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

/* Parametric colour system */

/* Site wide defaults */
:root {
  /* Main accent pair used in logo, buttons and hero */
  --accent-1: #22c55e;
  --accent-2: #0ea5e9;

  /* Hero gradient spots */
  --hero-spot-1: #0ea5e9;
  --hero-spot-2: #22c55e;

  /* Contact section gradient */
  --contact-1: #0f172a;
  --contact-2: #1f2937;
}

/* Per page theme override for the B-ASH-001 course page
   Use with body class "theme-course-bash001"
*/
body.theme-course-bash001 {
  --accent-1: #a855f7;
  --accent-2: #f97316;
  --hero-spot-1: #a855f7;
  --hero-spot-2: #f97316;
  --contact-1: #1e293b;
  --contact-2: #020617;
}

/* Per page theme override for a property themed page
   Use with body class "theme-property"
*/
body.theme-property {
  --accent-1: #22c55e;
  --accent-2: #16a34a;
  --hero-spot-1: #16a34a;
  --hero-spot-2: #22c55e;
  --contact-1: #064e3b;
  --contact-2: #022c22;
}

html {
  font-family: "Inter", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.6;
  color: #0f172a;
  background-color: #f8fafc;
}

body {
  margin: 0;
}

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

a {
  color: #0f766e;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* Layout helpers */

.container {
  width: min(1120px, 100% - 2.5rem);
  margin-inline: auto;
}

/* Header */

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background-color: rgba(15, 23, 42, 0.96);
  backdrop-filter: blur(16px);
  color: #e5e7eb;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-block: 0.75rem;
}

/* Logo */

.logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.logo-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.6rem;
  height: 2.6rem;
  border-radius: 999px;
  background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
  color: #0f172a;
  font-weight: 700;
}

.logo-text {
  display: flex;
  flex-direction: column;
}

.logo-name {
  font-weight: 600;
  font-size: 0.98rem;
}

.logo-tagline {
  font-size: 0.75rem;
  color: #9ca3af;
}

/* Navigation */

.main-nav {
  display: flex;
}

.main-nav ul {
  display: flex;
  list-style: none;
  gap: 1rem;
  margin: 0;
  padding: 0;
}

.main-nav li {
  position: relative;
}

/* Parent items that have a submenu */

.main-nav li.has-children > a::after {
  content: "▾";
  font-size: 0.7rem;
  margin-left: 0.25rem;
  opacity: 0.7;
}

/* Parent highlight on hover (desktop) */

.main-nav li:hover > a {
  background-color: rgba(148, 163, 184, 0.24);
  color: #f9fafb;
}

.main-nav a,
.main-nav a.nav-link {
  display: inline-flex;
  align-items: center;
  padding: 0.35rem 0.55rem;
  border-radius: 999px;
  font-size: 0.9rem;
  color: #e5e7eb;
  text-decoration: none;
  transition: background-color 0.15s ease, color 0.15s ease;
}

.main-nav a:hover,
.main-nav a.nav-link:hover {
  background-color: rgba(148, 163, 184, 0.24);
  color: #f9fafb;
}

/* Mobile nav toggle */

.nav-toggle {
  display: none;
  background: transparent;
  border: none;
  cursor: pointer;
}

.nav-toggle-bar {
  display: block;
  width: 20px;
  height: 2px;
  margin: 3px 0;
  background-color: #e5e7eb;
}

/* Submenu */

.submenu {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 12rem;
  padding: 0.4rem 0.2rem;
  margin: 0;
  list-style: none;
  background-color: #0f172a;
  border-radius: 0.85rem;
  box-shadow: 0 18px 35px rgba(15, 23, 42, 0.45);
  z-index: 40;
}

.submenu li a {
  display: block;
  padding: 0.4rem 0.8rem;
  border-radius: 0.6rem;
  font-size: 0.86rem;
  color: #e5e7eb;
  white-space: nowrap;
}

.submenu li a:hover {
  background-color: rgba(148, 163, 184, 0.32);
}

/* Show submenu on hover and focus (desktop)
   JS also toggles .submenu-open on li.has-children for finer control */

.main-nav li.has-children:hover > .submenu,
.main-nav li.has-children.submenu-open > .submenu,
.main-nav li.has-children:focus-within > .submenu {
  display: block;
}

/* Hero */

.hero {
  background: radial-gradient(circle at top left, var(--hero-spot-1) 0, transparent 55%),
    radial-gradient(circle at bottom right, var(--hero-spot-2) 0, transparent 60%);
  padding-block: 3