/* Power Supply Quick Design Tools — offline, file:// safe */
:root {
  --bg: #f5f7fa;
  --panel: #ffffff;
  --ink: #1f2937;
  --muted: #64748b;
  --line: #e2e8f0;
  --accent: #1d4ed8;
  --accent-dark: #1e40af;
  --accent-soft: #eff6ff;
  --warn: #b45309;
  --warn-bg: #fffbeb;
  --ok: #047857;
  --radius: 10px;
  --shadow: 0 1px 3px rgba(15, 23, 42, 0.08);
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: "Segoe UI", "Microsoft YaHei", "PingFang SC", Arial, sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.5;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}
.container { max-width: 1080px; width: 100%; margin: 0 auto; padding: 24px 20px 40px; flex: 1; }

/* ---------- header / footer ---------- */
.site-header {
  background: #0f2a5f;
  color: #fff;
  box-shadow: var(--shadow);
}
.header-inner {
  max-width: 1080px; margin: 0 auto; padding: 10px 20px;
  display: flex; align-items: center; gap: 14px; flex-wrap: wrap;
}
.brand {
  font-weight: 700; font-size: 1.05rem; color: #fff;
  text-decoration: none; margin-right: auto; display: flex; align-items: center; gap: 8px;
}
.brand .logo {
  width: 26px; height: 26px; border-radius: 6px; background: linear-gradient(135deg, #3b82f6, #1d4ed8);
  display: inline-flex; align-items: center; justify-content: center; font-size: 14px;
}
.hbtn {
  color: #e0eaff; text-decoration: none; font-size: 0.88rem;
  border: 1px solid rgba(255,255,255,0.35); border-radius: 8px;
  padding: 6px 12px; transition: background 0.15s;
}
.hbtn:hover { background: rgba(255,255,255,0.14); }
.hbtn.lang-select {
  padding: 4px 6px;
}
.hbtn select {
  background: transparent; color: #e0eaff; border: none; font-size: 0.88rem; cursor: pointer;
}
.hbtn select option { color: #1f2937; background: #fff; }

.site-footer {
  background: #0f2a5f; color: #b9c6e4; font-size: 0.8rem; text-align: center;
  padding: 14px 20px;
}
.site-footer a { color: #dbe6ff; }

/* ---------- home ---------- */
.home-lead { color: var(--muted); margin-bottom: 20px; }
.card-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 16px;
}
.tool-card {
  display: block; background: var(--panel); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 18px; text-decoration: none; color: var(--ink);
  box-shadow: var(--shadow); transition: transform 0.12s, border-color 0.12s;
}
.tool-card:hover { transform: translateY(-2px); border-color: var(--accent); }
.tool-card h3 { margin: 0 0 6px; color: var(--accent-dark); font-size: 1.02rem; }
.tool-card p { margin: 0; color: var(--muted); font-size: 0.86rem; }

/* ---------- panels / forms ---------- */
.page-title { font-size: 1.45rem; margin: 4px 0 4px; color: var(--accent-dark); }
.page-desc { color: var(--muted); margin: 0 0 18px; font-size: 0.92rem; }
.panel {
  background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 18px 20px; margin-bottom: 18px;
}
.panel h2 { font-size: 1rem; margin: 0 0 14px; color: var(--accent-dark);
  border-bottom: 1px solid var(--line); padding-bottom: 8px; }
.form-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 12px 18px;
}
.field label { display: block; font-size: 0.8rem; color: var(--muted); margin-bottom: 3px; }
.field input, .field select {
  width: 100%; padding: 7px 9px; border: 1px solid var(--line); border-radius: 7px;
  font-size: 0.92rem; background: #fff; color: var(--ink);
}
.field input:focus, .field select:focus { outline: 2px solid var(--accent-soft); border-color: var(--accent); }
.field input.invalid { border-color: #dc2626; background: #fef2f2; }
.btn-row { margin-top: 16px; display: flex; gap: 10px; flex-wrap: wrap; }
.btn {
  padding: 8px 20px; border-radius: 8px; border: 1px solid var(--line);
  background: #fff; color: var(--ink); font-size: 0.92rem; cursor: pointer;
}
.btn:hover { border-color: var(--accent); }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn.primary:hover { background: var(--accent-dark); }

/* ---------- results ---------- */
.res-table { width: 100%; border-collapse: collapse; font-size: 0.9rem; }
.res-table td { padding: 7px 8px; border-bottom: 1px solid var(--line); }
.res-table tr:last-child td { border-bottom: none; }
.res-table td.lbl { color: var(--muted); width: 55%; }
.res-table td.val { font-weight: 600; font-variant-numeric: tabular-nums; text-align: right; }
.res-table tr.warn-row td { background: var(--warn-bg); color: var(--warn); }
.res-table tr.head-row td {
  background: var(--accent-soft); color: var(--accent-dark); font-weight: 700; font-size: 0.84rem;
}
.notes-text { white-space: pre-line; color: var(--muted); font-size: 0.86rem; margin: 0; }
.copied-msg { color: var(--ok); font-size: 0.84rem; margin-left: 10px; align-self: center; }

/* ---------- presets row ---------- */
.preset-row {
  margin-top: 14px; display: flex; align-items: center; gap: 8px; flex-wrap: wrap;
  border-top: 1px dashed var(--line); padding-top: 12px;
}
.preset-label { font-size: 0.8rem; color: var(--muted); }
.preset-sel {
  padding: 5px 8px; border: 1px solid var(--line); border-radius: 7px;
  font-size: 0.85rem; background: #fff; color: var(--ink); max-width: 220px;
}
.btn.btn-sm { padding: 5px 12px; font-size: 0.82rem; }
.export-row { margin-top: 14px; border-top: 1px dashed var(--line); padding-top: 12px; }

/* ---------- schematic ---------- */
.sch-wrap { text-align: center; }
.sch-wrap svg { max-width: 100%; height: auto; }

/* ---------- dark theme ---------- */
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b1220;
    --panel: #111a2c;
    --ink: #e5e7eb;
    --muted: #94a3b8;
    --line: #263450;
    --accent: #3b82f6;
    --accent-dark: #93c5fd;
    --accent-soft: #1a2740;
    --warn: #fbbf24;
    --warn-bg: #332a12;
    --shadow: none;
  }
  body { background: var(--bg); }
  .site-header, .site-footer { background: #0a1730; }
  .site-footer a { color: #9db8f0; }
  .field input, .field select, .preset-sel {
    background: #0d1729; color: var(--ink); border-color: var(--line);
  }
  .field input.invalid { border-color: #f87171; background: #2a1414; }
  .btn { background: #111a2c; color: var(--ink); border-color: var(--line); }
  .btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
  .btn.primary:hover { background: #2563eb; }
  .hbtn select option { color: #e5e7eb; background: #111a2c; }
  .res-table tr.head-row td { background: var(--accent-soft); color: var(--accent-dark); }
}

/* ---------- print: clean calculation sheet ---------- */
@media print {
  .site-header, .site-footer, .btn-row, .preset-row,
  #psut-schematic, #psut-plot, .copied-msg { display: none !important; }
  .panel { box-shadow: none; border: 1px solid #ccc; break-inside: avoid; }
  #psut-results-panel { display: block !important; }
  body { background: #fff; color: #000; }
  .page-title { font-size: 18pt; }
}