burger {
  display: none; background: transparent; border: 1px solid var(--card-edge);
  border-radius: 8px; color: var(--text); font-size: 1.1rem; padding: 4px 12px;
  cursor: pointer; margin-left: auto;
}

/* ---------- 门户 / 全部工具 ---------- */
.portal-section { margin-bottom: 28px; }
.cat-title {
  font-size: 1rem; color: var(--text); font-weight: 600;
  padding-left: 10px; border-left: 3px solid var(--accent); margin-bottom: 12px;
}
.tool-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 14px; }
.tool-card {
  display: block; background: var(--card); border: 1px solid var(--card-edge);
  border-radius: 12px; padding: 16px 18px; text-decoration: none;
  transition: border-color .15s, transform .1s;
}
a.tool-card:hover { border-color: var(--accent); transform: translateY(-2px); }
.tool-card .tool-name { color: var(--text); font-size: 0.98rem; font-weight: 600; }
a.tool-card:hover .tool-name { color: var(--accent); }
.tool-card .tool-sub { color: var(--accent-2); font-size: 0.78rem; margin-top: 2px; }
.tool-card .tool-desc { color: var(--text-dim); font-size: 0.8rem; margin-top: 8px; }
.tool-card.planned { border-style: dashed; }
.tool-card.planned .tool-name, .tool-card.planned .tool-sub { color: var(--text-dim); }
.tool-filter {
  margin-top: 16px; width: 100%; max-width: 420px;
  background: var(--bg-soft); border: 1px solid var(--card-edge); border-radius: 10px;
  color: var(--text); padding: 11px 16px; font-size: 0.95rem; outline: none;
}
.tool-filter:focus { border-color: var(--accent); }
.no-match { color: var(--text-dim); margin-bottom: 40px; }

.hero a { color: var(--accent); }

/* ---------- hero ---------- */
.hero { padding: 42px 0 26px; }
.hero h2 {
  font-size: 1.9rem;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text; background-clip: text; color: transparent;
  margin-bottom: 10px;
}
.hero p { color: var(--text-dim); max-width: 720px; }

/* ---------- card ---------- */
.card {
  background: var(--card);
  border: 1px solid var(--card-edge);
  border-radius: 14px;
  padding: 26px 28px;
  margin-bottom: 26px;
}

/* ---------- mode tabs ---------- */
.mode-select { display: flex; align-items: center; gap: 16px; flex-wrap: wrap; }
.mode-label { color: var(--text-dim); font-size: 0.9rem; }
.mode-tabs { display: inline-flex; background: var(--bg-soft); border: 1px solid var(--card-edge); border-radius: 10px; padding: 4px; gap: 4px; }
.mode-tab {
  border: 0; background: transparent; color: var(--text-dim);
  padding: 8px 22px; border-radius: 7px; font-size: 0.95rem; cursor: pointer;
  transition: all .15s;
}
.mode-tab.active { background: var(--accent); color: #06202e; font-weight: 600; }
.mode-hint { color: var(--text-dim); font-size: 0.85rem; margin: 14px 0 4px; }

/* ---------- form ---------- */
.group-title { font-size: 1.02rem; margin: 20px 0 12px; color: var(--accent); font-weight: 600; }
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(210px, 1fr)); gap: 14px 18px; }
.grid label { font-size: 0.85rem; color: var(--text-dim); display: block; }
.field { display: flex; align-items: stretch; margin-top: 6px; }
.field input {
  flex: 1; min-width: 0;
  background: var(--bg-soft); border: 1px solid var(--card-edge);
  border-radius: 8px 0 0 8px; border-right: 0;
  color: var(--text); padding: 9px 12px; font-size: 0.98rem;
  outline: none; transition: border-color .15s;
}
.field input:focus { border-color: var(--accent); }
.field .unit {
  display: flex; align-items: center; padding: 0 10px;
  background: #232d3f; border: 1px solid var(--card-edge); border-left: 0;
  border-radius: 0 8px 8px 0; color: var(--text-dim); font-size: 0.8rem; white-space: nowrap;
}
.optional { margin-top: 18px; border: 1px dashed var(--card-edge); border-radius: 10px; padding: 12px 16px; }
.optional summary { cursor: pointer; color: var(--text-dim); font-size: 0.9rem; user-select: none; }
.optional[open] summary { color: var(--accent); margin-bottom: 12px; }
.tip { font-size: 0.78rem; color: var(--text-dim); margin-top: 10px; }

.actions { margin-top: 24px; display: flex; align-items: center; gap: 16px; flex-wrap: wrap; }
.btn-calc {
  background: linear-gradient(90deg, var(--accent), #2ea0e0);
  color: #06202e; font-weight: 700; font-size: 1rem;
  border: 0; border-radius: 10px; padding: 12px 42px; cursor: pointer;
  transition: transform .1s, box-shadow .15s;
}
.btn-calc:hover { box-shadow: 0 4px 18px rgba(76, 194, 255, 0.35); transform: translateY(-1px); }
.btn-calc:disabled { opacity: 0.6; cursor: wait; transform: none; }
.error-msg { color: var(--err); font-size: 0.9rem; }

/* ---------- results ---------- */
.results .result-mode { color: var(--text-dim); font-weight: 400; font-size: 0.85rem; margin-left: 8px; }
.warning {
  background: rgba(240, 180, 41, 0.1); border: 1px solid rgba(240, 180, 41, 0.4);
  color: var(--warn); border-radius: 8px; padding: 10px 14px; font-size: 0.88rem; margin-bottom: 16px;
}
.result-section-title {
  color: var(--text); font-size: 0.95rem; font-weight: 600;
  margin: 22px 0 10px; padding-left: 10px;
  border-left: 3px solid var(--accent);
}
.result-section-title:first-child { margin-top: 4px; }
.result-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(225px, 1fr)); gap: 12px; }
.r-item {
  background: var(--bg-soft); border: 1px solid var(--card-edge);
  border-radius: 10px; padding: 12px 16px;
}
.r-item .r-name { font-size: 0.78rem; color: var(--text-dim); }
.r-item .r-value { font-size: 1.25rem; font-weight: 700; color: var(--accent-2); font-variant-numeric: tabular-nums; }
.r-item .r-value .r-unit { font-size: 0.78rem; color: var(--text-dim); font-weight: 400; margin-left: 4px; }
.r-item.highlight { border-color: rgba(76, 194, 255, 0.5); }
.r-item.highlight .r-value { color: var(--accent); }

/* ---------- knowledge ---------- */
.knowledge { margin-bottom: 40px; }
.knowledge h3 { font-size: 1.05rem; margin-bottom: 14px; color: var(--text-dim); font-weight: 600; }
.k-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 14px; }
.k-card { background: var(--card); border: 1px solid var(--card-edge); border-radius: 12px; padding: 16px 18px; }
.k-card h4 { color: var(--accent); font-size: 0.92rem; margin-bottom: 6px; }
.k-card p { font-size: 0.82rem; color: var(--text-dim); }

/* ---------- footer ---------- */
.site-footer { border-top: 1px solid var(--card-edge); padding: 18px 0; margin-top: auto; }
.site-footer p { color: var(--text-dim); font-size: 0.78rem; text-align: center; }
.site-footer .icp { margin-top: 4px; }
.site-footer .icp a { color: var(--text-dim); text-decoration: none; }
.site-footer .icp a:hover { color: var(--accent); }

@media (max-width: 860px) {
  .nav-burger { display: block; }
  .main-nav {
    display: none; position: absolute; top: 100%; left: 0; right: 0; z-index: 40;
    flex-direction: column; align-items: stretch; gap: 4px;
    background: var(--card); border-bottom: 1px solid var(--card-edge);
    padding: 10px 16px 16px;
  }
  .main-nav.open { display: flex; }
  .nav-group { position: static; }
  .nav-cat { width: 100%; text-align: left; }
  .nav-dropdown {
    position: static; box-shadow: none; border: 0; background: transparent;
    padding-left: 14px; min-width: 0;
  }
  .nav-search { margin-left: 0; margin-top: 6px; }
  .nav-search input, .nav-search input:focus { width: 100%; }
}

@media (max-width: 640px) {
  .hero h2 { font-size: 1.45rem; }
  .card { padding: 20px 16px; }
}