:root {
  --bg: #f8fafc;
  --card: #ffffff;
  --text: #111827;
  --muted: #6b7280;
  --accent: #2563eb;
  --border: #e5e7eb;
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
  background: var(--bg);
  color: var(--text);
}

.site-header {
  padding: 24px 16px 0;
  text-align: center;
}
.site-header h1 { margin: 0; font-weight: 700; }
.site-header .sub { margin: 6px 0 16px; color: var(--muted); }

.container {
  width: 100%;
  max-width: 980px;
  margin: 0 auto;
  padding: 16px;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px;
  margin-bottom: 16px;
  box-shadow: 0 6px 14px rgba(17, 24, 39, 0.08);
}

h2, h3 { margin: 8px 0 12px; }

.grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}
@media (max-width: 860px) { .grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 560px) { .grid { grid-template-columns: 1fr; } }

.field { display: flex; flex-direction: column; gap: 6px; }
.field label { color: var(--muted); font-size: 14px; }
.field input, .field select {
  background: #ffffff;
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 12px;
}
.field input:focus, .field select:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.advanced { margin-top: 8px; }
.advanced > summary {
  cursor: pointer;
  padding: 8px 10px;
  border-radius: 8px;
  background: #f3f4f6;
  border: 1px solid var(--border);
}
.advanced[open] > summary { background: #e5e7eb; }
.advanced .grid { margin-top: 12px; }

.actions { display: flex; gap: 10px; margin-top: 12px; }
.btn {
  appearance: none;
  border: 1px solid var(--border);
  background: #ffffff;
  color: var(--text);
  border-radius: 10px;
  padding: 10px 14px;
  cursor: pointer;
}
.btn.primary { border-color: var(--accent); background: #eff6ff; color: var(--text); }
.btn:hover { filter: brightness(1.06); }

.result .summary-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
}
@media (max-width: 640px) { .result .summary-grid { grid-template-columns: 1fr; } }
.summary-item {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px 12px;
  background: #ffffff;
}
.summary-item .label { color: var(--muted); font-size: 13px; }
.summary-item .value { font-size: 18px; font-weight: 600; }

.breakdown { width: 100%; border-collapse: collapse; margin-top: 8px; }
.breakdown td { border-bottom: 1px solid var(--border); padding: 8px 4px; }
.breakdown tr td:last-child { text-align: right; }

.meta { color: var(--muted); margin-top: 6px; }

.site-footer { text-align: center; padding: 20px; color: var(--muted); }

/* Flash messages */
.flash-container { margin-bottom: 12px; }
.flash {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 12px;
  background: #ffffff;
  color: var(--text);
  box-shadow: 0 4px 10px rgba(17,24,39,0.06);
}
.flash.error { border-color: #fca5a5; background: #fef2f2; }
.flash.success { border-color: #86efac; background: #f0fdf4; }
.flash.warning { border-color: #fde68a; background: #fffbeb; }

/* Range (slider) styling */
.range-with-labels {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 10px;
}
.range-with-labels .desc { color: var(--muted); font-size: 13px; }
.field input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  height: 6px;
  border-radius: 6px;
  background: #e5e7eb;
  outline: none;
}
.field input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
  border: none;
}
.field input[type="range"]::-moz-range-thumb {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
  border: none;
}

/* Complexity visual image */
.complexity-visual { width: 100%; }
.complexity-visual img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
  margin: 4px 0 8px;
}

/* Dimensions section layout */
.dimensions-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 12px;
  align-items: start;
}
@media (max-width: 860px) { .dimensions-grid { grid-template-columns: 1fr; } }
.dim-fields { display: flex; flex-direction: column; gap: 12px; }
.dimensions-visual { width: 100%; }
.dimensions-visual img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
}