/* titrate.fyi - Design System
   Clean, authoritative, zero clutter.
   No em dashes in content. */

:root {
  --color-bg: #fafafa;
  --color-surface: #ffffff;
  --color-text: #1a1a2e;
  --color-text-secondary: #555770;
  --color-accent: #2d6a4f;
  --color-accent-light: #40916c;
  --color-accent-bg: #f0f7f4;
  --color-border: #e0e0e0;
  --color-input-bg: #f5f5f5;
  --color-result-bg: #e8f5e9;
  --color-warning: #e65100;
  --color-warning-bg: #fff3e0;
  --color-info: #1565c0;
  --color-info-bg: #e3f2fd;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;
  --max-width: 720px;
  --radius: 8px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
}

/* Dark mode */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --color-bg: #121212;
    --color-surface: #1e1e1e;
    --color-text: #e0e0e0;
    --color-text-secondary: #a0a0a0;
    --color-accent: #52b788;
    --color-accent-light: #74c69d;
    --color-accent-bg: #1a2e23;
    --color-border: #333;
    --color-input-bg: #2a2a2a;
    --color-result-bg: #1a2e23;
    --color-warning-bg: #2e1a00;
    --color-info-bg: #0a1929;
  }
}
[data-theme="dark"] {
  --color-bg: #121212;
  --color-surface: #1e1e1e;
  --color-text: #e0e0e0;
  --color-text-secondary: #a0a0a0;
  --color-accent: #52b788;
  --color-accent-light: #74c69d;
  --color-accent-bg: #1a2e23;
  --color-border: #333;
  --color-input-bg: #2a2a2a;
  --color-result-bg: #1a2e23;
  --color-warning-bg: #2e1a00;
  --color-info-bg: #0a1929;
}
[data-theme="dark"] .result-card {
  border-color: #2d4a3a;
}
[data-theme="dark"] .callout-info {
  border-left-color: #42a5f5;
}
[data-theme="dark"] .callout-warning {
  border-left-color: #ff9800;
}

/* Theme toggle */
.theme-toggle {
  background: none;
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 0.3rem 0.5rem;
  cursor: pointer;
  font-size: 1rem;
  line-height: 1;
  color: var(--color-text-secondary);
  transition: border-color 0.15s;
}
.theme-toggle:hover {
  border-color: var(--color-accent);
}

/* Breadcrumb nav */
.breadcrumb {
  font-size: 0.8rem;
  color: var(--color-text-secondary);
  margin-bottom: 0.5rem;
}
.breadcrumb a {
  color: var(--color-text-secondary);
}
.breadcrumb a:hover {
  color: var(--color-accent);
}

/* Reset */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-body);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.65;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Typography */
h1, h2, h3 { line-height: 1.25; font-weight: 600; }
h1 { font-size: 1.75rem; margin-bottom: 0.5rem; }
h2 { font-size: 1.35rem; margin-top: 2rem; margin-bottom: 0.75rem; }
h3 { font-size: 1.1rem; margin-top: 1.5rem; margin-bottom: 0.5rem; }
p { margin-bottom: 1rem; }
a { color: var(--color-accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Layout */
.site-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding: 0.75rem 1.5rem;
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-logo {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--color-text);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.site-logo span {
  color: var(--color-accent);
}

.site-nav a {
  color: var(--color-text-secondary);
  font-size: 0.875rem;
  margin-left: 1.5rem;
  font-weight: 500;
}

.site-nav a:hover {
  color: var(--color-accent);
  text-decoration: none;
}

main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2rem 1.5rem;
  width: 100%;
  flex: 1;
}

.site-footer {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2rem 1.5rem;
  width: 100%;
  border-top: 1px solid var(--color-border);
  font-size: 0.8rem;
  color: var(--color-text-secondary);
}

.site-footer a { color: var(--color-text-secondary); }

/* Page header */
.page-meta {
  font-size: 0.8rem;
  color: var(--color-text-secondary);
  margin-bottom: 0.25rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: 500;
}

.page-subtitle {
  color: var(--color-text-secondary);
  font-size: 1rem;
  margin-bottom: 2rem;
  font-weight: 400;
}

/* Calculator components */
.calc-section {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  box-shadow: var(--shadow-sm);
}

.input-group {
  margin-bottom: 1.25rem;
}

.input-group label {
  display: block;
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 0.35rem;
  color: var(--color-text);
}

.input-group .hint {
  font-size: 0.8rem;
  color: var(--color-text-secondary);
  margin-bottom: 0.35rem;
}

.input-group input[type="number"],
.input-group input[type="text"],
.input-group select {
  width: 100%;
  padding: 0.6rem 0.75rem;
  border: 1px solid var(--color-border);
  border-radius: 6px;
  font-size: 1rem;
  font-family: var(--font-body);
  background: var(--color-input-bg);
  color: var(--color-text);
  transition: border-color 0.15s;
}

.input-group input:focus,
.input-group select:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(45, 106, 79, 0.12);
}

.input-row {
  display: flex;
  gap: 1rem;
}

.input-row .input-group {
  flex: 1;
}

.radio-group {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.radio-group label {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  font-weight: 400;
  cursor: pointer;
  padding: 0.4rem 0.75rem;
  border: 1px solid var(--color-border);
  border-radius: 6px;
  font-size: 0.875rem;
  transition: all 0.15s;
}

.radio-group label:has(input:checked) {
  border-color: var(--color-accent);
  background: var(--color-accent-bg);
  color: var(--color-accent);
  font-weight: 500;
}

.radio-group input[type="radio"] {
  display: none;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.65rem 1.5rem;
  border: none;
  border-radius: 6px;
  font-size: 0.95rem;
  font-weight: 600;
  font-family: var(--font-body);
  cursor: pointer;
  transition: all 0.15s;
}

.btn-primary {
  background: var(--color-accent);
  color: white;
}

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

.btn-secondary {
  background: var(--color-input-bg);
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

/* Results */
.result-card {
  background: var(--color-result-bg);
  border: 1px solid #c8e6c9;
  border-radius: var(--radius);
  padding: 1.25rem;
  margin-top: 1.5rem;
  display: none;
}

.result-card.visible {
  display: block;
  animation: fadeIn 0.3s ease;
}

.result-value {
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-accent);
  line-height: 1.2;
}

.result-label {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  margin-top: 0.25rem;
}

.result-detail {
  margin-top: 1rem;
  font-size: 0.9rem;
  line-height: 1.6;
}

/* Callout boxes */
.callout {
  padding: 1rem 1.25rem;
  border-radius: var(--radius);
  font-size: 0.9rem;
  margin: 1rem 0;
}

.callout-info {
  background: var(--color-info-bg);
  border-left: 3px solid var(--color-info);
}

.callout-warning {
  background: var(--color-warning-bg);
  border-left: 3px solid var(--color-warning);
}

/* Disclosure / affiliate */
.disclosure {
  font-size: 0.75rem;
  color: var(--color-text-secondary);
  padding: 0.75rem;
  background: var(--color-input-bg);
  border-radius: var(--radius);
  margin-top: 2rem;
}

/* Responsive */
@media (max-width: 600px) {
  h1 { font-size: 1.4rem; }
  main { padding: 1.25rem 1rem; }
  .input-row { flex-direction: column; gap: 0; }
  .calc-section { padding: 1.25rem 1rem; }
  .result-value { font-size: 1.5rem; }
  .site-nav a { margin-left: 1rem; font-size: 0.8rem; }
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Canvas/Chart container */
.chart-container {
  margin-top: 1rem;
  background: var(--color-surface);
  border-radius: var(--radius);
  padding: 1rem;
  border: 1px solid var(--color-border);
}

.chart-container canvas {
  width: 100% !important;
  max-height: 300px;
}

/* Home page specific */
.hero {
  text-align: center;
  padding: 2rem 0 3rem;
}

.hero h1 {
  font-size: 2.25rem;
  letter-spacing: -0.03em;
  margin-bottom: 0.75rem;
}

.hero .subtitle {
  font-size: 1.1rem;
  color: var(--color-text-secondary);
  max-width: 500px;
  margin: 0 auto;
}

.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
  margin-top: 2rem;
}

.tool-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.25rem;
  text-decoration: none;
  color: var(--color-text);
  transition: all 0.15s;
  box-shadow: var(--shadow-sm);
}

.tool-card:hover {
  border-color: var(--color-accent);
  box-shadow: var(--shadow-md);
  text-decoration: none;
  transform: translateY(-1px);
}

.tool-card h3 {
  margin-top: 0;
  font-size: 1rem;
  color: var(--color-accent);
}

.tool-card p {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  margin-bottom: 0;
}

.section-label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-text-secondary);
  font-weight: 600;
  margin-bottom: 1rem;
}