/* =========================================================================
   Swimming Calculator — Premium Design System
   Ocean-inspired athletic performance dashboard
   ========================================================================= */

:root {
  --color-navy: #071A2B;
  --color-navy-soft: #0D2B45;
  --color-blue: #0B5FA5;
  --color-blue-deep: #084A82;
  --color-aqua: #18C7D9;
  --color-cyan: #7DEBF2;
  --color-surface: #F5FAFC;
  --color-surface-2: #EAF4F9;
  --color-surface-dark: #102A43;
  --color-ink: #102A43;
  --color-ink-soft: #243B53;
  --color-muted: #627D98;
  --color-border: #D9EAF0;
  --color-success: #168F63;
  --color-success-soft: #E6F4EE;
  --color-error: #D64545;
  --color-error-soft: #FBEAEA;
  --color-warning: #B7791F;
  --color-warning-soft: #FBF0DD;
  --color-white: #FFFFFF;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 999px;

  --shadow-sm: 0 1px 2px rgba(7, 26, 43, 0.06), 0 1px 3px rgba(7, 26, 43, 0.08);
  --shadow-md: 0 4px 12px rgba(7, 26, 43, 0.08), 0 2px 4px rgba(7, 26, 43, 0.06);
  --shadow-lg: 0 12px 32px rgba(7, 26, 43, 0.12), 0 4px 8px rgba(7, 26, 43, 0.06);
  --shadow-xl: 0 24px 60px rgba(7, 26, 43, 0.16);

  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --container-max: 1120px;
  --container-narrow: 720px;

  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 24px;
  --space-6: 32px;
  --space-7: 48px;
  --space-8: 64px;
  --space-9: 80px;

  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* ----- Reset & base ----- */

*, *::before, *::after { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.6;
  color: var(--color-ink);
  background: var(--color-surface);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
  margin: 0 0 var(--space-4);
  line-height: 1.2;
  font-weight: 700;
  color: var(--color-ink);
  letter-spacing: -0.02em;
}

h1 { font-size: clamp(2rem, 5vw, 3rem); }
h2 { font-size: clamp(1.5rem, 3.5vw, 2.1rem); }
h3 { font-size: clamp(1.2rem, 2.5vw, 1.5rem); }
h4 { font-size: 1.15rem; }

p { margin: 0 0 var(--space-4); }

a {
  color: var(--color-blue);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover { color: var(--color-aqua); }

ul, ol { margin: 0 0 var(--space-4); padding-left: 1.3em; }
li { margin-bottom: var(--space-2); }

img, svg { max-width: 100%; height: auto; display: block; }

code {
  font-family: var(--font-mono);
  font-size: 0.92em;
  background: var(--color-surface-2);
  padding: 2px 6px;
  border-radius: var(--radius-sm);
}

pre {
  background: var(--color-navy);
  color: var(--color-cyan);
  padding: var(--space-5);
  border-radius: var(--radius-md);
  overflow-x: auto;
  font-size: 0.9rem;
  line-height: 1.5;
}

pre code { background: none; padding: 0; }

/* ----- Layout ----- */

.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-4);
}

.container-narrow {
  max-width: var(--container-narrow);
}

.section { padding: var(--space-8) 0; }
.section-sm { padding: var(--space-7) 0; }
.section-tight { padding: var(--space-6) 0; }

.bg-surface { background: var(--color-surface); }
.bg-surface-2 { background: var(--color-surface-2); }
.bg-navy { background: var(--color-navy); color: var(--color-cyan); }
.bg-navy-soft { background: var(--color-navy-soft); color: var(--color-white); }
.bg-gradient-ocean {
  background: linear-gradient(135deg, var(--color-navy) 0%, var(--color-blue) 60%, var(--color-aqua) 130%);
  color: var(--color-white);
}

.text-center { text-align: center; }
.text-muted { color: var(--color-muted); }
.text-cyan { color: var(--color-cyan); }
.text-aqua { color: var(--color-aqua); }
.text-blue { color: var(--color-blue); }
.text-white { color: var(--color-white); }
.text-success { color: var(--color-success); }
.text-error { color: var(--color-error); }

.grid { display: grid; gap: var(--space-5); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.grid-auto { grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); }

.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.flex-wrap { flex-wrap: wrap; }
.gap-2 { gap: var(--space-2); }
.gap-3 { gap: var(--space-3); }
.gap-4 { gap: var(--space-4); }
.gap-5 { gap: var(--space-5); }

/* ----- Header / Nav ----- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(7, 26, 43, 0.96);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(125, 235, 242, 0.12);
  transition: background var(--transition-base);
}

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

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  color: var(--color-white);
  font-weight: 700;
  font-size: 1.15rem;
  letter-spacing: -0.02em;
}

.logo:hover { color: var(--color-cyan); }

.logo svg { width: 34px; height: 34px; }

.nav {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.nav-link {
  color: rgba(255,255,255,0.82);
  font-size: 0.95rem;
  font-weight: 500;
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.nav-link:hover { color: var(--color-white); background: rgba(125,235,242,0.1); }

.nav-link.primary {
  background: var(--color-aqua);
  color: var(--color-navy);
  font-weight: 600;
}

.nav-link.primary:hover { background: var(--color-cyan); color: var(--color-navy); }

/* Dropdown */
.nav-dropdown { position: relative; }
.nav-dropdown-toggle {
  display: flex; align-items: center; gap: 6px;
  color: rgba(255,255,255,0.82);
  font-size: 0.95rem; font-weight: 500;
  padding: 8px 14px; border-radius: var(--radius-sm);
  background: none; border: none; cursor: pointer;
  font-family: inherit;
}
.nav-dropdown-toggle:hover { color: var(--color-white); background: rgba(125,235,242,0.1); }
.nav-dropdown-toggle svg { width: 14px; height: 14px; }
.nav-dropdown-menu {
  position: absolute; top: 100%; left: 0;
  min-width: 260px;
  background: var(--color-white);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  padding: var(--space-2);
  display: none;
  grid-template-columns: 1fr 1fr;
  gap: 2px;
}
.nav-dropdown:hover .nav-dropdown-menu,
.nav-dropdown:focus-within .nav-dropdown-menu { display: grid; }
.nav-dropdown-menu a {
  color: var(--color-ink);
  font-size: 0.88rem;
  padding: 7px 10px;
  border-radius: var(--radius-sm);
}
.nav-dropdown-menu a:hover { background: var(--color-surface-2); color: var(--color-blue); }

.nav-toggle {
  display: none;
  background: none; border: none; cursor: pointer;
  width: 40px; height: 40px; padding: 0;
  color: var(--color-white);
}
.nav-toggle svg { width: 24px; height: 24px; }

/* ----- Hero ----- */

.hero {
  position: relative;
  background: linear-gradient(160deg, var(--color-navy) 0%, var(--color-navy-soft) 45%, var(--color-blue) 100%);
  color: var(--color-white);
  padding: var(--space-9) 0 var(--space-8);
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at 80% 20%, rgba(24,199,217,0.18) 0%, transparent 55%),
    radial-gradient(ellipse at 15% 85%, rgba(125,235,242,0.12) 0%, transparent 50%);
  pointer-events: none;
}

.hero-wave {
  position: absolute;
  bottom: -2px; left: 0; right: 0;
  width: 100%;
  pointer-events: none;
}

.hero .container { position: relative; z-index: 2; }

.hero h1 {
  color: var(--color-white);
  font-size: clamp(2.2rem, 5.5vw, 3.4rem);
  max-width: 720px;
}

.hero p {
  font-size: 1.2rem;
  color: rgba(255,255,255,0.86);
  max-width: 600px;
  margin-bottom: var(--space-6);
}

.hero-eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  background: rgba(125,235,242,0.14);
  border: 1px solid rgba(125,235,242,0.28);
  color: var(--color-cyan);
  font-size: 0.82rem; font-weight: 600;
  letter-spacing: 0.06em; text-transform: uppercase;
  padding: 6px 14px;
  border-radius: var(--radius-full);
  margin-bottom: var(--space-5);
}

.hero-actions { display: flex; gap: var(--space-4); flex-wrap: wrap; }

/* ----- Buttons ----- */

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  font-family: inherit; font-size: 1rem; font-weight: 600;
  padding: 13px 28px;
  border-radius: var(--radius-md);
  border: 2px solid transparent;
  cursor: pointer;
  transition: all var(--transition-base);
  text-decoration: none;
  line-height: 1;
}

.btn svg { width: 18px; height: 18px; }

.btn-primary {
  background: var(--color-aqua);
  color: var(--color-navy);
  box-shadow: 0 4px 16px rgba(24,199,217,0.35);
}
.btn-primary:hover { background: var(--color-cyan); color: var(--color-navy); transform: translateY(-2px); box-shadow: 0 8px 24px rgba(24,199,217,0.45); }

.btn-secondary {
  background: transparent;
  color: var(--color-white);
  border-color: rgba(255,255,255,0.4);
}
.btn-secondary:hover { border-color: var(--color-cyan); color: var(--color-cyan); }

.btn-ghost {
  background: var(--color-surface-2);
  color: var(--color-blue);
}
.btn-ghost:hover { background: var(--color-border); }

.btn-sm { padding: 9px 18px; font-size: 0.9rem; }
.btn-lg { padding: 16px 36px; font-size: 1.1rem; }

.btn-cta { width: 100%; padding: 16px 32px; font-size: 1.1rem; }

/* ----- Calculator cards grid ----- */

.calc-card {
  display: flex; flex-direction: column;
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.calc-card::before {
  content: "";
  position: absolute; top: 0; left: 0; right: 0; height: 3px;
  background: linear-gradient(90deg, var(--color-aqua), var(--color-blue));
  transform: scaleX(0); transform-origin: left;
  transition: transform var(--transition-base);
}

.calc-card:hover {
  border-color: var(--color-aqua);
  box-shadow: var(--shadow-lg);
  transform: translateY(-3px);
}

.calc-card:hover::before { transform: scaleX(1); }

.calc-card-icon {
  width: 52px; height: 52px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, rgba(11,95,165,0.1), rgba(24,199,217,0.16));
  display: flex; align-items: center; justify-content: center;
  color: var(--color-blue);
  margin-bottom: var(--space-4);
}
.calc-card-icon svg { width: 26px; height: 26px; }

.calc-card h3 { margin-bottom: var(--space-2); }
.calc-card p { color: var(--color-muted); font-size: 0.95rem; margin-bottom: var(--space-4); flex-grow: 1; }
.calc-card .card-link {
  font-weight: 600; font-size: 0.95rem; display: inline-flex; align-items: center; gap: 6px;
}
.calc-card .card-link svg { width: 16px; height: 16px; transition: transform var(--transition-fast); }
.calc-card:hover .card-link svg { transform: translateX(4px); }

/* Category section */
.cat-section { margin-bottom: var(--space-8); }
.cat-header {
  display: flex; align-items: center; gap: var(--space-3);
  margin-bottom: var(--space-5);
  padding-bottom: var(--space-3);
  border-bottom: 2px solid var(--color-border);
}
.cat-header .cat-icon {
  width: 44px; height: 44px; border-radius: var(--radius-md);
  background: var(--color-navy); color: var(--color-aqua);
  display: flex; align-items: center; justify-content: center; flex-shrink: 0;
}
.cat-header .cat-icon svg { width: 24px; height: 24px; }
.cat-header h2 { margin: 0; }

/* ----- Calculator widget ----- */

.calc-widget {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-7);
  box-shadow: var(--shadow-lg);
}

.calc-widget h2 { margin-bottom: var(--space-5); }

.field { margin-bottom: var(--space-5); }
.field:last-child { margin-bottom: 0; }

.field-label {
  display: block;
  font-weight: 600;
  font-size: 0.95rem;
  margin-bottom: var(--space-2);
  color: var(--color-ink-soft);
}

.field-hint {
  font-size: 0.85rem;
  color: var(--color-muted);
  margin-top: var(--space-1);
}

.field-row { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-4); }
.field-row-3 { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: var(--space-4); }

.input, .select {
  width: 100%;
  font-family: inherit;
  font-size: 1.05rem;
  padding: 13px 16px;
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-white);
  color: var(--color-ink);
  transition: all var(--transition-fast);
}

.input:focus, .select:focus {
  outline: none;
  border-color: var(--color-aqua);
  box-shadow: 0 0 0 4px rgba(24,199,217,0.14);
}

.input::placeholder { color: var(--color-muted); }

.input-group {
  position: relative;
  display: flex;
  align-items: center;
}
.input-group .input { padding-right: 56px; }
.input-group .input-suffix {
  position: absolute; right: 14px;
  color: var(--color-muted); font-size: 0.9rem; font-weight: 500;
  pointer-events: none;
}

/* Toggle / unit switch */
.unit-toggle {
  display: inline-flex;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  padding: 4px;
  gap: 2px;
}
.unit-toggle button {
  border: none; background: none; cursor: pointer;
  font-family: inherit; font-size: 0.9rem; font-weight: 600;
  padding: 7px 18px; border-radius: var(--radius-full);
  color: var(--color-muted);
  transition: all var(--transition-fast);
}
.unit-toggle button.active {
  background: var(--color-blue);
  color: var(--color-white);
  box-shadow: var(--shadow-sm);
}

/* ----- Results ----- */

.result-panel {
  background: linear-gradient(160deg, var(--color-navy) 0%, var(--color-navy-soft) 100%);
  border-radius: var(--radius-lg);
  padding: var(--space-7);
  color: var(--color-white);
  margin-top: var(--space-6);
  display: none;
}
.result-panel.visible {
  display: block;
  animation: fadeSlideIn 0.5s cubic-bezier(0.4,0,0.2,1);
}

.result-label {
  font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.1em;
  color: var(--color-cyan); font-weight: 600; margin-bottom: var(--space-2);
}
.result-value {
  font-size: clamp(2.2rem, 5vw, 3.2rem); font-weight: 700; line-height: 1.1;
  font-family: var(--font-mono);
  letter-spacing: -0.02em;
  color: var(--color-white);
  margin-bottom: var(--space-2);
}
.result-unit { font-size: 1.1rem; color: rgba(255,255,255,0.6); font-weight: 500; }

.result-detail {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: var(--space-4);
  margin-top: var(--space-6);
  padding-top: var(--space-6);
  border-top: 1px solid rgba(125,235,242,0.18);
}
.result-detail-item .result-label { margin-bottom: 4px; }
.result-detail-item .result-detail-value {
  font-size: 1.4rem; font-weight: 700; color: var(--color-cyan); font-family: var(--font-mono);
}

.result-interp {
  background: rgba(125,235,242,0.08);
  border: 1px solid rgba(125,235,242,0.2);
  border-radius: var(--radius-md);
  padding: var(--space-5);
  margin-top: var(--space-5);
}
.result-interp p:last-child { margin-bottom: 0; }
.result-interp strong { color: var(--color-cyan); }

.result-actions {
  display: flex; gap: var(--space-3); flex-wrap: wrap;
  margin-top: var(--space-5);
}

.result-error {
  background: var(--color-error-soft);
  border: 1px solid rgba(214,69,69,0.3);
  color: var(--color-error);
  padding: var(--space-4) var(--space-5);
  border-radius: var(--radius-md);
  margin-top: var(--space-5);
  display: none;
  font-size: 0.95rem;
}
.result-error.visible { display: block; animation: fadeSlideIn 0.3s ease; }

/* ----- Info / content sections ----- */

.prose { max-width: 760px; }
.prose p, .prose ul, .prose ol { font-size: 1.05rem; line-height: 1.7; }
.prose h2 { margin-top: var(--space-7); }
.prose h3 { margin-top: var(--space-6); }

.info-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-sm);
}
.info-card h3 { margin-bottom: var(--space-3); }
.info-card p { color: var(--color-ink-soft); margin-bottom: 0; }

.callout {
  background: linear-gradient(135deg, rgba(11,95,165,0.06), rgba(24,199,217,0.08));
  border-left: 4px solid var(--color-aqua);
  border-radius: var(--radius-md);
  padding: var(--space-5) var(--space-6);
  margin: var(--space-5) 0;
}
.callout-title { font-weight: 700; margin-bottom: var(--space-2); color: var(--color-blue); }
.callout p:last-child { margin-bottom: 0; }

.callout.warning { border-left-color: var(--color-warning); background: rgba(183,121,31,0.06); }
.callout.warning .callout-title { color: var(--color-warning); }

/* ----- Formula box ----- */
.formula-box {
  background: var(--color-navy);
  color: var(--color-cyan);
  border-radius: var(--radius-md);
  padding: var(--space-5) var(--space-6);
  margin: var(--space-5) 0;
  font-family: var(--font-mono);
  font-size: 1.05rem;
  overflow-x: auto;
}
.formula-box .formula-label {
  font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.1em;
  color: rgba(125,235,242,0.6); margin-bottom: var(--space-2);
}

/* ----- Table ----- */
.table-wrap { overflow-x: auto; border-radius: var(--radius-md); border: 1px solid var(--color-border); }
table { width: 100%; border-collapse: collapse; font-size: 0.95rem; background: var(--color-white); }
th { background: var(--color-surface-2); text-align: left; padding: var(--space-3) var(--space-4); font-weight: 700; color: var(--color-ink-soft); border-bottom: 2px solid var(--color-border); }
td { padding: var(--space-3) var(--space-4); border-bottom: 1px solid var(--color-border); }
tr:last-child td { border-bottom: none; }
tr:hover td { background: var(--color-surface); }

/* ----- FAQ ----- */
.faq-item {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-3);
  background: var(--color-white);
  overflow: hidden;
}
.faq-question {
  width: 100%; text-align: left; background: none; border: none; cursor: pointer;
  font-family: inherit; font-size: 1.05rem; font-weight: 600;
  padding: var(--space-4) var(--space-5); color: var(--color-ink);
  display: flex; justify-content: space-between; align-items: center; gap: var(--space-3);
}
.faq-question:hover { background: var(--color-surface); }
.faq-question .faq-icon { width: 20px; height: 20px; flex-shrink: 0; color: var(--color-blue); transition: transform var(--transition-base); }
.faq-item.open .faq-question .faq-icon { transform: rotate(45deg); }
.faq-answer { max-height: 0; overflow: hidden; transition: max-height var(--transition-base); }
.faq-item.open .faq-answer { max-height: 600px; }
.faq-answer-inner { padding: 0 var(--space-5) var(--space-5); color: var(--color-ink-soft); }

/* ----- Breadcrumbs ----- */
.breadcrumbs {
  padding: var(--space-4) 0;
  font-size: 0.88rem;
  color: var(--color-muted);
}
.breadcrumbs ol { list-style: none; margin: 0; padding: 0; display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.breadcrumbs li { display: flex; align-items: center; gap: 8px; }
.breadcrumbs li::after { content: "/"; color: var(--color-border); }
.breadcrumbs li:last-child::after { display: none; }
.breadcrumbs a { color: var(--color-blue); }
.breadcrumbs span { color: var(--color-muted); }

/* ----- Related links ----- */
.related-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px,1fr)); gap: var(--space-4); }
.related-link {
  display: flex; align-items: center; gap: var(--space-3);
  padding: var(--space-4);
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}
.related-link:hover { border-color: var(--color-aqua); transform: translateX(4px); box-shadow: var(--shadow-sm); }
.related-link svg { width: 18px; height: 18px; color: var(--color-aqua); flex-shrink: 0; }
.related-link span { font-weight: 600; font-size: 0.95rem; }

/* ----- Footer ----- */
.site-footer {
  background: var(--color-navy);
  color: rgba(255,255,255,0.7);
  padding: var(--space-8) 0 var(--space-5);
  margin-top: var(--space-8);
}
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: var(--space-6); margin-bottom: var(--space-6); }
.footer-brand .logo { margin-bottom: var(--space-3); }
.footer-brand p { font-size: 0.92rem; color: rgba(255,255,255,0.55); max-width: 320px; }
.footer-col h4 { color: var(--color-white); font-size: 0.85rem; text-transform: uppercase; letter-spacing: 0.08em; margin-bottom: var(--space-3); }
.footer-col ul { list-style: none; padding: 0; margin: 0; }
.footer-col li { margin-bottom: var(--space-2); }
.footer-col a { color: rgba(255,255,255,0.65); font-size: 0.92rem; }
.footer-col a:hover { color: var(--color-cyan); }
.footer-bottom {
  border-top: 1px solid rgba(125,235,242,0.12);
  padding-top: var(--space-5);
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: var(--space-3);
  font-size: 0.85rem; color: rgba(255,255,255,0.45);
}
.footer-bottom a { color: rgba(255,255,255,0.45); }
.footer-bottom a:hover { color: var(--color-cyan); }

/* ----- Stats band ----- */
.stats-band {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(160px,1fr));
  gap: var(--space-5); text-align: center;
}
.stat-item .stat-num { font-size: 2.2rem; font-weight: 700; color: var(--color-aqua); font-family: var(--font-mono); }
.stat-item .stat-label { font-size: 0.88rem; color: rgba(255,255,255,0.7); }

/* ----- Page hero (sub pages) ----- */
.page-hero {
  background: linear-gradient(160deg, var(--color-navy) 0%, var(--color-navy-soft) 70%, var(--color-blue) 100%);
  color: var(--color-white);
  padding: var(--space-7) 0 var(--space-6);
  position: relative;
  overflow: hidden;
}
.page-hero::before {
  content: ""; position: absolute; inset: 0;
  background: radial-gradient(ellipse at 90% 30%, rgba(24,199,217,0.14) 0%, transparent 55%);
}
.page-hero .container { position: relative; }
.page-hero h1 { color: var(--color-white); margin-bottom: var(--space-3); }
.page-hero p { color: rgba(255,255,255,0.82); font-size: 1.15rem; max-width: 640px; margin-bottom: 0; }
.page-hero .hero-eyebrow { margin-bottom: var(--space-4); }

/* ----- Badges ----- */
.badge {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: 0.78rem; font-weight: 600;
  padding: 4px 10px; border-radius: var(--radius-full);
}
.badge-aqua { background: rgba(24,199,217,0.14); color: var(--color-blue); }
.badge-success { background: var(--color-success-soft); color: var(--color-success); }
.badge-muted { background: var(--color-surface-2); color: var(--color-muted); }

/* ----- Two-column layout (calc + content) ----- */
.calc-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-6);
  align-items: start;
}
.calc-layout .calc-sticky { position: sticky; top: 88px; }

/* ----- Formulas page ----- */
.formula-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  margin-bottom: var(--space-5);
}
.formula-card h3 { color: var(--color-blue); }
.formula-card .formula-box { margin: var(--space-3) 0; }

/* ----- Glossary ----- */
.glossary-list { display: grid; gap: var(--space-3); }
.glossary-item {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-4) var(--space-5);
}
.glossary-item dt { font-weight: 700; color: var(--color-blue); font-size: 1.05rem; margin-bottom: 4px; }
.glossary-item dd { margin: 0; color: var(--color-ink-soft); }

/* ----- 404 ----- */
.error-page { min-height: 70vh; display: flex; align-items: center; justify-content: center; text-align: center; }

/* ----- Animations ----- */
@keyframes fadeSlideIn {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes waveMove {
  0% { transform: translateX(0); }
  100% { transform: translateX(-50%); }
}
.reveal { opacity: 0; transform: translateY(24px); transition: opacity 0.6s ease, transform 0.6s ease; }
.reveal.visible { opacity: 1; transform: none; }

/* ----- Mobile nav drawer ----- */
.mobile-nav {
  display: none;
  position: fixed; top: 64px; left: 0; right: 0; bottom: 0;
  background: var(--color-navy);
  padding: var(--space-5);
  overflow-y: auto;
  z-index: 99;
}
.mobile-nav.open { display: block; }
.mobile-nav a {
  display: block; color: var(--color-white); font-size: 1.1rem; font-weight: 500;
  padding: var(--space-3) var(--space-4); border-radius: var(--radius-sm);
}
.mobile-nav a:hover { background: rgba(125,235,242,0.1); color: var(--color-cyan); }
.mobile-nav .m-section { color: var(--color-cyan); font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.1em; margin-top: var(--space-4); margin-bottom: var(--space-2); padding-left: var(--space-4); }

/* ----- Responsive ----- */
@media (max-width: 900px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .calc-layout { grid-template-columns: 1fr; }
  .calc-layout .calc-sticky { position: static; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 720px) {
  .nav, .nav-dropdown { display: none; }
  .nav-toggle { display: flex; align-items: center; justify-content: center; }
  .field-row, .field-row-3 { grid-template-columns: 1fr; }
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .calc-widget { padding: var(--space-5); }
  .result-panel { padding: var(--space-5); }
  .section { padding: var(--space-7) 0; }
  body { font-size: 16px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* Skip link for accessibility */
.skip-link {
  position: absolute; left: -999px; top: 0;
  background: var(--color-aqua); color: var(--color-navy);
  padding: var(--space-3) var(--space-4); border-radius: 0 0 var(--radius-md) 0;
  font-weight: 600; z-index: 200;
}
.skip-link:focus { left: 0; }