:root {
  --bg: #0b0f19;
  --surface: #121826;
  --surface-2: #192234;
  --border: #263147;
  --text: #f1f5f9;
  --muted: #94a3b8;
  --accent: #3b82f6;
  --accent-hover: #2563eb;
  --green: #10b981;
  --amber: #f59e0b;
  --red: #ef4444;
  --radius: 12px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.55;
}

.container {
  max-width: 1040px;
  margin: 0 auto;
  padding: 0 20px;
}

header {
  border-bottom: 1px solid var(--border);
  background: rgba(11, 15, 25, 0.9);
  backdrop-filter: blur(8px);
  position: sticky;
  top: 0;
  z-index: 20;
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.brand {
  font-weight: 800;
  font-size: 1.15rem;
  letter-spacing: -0.02em;
  display: flex;
  align-items: center;
  gap: 8px;
}

.brand-dot {
  width: 10px;
  height: 10px;
  border-radius: 999px;
  background: var(--green);
  box-shadow: 0 0 12px var(--green);
}

.nav-links {
  display: flex;
  gap: 20px;
  font-size: 0.9rem;
}

.nav-links a {
  color: var(--muted);
  text-decoration: none;
}

.nav-links a:hover {
  color: var(--text);
}

.hero {
  padding: 56px 0 32px;
  text-align: center;
}

.pill {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(59, 130, 246, 0.14);
  border: 1px solid rgba(59, 130, 246, 0.35);
  color: #93c5fd;
  font-size: 0.8rem;
  font-weight: 600;
  margin-bottom: 14px;
}

h1 {
  font-size: clamp(1.9rem, 4vw, 2.8rem);
  line-height: 1.15;
  margin: 0 0 14px;
  letter-spacing: -0.03em;
}

.hero p {
  max-width: 660px;
  margin: 0 auto;
  color: var(--muted);
  font-size: 1.05rem;
}

.tabs {
  display: flex;
  gap: 10px;
  justify-content: center;
  margin: 28px 0 20px;
  flex-wrap: wrap;
}

.tab-btn {
  background: var(--surface);
  color: var(--muted);
  border: 1px solid var(--border);
  padding: 10px 18px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 0.92rem;
  cursor: pointer;
  transition: all 0.15s ease;
}

.tab-btn:hover {
  color: var(--text);
  border-color: #3b4b6b;
}

.tab-btn.active {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin-bottom: 24px;
}

.tool-panel {
  display: none;
}

.tool-panel.active {
  display: block;
}

.input-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

input[type="text"],
input[type="email"],
input[type="number"],
textarea {
  width: 100%;
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 8px;
  padding: 12px 14px;
  font-size: 0.95rem;
  font-family: inherit;
}

input:focus,
textarea:focus {
  outline: none;
  border-color: var(--accent);
}

.input-row input {
  flex: 1;
  min-width: 240px;
}

.btn {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  padding: 12px 20px;
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
}

.btn:hover {
  background: var(--accent-hover);
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.btn-green {
  background: var(--green);
  color: #052e16;
}

.btn-green:hover {
  background: #059669;
  color: #fff;
}

.field {
  margin-bottom: 14px;
}

.field label {
  display: block;
  font-size: 0.85rem;
  color: var(--muted);
  margin-bottom: 6px;
  font-weight: 500;
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 14px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px;
}

.result-box {
  margin-top: 22px;
  border-top: 1px solid var(--border);
  padding-top: 20px;
}

.score-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 14px;
  margin-bottom: 16px;
}

.score-badge {
  font-size: 2rem;
  font-weight: 800;
  line-height: 1;
}

.status-pass { color: var(--green); }
.status-warn { color: var(--amber); }
.status-fail { color: var(--red); }
.status-info { color: var(--muted); }

.check-item {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 14px;
  margin-bottom: 10px;
}

.check-top {
  display: flex;
  justify-content: space-between;
  font-weight: 600;
  margin-bottom: 4px;
}

.check-detail {
  color: var(--muted);
  font-size: 0.9rem;
}

.code-snippet {
  background: var(--bg);
  border: 1px solid var(--border);
  padding: 8px 10px;
  border-radius: 6px;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.8rem;
  margin-top: 8px;
  overflow-x: auto;
  color: #cbd5e1;
}

.cta-banner {
  margin-top: 18px;
  background: linear-gradient(135deg, rgba(59, 130, 246, 0.16), rgba(16, 185, 129, 0.12));
  border: 1px solid rgba(59, 130, 246, 0.4);
  border-radius: 10px;
  padding: 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.cta-banner h3 {
  margin: 0 0 4px;
  font-size: 1.05rem;
}

.cta-banner p {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.stack-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.stack-badge {
  font-size: 0.75rem;
  font-weight: 700;
  color: #93c5fd;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 8px;
}

.stack-card h3 {
  margin: 0 0 8px;
  font-size: 1.15rem;
}

.stack-card p {
  color: var(--muted);
  font-size: 0.9rem;
  margin: 0 0 16px;
}

.stat-card {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 16px;
}

.stat-label {
  font-size: 0.82rem;
  color: var(--muted);
}

.stat-value {
  font-size: 1.55rem;
  font-weight: 800;
  margin-top: 4px;
}

.section-title {
  margin: 44px 0 16px;
  font-size: 1.45rem;
  letter-spacing: -0.02em;
}

footer {
  border-top: 1px solid var(--border);
  padding: 28px 0 40px;
  margin-top: 48px;
  color: var(--muted);
  font-size: 0.85rem;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}