:root {
  --bg: #0b0f17;
  --panel: #131a26;
  --panel-alt: #1b2434;
  --border: #2a364d;
  --accent: #38bdf8;
  --accent-glow: rgba(56, 189, 248, 0.18);
  --emerald: #34d399;
  --emerald-glow: rgba(52, 211, 153, 0.16);
  --indigo: #818cf8;
  --amber: #fbbf24;
  --danger: #f87171;
  --text: #f1f5f9;
  --muted: #94a3b8;
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --mono: 'JetBrains Mono', 'Fira Code', Consolas, monospace;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  line-height: 1.68;
  font-size: 16px;
}
a { color: var(--accent); text-decoration: none; transition: color 0.15s; }
a:hover { color: #7dd3fc; text-decoration: underline; }
.container { max-width: 1180px; margin: 0 auto; padding: 0 20px; }

.site-header {
  background: rgba(19, 26, 38, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}
.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 0;
  flex-wrap: wrap;
  gap: 12px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 1.15rem;
  color: var(--text);
  text-decoration: none !important;
}
.brand-badge {
  background: linear-gradient(135deg, #38bdf8, #818cf8);
  color: #0b0f17;
  font-weight: 900;
  padding: 4px 9px;
  border-radius: 6px;
  font-size: 0.82rem;
  font-family: var(--mono);
}
.nav-links {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}
.nav-links a {
  color: var(--muted);
  font-size: 0.88rem;
  font-weight: 600;
  padding: 6px 12px;
  border-radius: 6px;
  text-decoration: none;
}
.nav-links a:hover, .nav-links a.active {
  color: var(--text);
  background: var(--panel-alt);
}

.hero {
  padding: 36px 0 24px;
  text-align: center;
}
.version-pill {
  display: inline-block;
  background: var(--accent-glow);
  color: #7dd3fc;
  border: 1px solid rgba(56, 189, 248, 0.4);
  font-size: 0.82rem;
  font-weight: 700;
  padding: 4px 14px;
  border-radius: 999px;
  margin-bottom: 12px;
}
h1 {
  font-size: clamp(1.85rem, 3.5vw, 2.6rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 12px;
  color: #ffffff;
}
.hero-sub {
  max-width: 820px;
  margin: 0 auto 22px;
  color: var(--muted);
  font-size: 1.05rem;
}

.presets-bar {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px;
  margin-bottom: 24px;
}
.presets-title {
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--amber);
  font-weight: 700;
  margin-bottom: 10px;
}
.preset-btns {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.preset-btn {
  background: var(--panel-alt);
  color: var(--text);
  border: 1px solid var(--border);
  padding: 8px 14px;
  border-radius: 8px;
  font-size: 0.86rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s;
}
.preset-btn:hover {
  border-color: var(--accent);
  background: var(--accent-glow);
}

.calc-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 22px;
  margin-bottom: 36px;
}
@media (max-width: 920px) {
  .calc-grid { grid-template-columns: 1fr; }
}
.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 22px;
}
.card-title {
  font-size: 1.12rem;
  font-weight: 700;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  color: #fff;
}
.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-bottom: 14px;
}
@media (max-width: 580px) {
  .form-row { grid-template-columns: 1fr; }
}
label.field-label {
  display: block;
  font-size: 0.83rem;
  color: var(--muted);
  font-weight: 600;
  margin-bottom: 6px;
}
select, input[type="number"], input[type="text"], textarea {
  width: 100%;
  background: #0b0f17;
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 12px;
  font-size: 0.92rem;
  font-family: var(--mono);
}
textarea {
  min-height: 185px;
  resize: vertical;
  line-height: 1.5;
}
select:focus, input:focus, textarea:focus {
  outline: none;
  border-color: var(--accent);
}
.summary-badges {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin-bottom: 16px;
}
.stat-box {
  background: var(--panel-alt);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px;
  text-align: center;
}
.stat-label {
  font-size: 0.74rem;
  color: var(--muted);
  text-transform: uppercase;
  font-weight: 700;
}
.stat-val {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--emerald);
  font-family: var(--mono);
  margin-top: 4px;
}
.canvas-box {
  background: #080b11;
  border: 1px solid var(--border);
  border-radius: 10px;
  overflow: hidden;
  margin-bottom: 14px;
  position: relative;
}
canvas {
  display: block;
  width: 100%;
  height: 270px;
}
.code-output {
  background: #080b11;
  border: 1px solid var(--border);
  border-radius: 9px;
  padding: 14px;
  font-family: var(--mono);
  font-size: 0.83rem;
  color: #a5f3fc;
  white-space: pre-wrap;
  word-break: break-word;
  max-height: 270px;
  overflow-y: auto;
}
.action-bar {
  display: flex;
  gap: 10px;
  margin-top: 14px;
  flex-wrap: wrap;
}
.btn-action {
  flex: 1;
  background: var(--panel-alt);
  color: var(--text);
  border: 1px solid var(--border);
  padding: 10px 14px;
  border-radius: 8px;
  font-weight: 700;
  font-size: 0.86rem;
  cursor: pointer;
  transition: all 0.15s;
}
.btn-action.primary {
  background: linear-gradient(135deg, #0284c7, #4f46e5);
  border-color: #38bdf8;
  color: #ffffff;
}
.btn-action:hover {
  border-color: var(--accent);
  transform: translateY(-1px);
}

.content-section {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 28px;
  margin-bottom: 26px;
}
.content-section h2 {
  font-size: 1.5rem;
  color: #ffffff;
  margin-bottom: 14px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 10px;
}
.content-section h3 {
  font-size: 1.16rem;
  color: #7dd3fc;
  margin: 20px 0 8px;
}
.content-section p {
  margin-bottom: 14px;
  color: #cbd5e1;
}
.content-section ul, .content-section ol {
  margin: 0 0 16px 22px;
  color: #cbd5e1;
}
.content-section li { margin-bottom: 8px; }
code {
  background: #0b0f17;
  padding: 2px 6px;
  border-radius: 4px;
  font-family: var(--mono);
  font-size: 0.88em;
  color: #7dd3fc;
}

.table-wrap { overflow-x: auto; margin: 16px 0; }
table.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}
table.data-table th, table.data-table td {
  border: 1px solid var(--border);
  padding: 10px 14px;
  text-align: left;
}
table.data-table th {
  background: var(--panel-alt);
  color: #ffffff;
  font-weight: 700;
}
table.data-table tr:nth-child(even) { background: rgba(255,255,255,0.02); }

.faq-item {
  border-bottom: 1px solid var(--border);
  padding: 16px 0;
}
.faq-item:last-child { border-bottom: none; }
.faq-q {
  font-weight: 700;
  font-size: 1.05rem;
  color: #ffffff;
  margin-bottom: 6px;
}
.faq-a { color: #cbd5e1; margin: 0; }

.site-footer {
  border-top: 1px solid var(--border);
  padding: 36px 0;
  margin-top: 48px;
  color: var(--muted);
  font-size: 0.88rem;
}
.footer-grid {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 20px;
}