/* shared.css — Sun Zu Lab website · Inspired by sunzulab.com */

/* ============================
   RESET & BASE
============================ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: auto; font-size: 16px; }
body {
  font-family: 'DM Mono', monospace;
  background: #0B0B10;
  color: rgba(255,255,255,0.5);
  font-weight: 300;
  line-height: 1.7;
  overflow-x: hidden;
}
img { max-width: 100%; display: block; }
a { text-decoration: none; color: inherit; }

/* ============================
   CSS VARIABLES
============================ */
:root {
  --bg:         #0B0B10;
  --bg-nav:     rgba(15,15,20,0.9);
  --bg-card:    rgba(255,255,255,0.03);
  --bg-card2:   rgba(255,255,255,0.05);
  --accent:     #9EB8FF;
  --accent-dim: rgba(158,184,255,0.1);
  --accent-border: rgba(158,184,255,0.15);
  --white:      #FFFFFF;
  --text:       rgba(255,255,255,0.5);
  --text-muted: rgba(255,255,255,0.3);
  --border:     rgba(255,255,255,0.06);
  --radius:     12px;
  --radius-sm:  8px;
  --transition: 0.25s ease;
}

/* ============================
   TYPOGRAPHY
============================ */
h1, h2, h3 {
  font-family: 'Cormorant Garamond', serif;
  color: var(--white);
  font-weight: 300;
  line-height: 1.1;
  letter-spacing: -0.02em;
}
h1 { font-size: clamp(3rem, 6vw, 6rem); }
h2 { font-size: clamp(2rem, 4vw, 3.5rem); }
h3 { font-size: clamp(1.2rem, 2vw, 1.6rem); font-weight: 400; }
h1 em, h2 em, h3 em {
  font-style: italic;
  color: var(--accent);
}
p { font-size: 1rem; color: var(--text); font-weight: 300; }

.mono { font-family: 'DM Mono', monospace; }
.accent { color: var(--accent); }

.tag {
  display: inline-block;
  font-family: 'DM Mono', monospace;
  font-size: 0.7rem;
  font-weight: 400;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: 6px 14px;
  border-radius: 100px;
  background: var(--accent-dim);
  color: var(--accent);
  border: 1px solid var(--accent-border);
  margin-bottom: 1.5rem;
}

/* ============================
   LAYOUT
============================ */
.container { max-width: 1160px; margin: 0 auto; padding: 0 32px; }
.section { padding: 120px 0; }
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.text-center { text-align: center; }

.section-head { margin-bottom: 64px; }
.section-head.center { text-align: center; }
.section-head.center p { margin: 0 auto; max-width: 560px; }
.section-head h2 { margin: 16px 0 20px; }
.section-head p { max-width: 560px; }

.divider {
  width: 48px; height: 1px;
  background: var(--accent);
  opacity: 0.4;
  margin: 16px 0;
}
.divider.center { margin: 16px auto; }

/* ============================
   BUTTONS
============================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 28px;
  border-radius: var(--radius-sm);
  font-family: 'Syne', sans-serif;
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  cursor: pointer;
  transition: all var(--transition);
  border: none;
}
.btn-primary {
  background: var(--white);
  color: var(--bg);
}
.btn-primary:hover {
  background: rgba(255,255,255,0.85);
  transform: translateY(-1px);
  box-shadow: 0 8px 32px rgba(255,255,255,0.1);
}
.btn-outline {
  background: transparent;
  color: var(--white);
  border: 1px solid rgba(255,255,255,0.2);
}
.btn-outline:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-dim);
}
.btn-lg { padding: 16px 36px; font-size: 0.9rem; }
.btn-accent {
  background: var(--accent);
  color: var(--bg);
}
.btn-accent:hover {
  background: #b3c8ff;
  transform: translateY(-1px);
}
.hero-ctas { display: flex; gap: 14px; flex-wrap: wrap; }
.cta-buttons { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

/* ============================
   CARDS
============================ */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  transition: border-color var(--transition), transform var(--transition);
}
.card:hover {
  border-color: var(--accent-border);
  transform: translateY(-2px);
}

/* ============================
   NAVIGATION
============================ */
nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  transition: background 0.3s, box-shadow 0.3s;
}
nav.scrolled {
  background: var(--bg-nav);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  box-shadow: 0 1px 0 var(--border);
}
.nav-inner {
  max-width: 1160px;
  margin: 0 auto;
  padding: 0 32px;
  height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-logo {
  font-family: 'Syne', sans-serif;
  font-size: 1.1rem;
  font-weight: 800;
  color: var(--white);
  letter-spacing: 0.06em;
}
.nav-logo span { font-weight: 400; opacity: 0.6; }
.nav-links {
  display: flex;
  align-items: center;
  gap: 36px;
  list-style: none;
}
.nav-links a {
  font-family: 'DM Mono', monospace;
  font-size: 0.8rem;
  font-weight: 400;
  color: rgba(255,255,255,0.5);
  transition: color var(--transition);
}
.nav-links a:hover, .nav-links a.active { color: var(--white); }
.nav-cta { margin-left: 8px; }

.nav-mobile-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
  flex-direction: column;
  gap: 5px;
}
.nav-mobile-toggle span {
  display: block;
  width: 22px;
  height: 1.5px;
  background: var(--white);
  border-radius: 2px;
}

/* ============================
   NAV DROPDOWN
============================ */
.nav-dropdown { position: relative; }
.nav-dropdown > a { display: flex; align-items: center; gap: 4px; }
.nav-dropdown > a::after {
  content: '';
  width: 0; height: 0;
  border-left: 3px solid transparent;
  border-right: 3px solid transparent;
  border-top: 3px solid rgba(255,255,255,0.3);
  transition: transform var(--transition);
}
.nav-dropdown:hover > a::after { transform: rotate(180deg); }
.nav-dropdown-menu {
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  padding-top: 14px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s;
}
.nav-dropdown:hover .nav-dropdown-menu { opacity: 1; pointer-events: auto; }
.nav-dropdown-inner {
  background: rgba(15,15,20,0.98);
  backdrop-filter: blur(20px);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 8px;
  min-width: 280px;
  box-shadow: 0 16px 48px rgba(0,0,0,0.5);
}
.nav-dropdown-item {
  display: block;
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  transition: background var(--transition);
}
.nav-dropdown-item:hover { background: rgba(158,184,255,0.06); }
.nav-dropdown-item strong {
  display: block;
  font-family: 'Syne', sans-serif;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--white);
  margin-bottom: 2px;
}
.nav-dropdown-item span { font-size: 0.7rem; color: var(--text-muted); }

/* ============================
   PAGE HERO (sub-pages)
============================ */
.page-hero {
  padding: 160px 0 96px;
  position: relative;
  overflow: hidden;
  text-align: center;
}
.page-hero .container { position: relative; z-index: 1; }
.page-hero h1 { margin: 16px 0 24px; }
.page-hero p { color: var(--text); max-width: 560px; font-size: 1.1rem; margin: 0 auto; }

/* ============================
   FOOTER
============================ */
footer {
  padding: 48px 0;
  border-top: 1px solid var(--border);
}
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 24px;
}
.footer-logo {
  font-family: 'Syne', sans-serif;
  font-size: 1rem;
  font-weight: 800;
  color: var(--white);
  letter-spacing: 0.06em;
}
.footer-logo span { font-weight: 400; opacity: 0.6; }
.footer-links { display: flex; gap: 24px; list-style: none; }
.footer-links a {
  font-size: 0.8rem;
  color: var(--text-muted);
  transition: color var(--transition);
}
.footer-links a:hover { color: var(--white); }
.footer-copy { font-size: 0.75rem; color: var(--text-muted); }

/* ============================
   SCROLL REVEAL
============================ */
.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============================
   RESPONSIVE
============================ */
@media (max-width: 900px) {
  .grid-2, .grid-3 { grid-template-columns: 1fr 1fr; }
  .section { padding: 80px 0; }
}
@media (max-width: 640px) {
  .section { padding: 64px 0; }
  .grid-2, .grid-3 { grid-template-columns: 1fr; }
  .nav-links {
    display: none;
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(11,11,16,0.97);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 32px;
    z-index: 200;
    padding: 80px 32px;
  }
  .nav-links.open { display: flex; }
  .nav-links a {
    font-size: 1.2rem;
    color: rgba(255,255,255,0.6);
  }
  .nav-links a:hover, .nav-links a.active { color: var(--white); }
  .nav-cta { display: none; }
  .nav-links.open ~ .nav-cta { display: none; }
  .nav-mobile-toggle { display: flex; z-index: 201; position: relative; }
  .nav-mobile-toggle.open span:nth-child(1) { transform: rotate(45deg) translate(4px, 4px); }
  .nav-mobile-toggle.open span:nth-child(2) { opacity: 0; }
  .nav-mobile-toggle.open span:nth-child(3) { transform: rotate(-45deg) translate(4px, -4px); }
  .nav-mobile-toggle span { transition: transform 0.3s, opacity 0.3s; }
  /* Hide dropdown submenu on mobile — show links inline */
  .nav-dropdown-menu { display: none; }
  .nav-dropdown > a::after { display: none; }
  h1 { font-size: clamp(2.4rem, 8vw, 3.5rem); }
}