/* ── MAILSTACK — SHARED STYLES ── */
@import url('https://fonts.googleapis.com/css2?family=Syne:wght@400;600;700;800&family=JetBrains+Mono:wght@300;400;500&display=swap');

:root {
  --bg: #080a0f;
  --bg2: #0d1117;
  --surface: #161c28;
  --border: rgba(255,255,255,0.07);
  --accent: #00e5ff;
  --accent2: #7b61ff;
  --accent3: #00ff88;
  --text: #e8eaf0;
  --muted: #5a6278;
  --heading: #ffffff;
  --font-head: 'Syne', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 15px;
  line-height: 1.7;
  overflow-x: hidden;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)' opacity='0.04'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: 1000;
  opacity: 0.5;
}

/* ── NAV ── */
nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 60px;
  border-bottom: 1px solid var(--border);
  background: rgba(8,10,15,0.9);
  backdrop-filter: blur(20px);
  transition: padding 0.3s;
}

.logo { text-decoration: none; }
.logo svg { display: block; }

.nav-links {
  display: flex;
  gap: 32px;
  list-style: none;
}
.nav-links a {
  color: var(--muted);
  text-decoration: none;
  font-size: 12px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  transition: color 0.2s;
  position: relative;
}
.nav-links a:hover,
.nav-links a.active { color: var(--accent); }
.nav-links a.active::after {
  content: '';
  position: absolute;
  bottom: -4px; left: 0; right: 0;
  height: 1px;
  background: var(--accent);
}

.nav-cta {
  background: transparent;
  border: 1px solid var(--accent);
  color: var(--accent);
  padding: 8px 20px;
  font-family: var(--font-mono);
  font-size: 12px;
  cursor: pointer;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  transition: all 0.25s;
  text-decoration: none;
}
.nav-cta:hover { background: var(--accent); color: var(--bg); }

/* ── HAMBURGER ── */
.nav-burger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  background: none;
  border: none;
  padding: 4px;
}
.nav-burger span {
  display: block;
  width: 22px;
  height: 1.5px;
  background: var(--text);
  transition: all 0.3s;
}

/* ── PAGE HEADER ── */
.page-header {
  padding: 160px 60px 80px;
  position: relative;
  overflow: hidden;
  border-bottom: 1px solid var(--border);
}
.page-header-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(0,229,255,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0,229,255,0.03) 1px, transparent 1px);
  background-size: 60px 60px;
  mask-image: radial-gradient(ellipse 80% 80% at 30% 50%, black 30%, transparent 100%);
}
.page-header-glow {
  position: absolute;
  width: 500px; height: 500px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(0,229,255,0.07) 0%, transparent 70%);
  top: -100px; right: -50px;
  pointer-events: none;
}
.page-header-content { position: relative; max-width: 700px; }

/* ── TYPOGRAPHY ── */
h1 {
  font-family: var(--font-head);
  font-size: clamp(40px, 5.5vw, 72px);
  font-weight: 800;
  color: var(--heading);
  line-height: 1.0;
  letter-spacing: -2px;
  margin-bottom: 24px;
}
h1 em { font-style: normal; color: transparent; -webkit-text-stroke: 1px var(--accent); }

h2 {
  font-family: var(--font-head);
  font-size: clamp(28px, 3.5vw, 48px);
  font-weight: 800;
  color: var(--heading);
  letter-spacing: -1.5px;
  line-height: 1.05;
  margin-bottom: 16px;
}
h2 em { font-style: normal; color: var(--accent); }

h3 {
  font-family: var(--font-head);
  font-size: 22px;
  font-weight: 700;
  color: var(--heading);
  letter-spacing: -0.5px;
  margin-bottom: 12px;
}

.section-label {
  font-size: 11px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 12px;
}
.section-label::before {
  content: '';
  width: 28px; height: 1px;
  background: var(--accent);
}

.section-desc {
  color: var(--muted);
  max-width: 520px;
  margin-bottom: 56px;
  font-size: 15px;
  line-height: 1.8;
}

/* ── BUTTONS ── */
.btn-primary {
  background: var(--accent);
  color: var(--bg);
  border: none;
  padding: 14px 32px;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.05em;
  cursor: pointer;
  text-decoration: none;
  display: inline-block;
  transition: all 0.25s;
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 10px 35px rgba(0,229,255,0.25); }

.btn-ghost {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
  padding: 14px 32px;
  font-family: var(--font-mono);
  font-size: 13px;
  cursor: pointer;
  text-decoration: none;
  display: inline-block;
  transition: all 0.25s;
  letter-spacing: 0.05em;
}
.btn-ghost:hover { border-color: var(--muted); color: var(--heading); }

/* ── SECTIONS ── */
section { padding: 60px 60px; }
.section-dark { background: var(--bg2); }

/* ── CARDS ── */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
}
.card {
  background: var(--bg);
  padding: 36px;
  transition: background 0.25s;
  position: relative;
  overflow: hidden;
}
.card::after {
  content: '';
  position: absolute;
  bottom: 0; left: 0; right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--accent), var(--accent2));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.35s ease;
}
.card:hover { background: var(--surface); }
.card:hover::after { transform: scaleX(1); }

/* ── REVEAL ── */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.reveal.visible { opacity: 1; transform: translateY(0); }

/* ── FOOTER ── */
footer {
  background: var(--bg2);
  border-top: 1px solid var(--border);
}
.footer-main {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: 48px;
  padding: 64px 60px 48px;
}
.footer-brand-desc {
  font-size: 13px;
  color: var(--muted);
  line-height: 1.7;
  margin-top: 16px;
  max-width: 260px;
}
.footer-col-title {
  font-size: 11px;
  color: var(--heading);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  margin-bottom: 20px;
}
.footer-links-list { list-style: none; display: flex; flex-direction: column; gap: 10px; }
.footer-links-list a {
  font-size: 13px;
  color: var(--muted);
  text-decoration: none;
  transition: color 0.2s;
}
.footer-links-list a:hover { color: var(--accent); }
.footer-bottom {
  border-top: 1px solid var(--border);
  padding: 20px 60px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 12px;
  color: var(--muted);
}
.footer-bottom a { color: var(--muted); text-decoration: none; }
.footer-bottom a:hover { color: var(--accent); }

/* ── MOBILE ── */
@media (max-width: 900px) {
  nav { padding: 16px 24px !important; }
  .nav-links, .nav-cta { display: none; }
  .nav-burger { display: flex; }
  nav.menu-open .nav-links {
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 61px; left: 0; right: 0;
    background: var(--bg2);
    border-bottom: 1px solid var(--border);
    padding: 24px;
    gap: 20px;
    z-index: 200;
  }
  nav.menu-open .nav-cta {
    display: inline-block;
    position: fixed;
    top: calc(61px + var(--menu-items, 280px));
    left: 24px; right: 24px;
    z-index: 200;
    text-align: center;
  }
  section { padding: 40px 24px !important; }
  .page-header { padding: 120px 24px 60px !important; }
  .cards-grid { grid-template-columns: 1fr !important; }
  .footer-main { grid-template-columns: 1fr 1fr !important; gap: 32px !important; padding: 48px 24px 32px !important; }
  .footer-bottom { flex-direction: column; gap: 8px; text-align: center; padding: 20px 24px !important; }

  /* Force inline-styled grids to collapse */
  [style*="grid-template-columns: repeat(3"] { grid-template-columns: 1fr !important; }
  [style*="grid-template-columns:repeat(3"] { grid-template-columns: 1fr !important; }
  [style*="grid-template-columns: repeat(4"] { grid-template-columns: 1fr 1fr !important; }
  [style*="grid-template-columns:repeat(4"] { grid-template-columns: 1fr 1fr !important; }
  [style*="grid-template-columns: 2fr 1fr 1fr 1fr"] { grid-template-columns: 1fr 1fr !important; }
  [style*="grid-template-columns:2fr 1fr 1fr 1fr"] { grid-template-columns: 1fr 1fr !important; }
  [style*="grid-template-columns: 1fr 340px"] { grid-template-columns: 1fr !important; }
  [style*="grid-template-columns:1fr 340px"] { grid-template-columns: 1fr !important; }
  [style*="grid-template-columns: 1fr 320px"] { grid-template-columns: 1fr !important; }
  [style*="grid-template-columns:1fr 320px"] { grid-template-columns: 1fr !important; }
  [style*="grid-template-columns: 220px 1fr"] { grid-template-columns: 1fr !important; }
  [style*="grid-template-columns:220px 1fr"] { grid-template-columns: 1fr !important; }

  /* Force inline paddings to mobile-friendly values */
  [style*="padding:60px 60px"],
  [style*="padding: 60px 60px"],
  [style*="padding:60px 60px"],
  [style*="padding:120px 60px"],
  [style*="padding: 120px 60px"] { padding: 40px 24px !important; }
  [style*="padding:40px 60px"],
  [style*="padding: 40px 60px"] { padding: 32px 24px !important; }
  [style*="padding:80px 60px"],
  [style*="padding: 80px 60px"] { padding: 48px 24px !important; }
  [style*="padding:20px 60px"],
  [style*="padding: 20px 60px"] { padding: 16px 24px !important; }
  [style*="padding:0 60px"],
  [style*="padding: 0 60px"] { padding: 0 24px !important; }

  /* Two-column inline forms */
  [style*="grid-template-columns: 1fr 1fr"],
  [style*="grid-template-columns:1fr 1fr"] { grid-template-columns: 1fr !important; }

  /* Tables on mobile */
  table { display: block; overflow-x: auto; -webkit-overflow-scrolling: touch; }

  /* Flex wrapping */
  .section-tabs { flex-wrap: wrap !important; }
}

@media (max-width: 600px) {
  .footer-main { grid-template-columns: 1fr !important; gap: 24px !important; }
  .cards-grid { gap: 0 !important; }
  h1 { font-size: clamp(32px, 8vw, 44px) !important; letter-spacing: -1px !important; }
  h2 { font-size: clamp(24px, 6vw, 32px) !important; letter-spacing: -1px !important; }
  .btn-primary, .btn-ghost { padding: 12px 24px !important; font-size: 12px !important; }
  .section-desc { margin-bottom: 32px; }

  /* Course sidebar collapse */
  .course-sidebar { max-height: 180px !important; }
}

@media (max-width: 480px) {
  nav { padding: 12px 16px !important; }
  section { padding: 32px 16px !important; }
  .page-header { padding: 100px 16px 48px !important; }
  [style*="padding:60px 60px"],
  [style*="padding: 60px 60px"],
  [style*="padding:40px 60px"],
  [style*="padding: 40px 60px"],
  [style*="padding:120px 60px"],
  [style*="padding: 120px 60px"] { padding: 32px 16px !important; }
  [style*="padding:80px 60px"],
  [style*="padding: 80px 60px"] { padding: 32px 16px !important; }
  [style*="padding:20px 60px"],
  [style*="padding: 20px 60px"] { padding: 12px 16px !important; }
  [style*="padding:0 60px"],
  [style*="padding: 0 60px"] { padding: 0 16px !important; }
  .footer-main { padding: 32px 16px 24px !important; }
  .footer-bottom { padding: 16px !important; }

  /* All remaining multi-col grids to single */
  [style*="grid-template-columns: 1fr 1fr"],
  [style*="grid-template-columns:1fr 1fr"] { grid-template-columns: 1fr !important; }
  [style*="grid-template-columns: repeat(2"],
  [style*="grid-template-columns:repeat(2"] { grid-template-columns: 1fr !important; }
}


/* ── COURSE LAYOUT OVERRIDE ── */
.course-layout {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 0;
  min-height: 100vh;
  padding-top: 61px;
  align-items: start;
}
.course-sidebar {
  position: sticky;
  top: 61px;
  height: calc(100vh - 61px);
  overflow-y: auto;
  scrollbar-width: thin;
}
@media (max-width: 900px) {
  .course-layout {
    grid-template-columns: 1fr;
  }
  .course-sidebar {
    position: static;
    height: auto;
    max-height: 260px;
    overflow-y: auto;
    border-bottom: 1px solid var(--border);
  }
  .course-content { padding: 24px 16px; }
}