/* ==========================================================================
   Polar Expert — Global styles
   Design tokens sourced from /design/DESIGN.md ("Polar Journal")
   ========================================================================== */

:root {
  /* Colors */
  --color-bg: #f9f9ff;
  --color-bg-alt: #f0f3ff;
  --color-bg-container: #e7eeff;
  --color-bg-highest: #d8e3fa;
  --color-surface: #ffffff;
  --color-text: #111c2c;
  --color-text-variant: #44474c;
  --color-primary: #0b1f33;
  --color-on-primary: #ffffff;
  --color-accent-bg: #ffdcc3;
  --color-accent-text: #2f1500;
  --color-accent-strong: #ffb77d;
  --color-border: #c4c6cd;
  --color-border-light: rgba(11, 31, 51, 0.12);
  --color-success: #506167;
  --color-secondary-container: #d1e3ea;
  --color-coral: #e08e45;

  /* Layout */
  --max-width: 1120px;
  --column-max: 720px;
  --gutter: 24px;
  --stack-sm: 8px;
  --stack-md: 16px;
  --stack-lg: 32px;
  --section-gap: 80px;
  --section-gap-mobile: 48px;
  --radius-sm: 4px;
  --radius-lg: 8px;

  /* Type */
  --font-display: "Source Serif 4", Georgia, "Times New Roman", serif;
  --font-body: "Hanken Grotesk", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

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

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

body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 24px;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }

a { color: inherit; }

h1, h2, h3 {
  font-family: var(--font-display);
  color: var(--color-primary);
  margin: 0;
}
h4 { margin: 0; }

p { margin: 0; }
ul { margin: 0; padding: 0; }
sup {
  font-size: 0.7em;
  line-height: 0;
  position: relative;
  top: -0.5em;
  vertical-align: baseline;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

.col {
  max-width: var(--column-max);
  margin: 0 auto;
}

.section {
  padding: var(--section-gap-mobile) 0;
}
@media (min-width: 768px) {
  .section { padding: var(--section-gap) 0; }
}
.section--bordered { border-top: 1px solid var(--color-border-light); border-bottom: 1px solid var(--color-border-light); }
.section--tint { background: var(--color-bg-container); }
.section--tint-low { background: var(--color-bg-alt); }

.label-caps {
  font-family: var(--font-body);
  font-size: 12px;
  line-height: 16px;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--color-text-variant);
}

.lead {
  font-size: 18px;
  line-height: 28px;
  color: var(--color-text-variant);
}

.muted { color: var(--color-text-variant); }
.center { text-align: center; }
.nowrap { white-space: nowrap; }

/* ---------- Header / Nav ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border-light);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
}
.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.site-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-display);
  font-size: 24px;
  font-weight: 700;
  color: var(--color-text);
  text-decoration: none;
}
.site-logo .material-symbols-outlined { color: var(--color-primary); }

.site-nav {
  display: none;
  align-items: center;
  gap: 24px;
}
.site-nav.is-open {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 16px;
  position: absolute;
  top: 64px;
  left: 0;
  right: 0;
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border-light);
  padding: var(--stack-md) var(--gutter);
}
.nav-link {
  display: inline-flex;
  align-items: center;
  font-family: var(--font-body);
  font-size: 12px;
  line-height: 16px;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--color-text-variant);
  text-decoration: none;
  padding-bottom: 4px;
  border-bottom: 2px solid transparent;
  transition: color 0.2s ease, border-color 0.2s ease;
}
.nav-link:hover { color: var(--color-text); }
.nav-link.is-active {
  color: var(--color-text);
  border-bottom-color: var(--color-text);
}
.nav-toggle {
  display: inline-flex;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--color-text);
  padding: 4px;
}
@media (min-width: 768px) {
  .site-nav { display: flex; }
  .nav-toggle { display: none; }
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-block;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  border-radius: var(--radius-sm);
  padding: 12px 24px;
  text-decoration: none;
  transition: opacity 0.2s ease, background-color 0.2s ease, color 0.2s ease;
  cursor: pointer;
}
.btn--primary { background: var(--color-primary); color: var(--color-on-primary); border: 1px solid var(--color-primary); }
.btn--primary:hover { opacity: 0.9; }
.btn--secondary { background: transparent; color: var(--color-primary); border: 1px solid var(--color-primary); }
.btn--secondary:hover { background: var(--color-bg-container); }
.btn--pill {
  background: var(--color-secondary-container);
  color: var(--color-primary);
  border: none;
  border-radius: 999px;
  padding: 10px 20px;
}
.btn--pill:hover { background: var(--color-primary); color: var(--color-on-primary); }
.card-cta { margin-top: var(--stack-md); align-self: center; }
.text-link {
  display: inline-block;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--color-primary);
  border-bottom: 1px solid var(--color-primary);
  padding-bottom: 2px;
  text-decoration: none;
  transition: opacity 0.2s ease;
}
.text-link:hover { opacity: 0.7; }

/* ---------- Badges ---------- */
.badge {
  display: inline-block;
  text-align: center;
  white-space: nowrap;
  font-size: 9px;
  font-weight: 700;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  padding: 4px 8px;
  border-radius: 999px;
  background: var(--color-bg-container);
  color: var(--color-text-variant);
  text-decoration: none;
}
.badge--accent {
  background: var(--color-accent-bg);
  color: var(--color-accent-text);
}
a.badge:hover { opacity: 0.85; }

/* ---------- Badge text (Operator Matrix Badge row) ---------- */
.badge-text {
  display: inline-block;
  font-family: var(--font-body);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.05em;
  line-height: 16px;
  text-transform: uppercase;
  color: var(--color-text-variant);
  text-decoration: none;
}
.badge-text--accent { color: var(--color-coral); }
a.badge-text:hover { text-decoration: underline; }
.trace-note {
  margin-top: var(--stack-sm);
  font-size: 13px;
  line-height: 20px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.trace-note a { color: var(--color-primary); }

/* ---------- Cards ---------- */
.card {
  display: flex;
  flex-direction: column;
  height: 100%;
  background: var(--color-surface);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: 24px;
}
.card h3 {
  font-size: 24px;
  line-height: 32px;
  margin-bottom: 8px;
}
.data-list {
  list-style: none;
  padding: 12px 16px;
  margin-top: var(--stack-md);
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 500;
  color: var(--color-primary);
}
.data-list li {
  display: flex;
  justify-content: space-between;
  padding: 8px 0;
  border-bottom: 1px solid var(--color-border-light);
}
.data-list li:last-child { border-bottom: none; }

/* ---------- Callout ---------- */
.callout {
  background: var(--color-bg-highest);
  border-left: 4px solid var(--color-accent-strong);
  border-radius: var(--radius-sm);
  padding: 24px;
}
.callout--muted {
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border-light);
  border-left: 4px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 24px;
}

/* ---------- Comparison table ---------- */
.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
}
.compare-table {
  width: 100%;
  min-width: 800px;
  table-layout: fixed;
  border-collapse: collapse;
  text-align: left;
}
.compare-table thead {
  background: var(--color-bg);
  position: sticky;
  top: 0;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.02);
}
.compare-table th {
  padding: 16px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  border-bottom: 1px solid var(--color-border-light);
  border-left: 1px solid var(--color-border-light);
}
.compare-table th:first-child { border-left: none; width: 192px; }
.compare-table th.is-featured { color: var(--color-primary); }
.compare-table td {
  padding: 16px;
  border-left: 1px solid var(--color-border-light);
  font-size: 14px;
  color: var(--color-text-variant);
}
.compare-table td:first-child { border-left: none; color: var(--color-text); }
.compare-table tbody tr { border-bottom: 1px solid var(--color-border-light); }
.compare-table tbody tr:nth-child(even) { background: rgba(216, 227, 250, 0.2); }
.compare-table .cell-strong { color: var(--color-text); font-weight: 700; }
.icon-yes { display: inline-flex; align-items: center; gap: 4px; color: var(--color-success); }

/* ---------- Page intro (inner pages) ---------- */
.page-intro {
  padding-top: var(--stack-lg);
  padding-bottom: var(--section-gap-mobile);
}
@media (min-width: 768px) {
  .page-intro { padding-bottom: var(--section-gap); }
}
.page-intro h1 {
  font-size: 32px;
  line-height: 40px;
  letter-spacing: -0.01em;
  margin: var(--stack-sm) 0 var(--stack-md);
}
@media (min-width: 768px) {
  .page-intro h1 { font-size: 48px; line-height: 56px; letter-spacing: -0.02em; }
}

.policy-block {
  border-top: 1px solid var(--color-border-light);
  padding-top: var(--stack-lg);
}
.policy-block + .policy-block { margin-top: var(--stack-lg); }
.policy-block h2 { font-size: 24px; line-height: 32px; margin-bottom: var(--stack-sm); }

/* ---------- Author box ---------- */
.author-box {
  display: flex;
  align-items: center;
  gap: 16px;
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-sm);
  padding: 24px;
  background: var(--color-surface);
}
.author-box__avatar {
  width: 56px;
  height: 56px;
  border-radius: 999px;
  background: var(--color-bg-highest);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-variant);
  flex-shrink: 0;
}
.author-box__name { font-weight: 700; }
.author-box__meta { font-size: 14px; color: var(--color-text-variant); }
.author-box--detailed { align-items: flex-start; }
.author-box__detail { margin-top: var(--stack-sm); font-size: 14px; color: var(--color-text-variant); }
.author-box__detail + .text-link { margin-top: var(--stack-sm); display: inline-block; }

/* ---------- FAQ ---------- */
.faq-list { display: flex; flex-direction: column; gap: 12px; }
.faq-item {
  background: var(--color-surface);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-sm);
  padding: 16px;
}
.faq-item summary {
  font-size: 18px;
  line-height: 28px;
  font-weight: 700;
  cursor: pointer;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary .material-symbols-outlined { transition: transform 0.2s ease; flex-shrink: 0; color: var(--color-text-variant); }
.faq-item[open] summary .material-symbols-outlined { transform: rotate(180deg); }
.faq-item p { margin-top: var(--stack-sm); color: var(--color-text-variant); }

/* ---------- Grids ---------- */
.grid-2 { display: grid; grid-template-columns: 1fr; align-items: stretch; gap: var(--stack-lg); }
.grid-3 { display: grid; grid-template-columns: 1fr; align-items: stretch; gap: var(--gutter); }
.grid-4 { display: grid; grid-template-columns: 1fr; align-items: stretch; gap: var(--gutter); }
@media (min-width: 768px) {
  .grid-2 { grid-template-columns: 1fr 1fr; }
  .grid-3 { grid-template-columns: repeat(3, 1fr); }
  .grid-4 { grid-template-columns: repeat(4, 1fr); }
}

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--color-border-light);
  background: var(--color-bg-container);
  padding: var(--section-gap-mobile) 0;
}
@media (min-width: 768px) {
  .site-footer { padding: var(--section-gap) 0; }
}
.site-footer__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--gutter);
}
@media (min-width: 768px) {
  .site-footer__grid { grid-template-columns: 1fr 1fr 1fr; }
}
.site-footer__logo {
  font-family: var(--font-display);
  font-size: 24px;
  font-weight: 700;
}
.site-footer__copy {
  margin-top: var(--stack-md);
  max-width: 360px;
  font-size: 14px;
  color: var(--color-text-variant);
}
.site-footer__copy a { color: var(--color-text-variant); text-decoration: underline; }
.site-footer__col h4 {
  font-family: var(--font-body);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  margin-bottom: var(--stack-md);
}
.site-footer__col ul { list-style: none; display: flex; flex-direction: column; gap: 12px; }
.site-footer__col a { color: var(--color-text-variant); text-decoration: none; }
.site-footer__col a:hover { text-decoration: underline; color: var(--color-text); }