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

:root {
  --blue: #0a66c2;
  --blue-dark: #004182;
  --blue-light: #e8f0fe;
  --text: #191919;
  --text-secondary: #666;
  --bg: #ffffff;
  --bg-alt: #f8f9fa;
  --border: #e8e8e8;
  --radius: 12px;
  --radius-sm: 8px;
}

body {
  font-family: -apple-system, system-ui, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.container {
  max-width: 640px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ── Hero ─────────────────────────────────────────────────────────────── */

.hero {
  text-align: center;
  padding: 72px 0 0;
  background: linear-gradient(180deg, var(--blue-light) 0%, var(--bg) 100%);
}

.hero-title {
  font-size: clamp(28px, 5vw, 40px);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.8px;
  margin-bottom: 12px;
}

.highlight {
  color: var(--blue);
}

.hero-desc {
  font-size: 16px;
  color: var(--text-secondary);
  max-width: 460px;
  margin: 0 auto;
  line-height: 1.5;
}

/* ── Tool ─────────────────────────────────────────────────────────────── */

.tool-section {
  padding: 32px 0 64px;
  flex: 1;
}

.tool-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.06);
}

.tool-input-wrap {
  display: flex;
  gap: 8px;
}

.tool-input {
  flex: 1;
  padding: 14px 16px;
  border: 2px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
  outline: none;
  transition: border-color 0.15s ease;
  color: var(--text);
}

.tool-input:focus {
  border-color: var(--blue);
}

.tool-input::placeholder {
  color: #aaa;
  font-family: -apple-system, system-ui, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

.tool-btn {
  padding: 14px 24px;
  background: var(--blue);
  color: #fff;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s ease;
  font-family: inherit;
  white-space: nowrap;
}

.tool-btn:hover {
  background: var(--blue-dark);
}

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

.result-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.result-item {
  padding: 12px 16px;
  background: var(--bg-alt);
  border-radius: var(--radius-sm);
}

.result-label {
  font-size: 11px;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 4px;
}

.result-value {
  font-size: 16px;
  font-weight: 600;
  color: var(--text);
}

.result-mono {
  font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
  font-size: 13px;
}

.tool-error {
  margin-top: 16px;
  padding: 12px 16px;
  background: #fef2f2;
  color: #dc2626;
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 500;
}

.how-it-works {
  margin-top: 20px;
  text-align: center;
}

.how-it-works p {
  font-size: 13px;
  color: #999;
  line-height: 1.5;
}

/* ── Footer ──────────────────────────────────────────────────────────── */

.site-footer {
  padding: 20px 0;
  text-align: center;
  border-top: 1px solid var(--border);
}

.footer-link {
  font-size: 13px;
  color: #999;
  text-decoration: none;
}

.footer-link:hover {
  color: var(--blue);
}

/* ── Responsive ──────────────────────────────────────────────────────── */

@media (max-width: 640px) {
  .hero {
    padding: 48px 0 0;
  }

  .tool-input-wrap {
    flex-direction: column;
  }

  .result-grid {
    grid-template-columns: 1fr;
  }
}