/* ===== Design tokens ===== */
:root {
  --bg: #ffffff;
  --surface: #ffffff;
  --text: #1c2233;
  --muted: #5b6478;
  --border: #dde2ee;
  --primary: #3535e6;
  --primary-soft: #e6e5fd;
  --accent: #0ea5a4;
  --danger: #c2410c;
  --shadow: 0 4px 20px rgba(28, 34, 51, 0.06);
  --radius: 16px;

  --r-frontal: #818cf8;
  --r-parietal: #34d399;
  --r-temporal: #fbbf24;
  --r-occipital: #f472b6;
  --r-cerebellum: #60a5fa;
  --r-brainstem: #a78bfa;
}

/* ===== Base ===== */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 80px; }
body {
  margin: 0;
  font-family: "Inter", system-ui, -apple-system, Segoe UI, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}
h1, h2, h3 { line-height: 1.2; margin: 0 0 0.5em; }
h1, h2 { font-family: "Fraunces", Georgia, serif; }
h1 { font-size: clamp(2.2rem, 5vw, 3.5rem); }
h2 { font-size: clamp(1.8rem, 3.5vw, 2.5rem); }
h3 { font-size: 1.15rem; }
p { margin: 0 0 1em; }
a { color: var(--primary); }
img, svg { max-width: 100%; }

.container { width: min(1120px, 100% - 32px); margin-inline: auto; }
.narrow { width: min(760px, 100% - 32px); }
.section { padding: 80px 0; }
.section.alt { border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }
.eyebrow {
  text-transform: uppercase; letter-spacing: 0.12em;
  font-size: 0.78rem; font-weight: 700; color: var(--accent); margin-bottom: 0.5em;
}
.section-intro { color: var(--muted); max-width: 680px; font-size: 1.05rem; margin-bottom: 2em; }
.muted { color: var(--muted); }
.sub-heading { margin-top: 3rem; }

/* ===== Alert bar ===== */
.alert-bar {
  background: var(--danger); color: #fff; text-align: center;
  padding: 10px 16px; font-size: 0.9rem;
}
.alert-bar a { color: #fff; font-weight: 600; margin-left: 8px; }

/* ===== Header / Nav ===== */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: #fff;
  border-bottom: 1px solid var(--border);
}
.nav { display: flex; align-items: center; gap: 16px; height: 64px; }
.logo {
  display: flex; align-items: center; gap: 8px;
  font-weight: 700; font-size: 1.2rem; text-decoration: none; color: var(--text);
}
.logo-mark { width: 40px; height: 40px; display: block; }
.nav-links { display: flex; gap: 4px; list-style: none; margin: 0 0 0 auto; padding: 0; }
.nav-links a {
  text-decoration: none; color: var(--muted); font-weight: 500; font-size: 0.92rem;
  padding: 8px 10px; border-radius: 8px; transition: 0.2s;
}
.nav-links a:hover, .nav-links a.active { color: var(--primary); background: var(--primary-soft); }
.nav-toggle { display: none; }

/* ===== Buttons ===== */
.btn {
  display: inline-block; padding: 12px 24px; border-radius: 999px;
  font-weight: 600; text-decoration: none; border: 2px solid transparent;
  cursor: pointer; font-size: 1rem; font-family: inherit; transition: 0.2s;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { filter: brightness(1.1); transform: translateY(-1px); }
.btn-ghost { border-color: var(--primary); color: var(--primary); }
.btn-ghost:hover { background: var(--primary-soft); }
.btn-link { background: none; border: none; color: var(--danger); cursor: pointer; font: inherit; font-size: 0.9rem; }

/* ===== Hero ===== */
.hero {
  padding: 90px 0 70px;
}
.hero-grid { display: grid; grid-template-columns: 1.3fr 1fr; gap: 48px; align-items: center; }
.lead { font-size: 1.15rem; color: var(--muted); max-width: 560px; }
.hero-actions { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 1.5em; }
.hero-stats { display: grid; gap: 16px; }
.stat {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 18px 22px; box-shadow: var(--shadow);
}
.stat-num, .stat-unit { font-family: "Fraunces", serif; font-size: 2rem; font-weight: 700; color: var(--primary); }
.stat-unit { margin-left: 4px; font-size: 1.4rem; }
.stat p { margin: 4px 0 0; color: var(--muted); font-size: 0.92rem; }

/* ===== Cards ===== */
.card-grid { display: grid; gap: 20px; }
.card-grid.two { grid-template-columns: repeat(2, 1fr); }
.card-grid.three { grid-template-columns: repeat(3, 1fr); }
.card-grid.four { grid-template-columns: repeat(4, 1fr); }
.card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 26px; box-shadow: var(--shadow);
}
.card-icon { font-size: 2rem; margin-bottom: 8px; }
.check-list { padding: 0; list-style: none; margin: 0; }
.check-list li { padding-left: 26px; position: relative; margin: 6px 0; }
.check-list li::before {
  content: "✓"; position: absolute; left: 0; color: var(--accent); font-weight: 700;
}
.health-card { border-top: 4px solid var(--accent); transition: transform 0.2s; }
.health-card:hover { transform: translateY(-4px); }
.health-card p { color: var(--muted); margin: 0; }

/* Severity */
.severity { margin-top: 40px; }
.severity-scale { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.sev { padding: 20px; background: #fff; border: 1px solid var(--border); border-top: 6px solid; border-radius: var(--radius); }
.sev strong { display: block; font-size: 1.1rem; margin-bottom: 4px; }
.sev span { font-size: 0.92rem; }
.sev-mild { border-top-color: #22c55e; }
.sev-moderate { border-top-color: #f59e0b; }
.sev-severe { border-top-color: #ef4444; }

/* Flip cards */
.flip-card {
  background: none; border: none; padding: 0; perspective: 1000px;
  height: 200px; cursor: pointer; font: inherit; color: inherit; text-align: left;
}
.flip-inner {
  position: relative; width: 100%; height: 100%;
  transition: transform 0.6s; transform-style: preserve-3d;
}
.flip-card.flipped .flip-inner { transform: rotateY(180deg); }
.flip-front, .flip-back {
  position: absolute; inset: 0; backface-visibility: hidden;
  border-radius: var(--radius); padding: 24px;
  display: flex; flex-direction: column; justify-content: center;
  border: 1px solid var(--border); box-shadow: var(--shadow);
}
.flip-front { background: var(--surface); }
.flip-front p { color: var(--muted); margin: 0; }
.flip-front::after { content: "Tap to flip ↻"; font-size: 0.8rem; color: var(--primary); margin-top: 12px; }
.flip-back {
  background: var(--primary); color: #fff; transform: rotateY(180deg); font-size: 0.95rem;
}
.flip-back p { margin: 0; }

/* ===== Brain map ===== */
.brain-layout { display: grid; grid-template-columns: 1.2fr 1fr; gap: 32px; align-items: start; }
.brain-figure { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px; box-shadow: var(--shadow); }
.brain-svg { width: 100%; height: auto; display: block; }
.region {
  stroke: var(--surface); stroke-width: 3; cursor: pointer;
  transition: opacity 0.2s, transform 0.2s; opacity: 0.85; outline: none;
}
.region[data-region="frontal"] { fill: var(--r-frontal); }
.region[data-region="parietal"] { fill: var(--r-parietal); }
.region[data-region="temporal"] { fill: var(--r-temporal); }
.region[data-region="occipital"] { fill: var(--r-occipital); }
.region[data-region="cerebellum"] { fill: var(--r-cerebellum); }
.region[data-region="brainstem"] { fill: var(--r-brainstem); }
.region:hover, .region:focus-visible { opacity: 1; }
.brain-svg.has-active .region { opacity: 0.35; }
.brain-svg.has-active .region.active { opacity: 1; stroke: var(--text); }
.brain-legend { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 16px; justify-content: center; }
.brain-legend button {
  border: 1px solid var(--border); background: var(--bg); color: var(--text);
  padding: 6px 12px; border-radius: 999px; cursor: pointer; font: inherit; font-size: 0.85rem;
  display: flex; align-items: center; gap: 6px;
}
.brain-legend button::before { content: ""; width: 10px; height: 10px; border-radius: 50%; background: var(--dot); }
.brain-legend button.active { border-color: var(--primary); background: var(--primary-soft); }
.brain-info h3 { font-size: 1.4rem; }
.brain-info h4 { margin: 1em 0 0.4em; font-size: 0.95rem; color: var(--accent); }
.brain-info ul { margin: 0; padding-left: 20px; }

/* ===== Tabs ===== */
.tabs { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 20px; }
.tab {
  border: 1px solid var(--border); background: var(--surface); color: var(--text);
  padding: 10px 20px; border-radius: 999px; cursor: pointer; font: inherit; font-weight: 500;
}
.tab.active { background: var(--primary); color: #fff; border-color: var(--primary); }
.tab-panel { animation: fade 0.3s; }
@keyframes fade { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }
.pill-list { display: flex; flex-wrap: wrap; gap: 10px; list-style: none; padding: 0; margin: 0; }
.pill-list li {
  background: var(--surface); border: 1px solid var(--border);
  padding: 10px 16px; border-radius: 12px; box-shadow: var(--shadow);
}

/* Warning */
.warning { margin-top: 40px; border: 2px solid var(--danger); }
.warning h3 { color: var(--danger); }
.warning-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 0 24px; }
.warning ul { margin: 0; padding-left: 20px; }
.warning li { margin: 6px 0; }
.warning-cta { margin: 16px 0 0; font-size: 1.1rem; }

/* ===== Timeline ===== */
.timeline { list-style: none; padding: 0; margin: 0; position: relative; }
.timeline::before {
  content: ""; position: absolute; left: 21px; top: 10px; bottom: 10px;
  width: 2px; background: var(--border);
}
.timeline li { display: flex; gap: 20px; margin-bottom: 28px; position: relative; }
.tl-dot {
  flex: none; width: 44px; height: 44px; border-radius: 50%;
  background: var(--primary); color: #fff; display: grid; place-items: center; font-weight: 700;
}
.timeline p { color: var(--muted); margin: 0; }

.tip {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 20px; text-align: center;
}
.tip span { font-size: 1.8rem; }
.tip p { margin: 8px 0 0; font-size: 0.93rem; }

/* ===== Tracker ===== */
.tracker-layout { display: grid; grid-template-columns: 1fr 1.2fr; gap: 24px; align-items: start; }
.tracker-form { display: grid; gap: 16px; }
.tracker-form label { display: grid; gap: 6px; font-weight: 500; font-size: 0.95rem; }
.tracker-form label output { font-weight: 700; color: var(--primary); }
.tracker-form label:has(output) { grid-template-columns: 1fr auto; }
.tracker-form label:has(output) input { grid-column: 1 / -1; }
.tracker-form input[type="date"],
.tracker-form input[type="number"],
.tracker-form textarea {
  font: inherit; padding: 10px 12px; border-radius: 10px;
  border: 1px solid var(--border); background: var(--bg); color: var(--text);
}
.tracker-form input[type="range"] { accent-color: var(--primary); width: 100%; }
.log-head { display: flex; justify-content: space-between; align-items: center; }
.log-list { list-style: none; padding: 0; margin: 0; display: grid; gap: 10px; max-height: 420px; overflow-y: auto; }
.log-list li {
  border: 1px solid var(--border); border-radius: 12px; padding: 12px 14px; background: var(--bg);
  display: grid; grid-template-columns: 1fr auto; gap: 4px 12px;
}
.log-date { font-weight: 600; }
.log-meta { display: flex; flex-wrap: wrap; gap: 6px; grid-column: 1 / -1; }
.log-meta span { font-size: 0.8rem; padding: 2px 8px; border-radius: 999px; background: var(--primary-soft); }
.log-notes { grid-column: 1 / -1; color: var(--muted); font-size: 0.88rem; margin: 0; }
.log-del { background: none; border: none; color: var(--muted); cursor: pointer; font-size: 1.1rem; }
.log-del:hover { color: var(--danger); }

/* ===== FAQ ===== */
.accordion { display: grid; gap: 12px; }
.accordion details {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 12px; padding: 0 20px;
}
.accordion summary {
  cursor: pointer; padding: 18px 0; font-weight: 600; list-style: none;
  display: flex; justify-content: space-between; align-items: center; gap: 12px;
}
.accordion summary::-webkit-details-marker { display: none; }
.accordion summary::after { content: "+"; font-size: 1.4rem; color: var(--primary); transition: transform 0.2s; }
.accordion details[open] summary::after { transform: rotate(45deg); }
.accordion details p { color: var(--muted); padding-bottom: 18px; margin: 0; }

/* ===== Resources ===== */
.resource { text-decoration: none; color: var(--text); transition: transform 0.2s, border-color 0.2s; }
.resource:hover { transform: translateY(-4px); border-color: var(--primary); }
.resource p { color: var(--muted); }
.arrow { color: var(--primary); font-weight: 600; }

/* ===== Footer ===== */
.site-footer { background: var(--surface); border-top: 1px solid var(--border); padding: 40px 0; text-align: center; }
.disclaimer { max-width: 760px; margin: 0 auto 1em; font-size: 0.92rem; }

.to-top {
  position: fixed; right: 20px; bottom: 20px; width: 48px; height: 48px;
  border-radius: 50%; border: none; background: var(--primary); color: #fff;
  font-size: 1.3rem; cursor: pointer; box-shadow: var(--shadow);
  opacity: 0; pointer-events: none; transition: opacity 0.3s;
}
.to-top.show { opacity: 1; pointer-events: auto; }

/* Reveal on scroll */
.reveal { opacity: 0; transform: translateY(20px); transition: opacity 0.6s, transform 0.6s; }
.reveal.visible { opacity: 1; transform: none; }

/* ===== Responsive ===== */
@media (max-width: 960px) {
  .card-grid.three { grid-template-columns: repeat(2, 1fr); }
  .card-grid.four { grid-template-columns: repeat(2, 1fr); }
  .hero-grid, .brain-layout, .tracker-layout { grid-template-columns: 1fr; }

  .nav-toggle {
    display: flex; flex-direction: column; gap: 5px; margin-left: auto;
    background: none; border: none; cursor: pointer; padding: 8px;
  }
  .nav-toggle span { width: 22px; height: 2px; background: var(--text); transition: 0.3s; }
  .nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
  .nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
  .nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }
  .nav-links {
    position: absolute; top: 64px; left: 0; right: 0; flex-direction: column;
    background: var(--surface); border-bottom: 1px solid var(--border);
    padding: 12px 16px; display: none;
  }
  .nav-links.open { display: flex; }
}

@media (max-width: 600px) {
  .section { padding: 56px 0; }
  .card-grid.two, .card-grid.three, .severity-scale, .warning-grid { grid-template-columns: 1fr; }
  .card-grid.four { grid-template-columns: 1fr 1fr; }
  .hero { padding: 56px 0 48px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
  .reveal { opacity: 1; transform: none; }
}

/* ===== Logo ===== */
.hero-logo { display: block; width: min(340px, 80%); height: auto; margin: 0 0 24px -8px; }
.footer-logo { display: block; width: 180px; height: auto; margin: 0 auto 16px; }

/* ===== Multi-page ===== */
.page-card { display: flex; flex-direction: column; }
.page-card p { flex: 1; }
.page-icon { font-size: 2rem; margin-bottom: 8px; }
.warning .btn { margin-top: 8px; }

.pager {
  display: grid; grid-template-columns: 1fr 1fr; gap: 16px;
  padding: 0 0 64px; margin-top: 8px;
}
.pager a {
  display: flex; flex-direction: column; gap: 2px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 16px 20px; text-decoration: none; color: var(--text); font-weight: 600;
  box-shadow: var(--shadow); transition: border-color 0.2s, transform 0.2s;
}
.pager a:hover { border-color: var(--primary); transform: translateY(-2px); }
.pager a span { font-size: 0.82rem; font-weight: 500; color: var(--primary); }
.pager-next { text-align: right; grid-column: 2; }
.section + .pager { padding-top: 0; }
.section.alt + .pager { padding-top: 32px; }
@media (max-width: 600px) {
  .pager { grid-template-columns: 1fr; }
  .pager-next { grid-column: 1; }
}