/* Shared styles for all root pages (homepage, contact, privacy, terms) */

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

:root {
  --black: #0a0a0a;
  --white: #ffffff;
  --g1: #f7f7f6;
  --g2: #e8e8e6;
  --g3: #c7c7c3;
  --g4: #8f8f8b;
  --g5: #4a4a47;
  --font-h: "Syne", "Noto Serif TC", sans-serif;
  --font-b: "DM Sans", "Noto Sans TC", sans-serif;
  --font-m: "JetBrains Mono", "Noto Sans TC", monospace;
}

[data-theme="dark"] {
  --black: #efefed;
  --white: #111110;
  --g1: #1c1c1a;
  --g2: #2c2c2a;
  --g3: #3d3d3b;
  --g4: #888884;
  --g5: #aeaead;
}

html { height: 100%; scroll-behavior: smooth; }

body {
  font-family: var(--font-b);
  background: var(--white);
  color: var(--black);
  font-size: 14px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  min-height: 100%;
  display: flex;
  flex-direction: column;
}

a { color: inherit; text-decoration: none; }

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

header {
  position: sticky;
  top: 0;
  z-index: 200;
  background: var(--white);
  border-bottom: 1px solid var(--g2);
  padding: 0 40px;
  height: 56px;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  transition: background 0.2s;
}

.logo-link { display: flex; align-items: center; flex-shrink: 0; }
.logo-img { height: 24px; display: block; }
[data-theme="dark"] .logo-img { filter: invert(1); }

.main-nav { display: flex; align-items: center; gap: 28px; }
.main-nav a {
  font-family: var(--font-m);
  font-size: 10px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--g4);
  transition: color 0.15s;
}
.main-nav a:hover, .main-nav a.active { color: var(--black); }

.header-controls { display: flex; align-items: center; gap: 12px; justify-self: end; grid-column: 3; }

.theme-toggle {
  background: none;
  border: none;
  cursor: pointer;
  color: var(--g4);
  display: flex;
  align-items: center;
  padding: 4px;
  border-radius: 4px;
  transition: color 0.15s;
}
.theme-toggle:hover { color: var(--black); }
.icon-sun { display: none; }

.pill-group {
  display: flex;
  background: var(--g1);
  border-radius: 100px;
  padding: 2px;
  gap: 2px;
}
.pill-group button {
  background: none;
  border: none;
  cursor: pointer;
  font-family: var(--font-m);
  font-size: 10px;
  letter-spacing: 0.06em;
  color: var(--g4);
  padding: 4px 10px;
  border-radius: 100px;
  transition: background 0.15s, color 0.15s;
  white-space: nowrap;
}
.pill-group button.active {
  background: var(--white);
  color: var(--black);
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
}

/* ---- Main ---- */

main { flex: 1; }

/* ---- Footer ---- */

footer {
  border-top: 1px solid var(--g2);
  padding: 20px 40px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.footer-copy {
  font-family: var(--font-m);
  font-size: 10px;
  color: var(--g3);
  letter-spacing: 0.04em;
}

.footer-nav { display: flex; gap: 20px; }
.footer-nav a {
  font-family: var(--font-m);
  font-size: 10px;
  color: var(--g3);
  letter-spacing: 0.04em;
  transition: color 0.15s;
}
.footer-nav a:hover { color: var(--black); }

/* ---- Shared components ---- */

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-m);
  font-size: 10px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--g4);
  margin-bottom: 40px;
  transition: color 0.15s;
}
.back-link:hover { color: var(--black); }

.eyebrow {
  font-family: var(--font-m);
  font-size: 10px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--g4);
  margin-bottom: 12px;
}

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

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--black);
  color: var(--white);
  font-family: var(--font-m);
  font-size: 10px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 12px 24px;
  border-radius: 4px;
  border: none;
  cursor: pointer;
  transition: opacity 0.15s, transform 0.15s;
}
.btn-primary:hover { opacity: 0.85; transform: translateY(-1px); }

.btn-secondary {
  display: inline-flex;
  align-items: center;
  font-family: var(--font-m);
  font-size: 10px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--g5);
  padding: 12px 24px;
  border: 1px solid var(--g2);
  border-radius: 4px;
  cursor: pointer;
  background: none;
  transition: border-color 0.15s, color 0.15s, transform 0.15s;
}
.btn-secondary:hover { border-color: var(--g4); color: var(--black); transform: translateY(-1px); }

/* ---- Prose (legal pages) ---- */

.prose { display: flex; flex-direction: column; gap: 32px; }
.prose h2 { font-family: var(--font-h); font-size: 1rem; font-weight: 700; margin-bottom: 8px; }
.prose p { color: var(--g5); line-height: 1.75; }
.prose a { text-decoration: underline; text-underline-offset: 3px; text-decoration-color: var(--g2); transition: text-decoration-color 0.15s; }
.prose a:hover { text-decoration-color: var(--black); }

/* ---- Mobile menu ---- */

.hamburger-btn {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px 4px;
  -webkit-tap-highlight-color: transparent;
}
.hamburger-btn span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--black);
  border-radius: 2px;
}
[data-theme="dark"] .hamburger-btn span { background: var(--black); }

.mobile-menu {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 300;
  background: rgba(10, 10, 10, 0.4);
}
.mobile-menu.open { display: block; }
.mobile-menu-inner {
  position: absolute;
  right: 0;
  top: 0;
  bottom: 0;
  width: 260px;
  max-width: 85vw;
  background: var(--white);
  padding: 0 28px 32px;
  display: flex;
  flex-direction: column;
  overflow-y: auto;
}
[data-theme="dark"] .mobile-menu-inner {
  background: #111;
  border-left: 1px solid var(--g5);
}
.mobile-menu-close {
  align-self: flex-end;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--g4);
  font-size: 20px;
  height: 52px;
  display: flex;
  align-items: center;
  -webkit-tap-highlight-color: transparent;
}
.mobile-menu nav {
  display: flex;
  flex-direction: column;
}
.mobile-menu nav a {
  font-family: var(--font-m);
  font-size: 11px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--g4);
  padding: 18px 0;
  border-bottom: 1px solid var(--g2);
  transition: color 0.15s;
}
.mobile-menu nav a:last-child { border-bottom: none; }
.mobile-menu nav a.active { color: var(--black); }
[data-theme="dark"] .mobile-menu nav a.active,
[data-theme="dark"] .mobile-menu nav a:hover { color: var(--white); }

/* ---- Responsive ---- */

@media (max-width: 640px) {
  header { padding: 0 20px; height: 52px; }
  .main-nav { display: none; }
  /* 3-column layout: logo (1fr) | theme+lang (auto, center) | hamburger (1fr, far right) */
  .header-controls { grid-column: 2; grid-row: 1; justify-self: center; }
  .hamburger-btn { display: flex; grid-column: 3; grid-row: 1; justify-self: end; }
  footer { padding: 16px 20px; }
}

@media (max-width: 400px) {
  .pill-group button { padding: 4px 8px; }
}

/* ---- Mobile menu language section ---- */

.mobile-menu-lang {
  margin-top: auto;
  padding-top: 28px;
  border-top: 1px solid var(--g2);
}
.mobile-menu-lang .pill-group {
  display: flex;
  width: fit-content;
}
[data-theme="dark"] .mobile-menu-lang .pill-group {
  background: var(--g2);
}
[data-theme="dark"] .mobile-menu-lang .pill-group button.active {
  background: var(--g3);
  color: var(--black);
}