/* Repend — shared design system */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  /* NASA Mars exploration palette — shared by platform UI and generated labs */
  --void: #050508;
  --bg0: #0c0c14;
  --bg1: #12121f;
  --bg2: #1a1a2e;
  --surface: rgba(255, 255, 255, 0.04);
  --surface2: rgba(255, 255, 255, 0.07);
  --glass: rgba(10, 15, 30, 0.75);
  --border: rgba(255, 255, 255, 0.09);
  --border-mars: rgba(232, 93, 4, 0.25);
  --text: #f4f4f8;
  --muted: #8899bb;
  --mars: #e85d04;
  --mars2: #c44a00;
  --dust: #8b4513;
  --ice: #4cc9f0;
  --copper: #d4a574;
  --accent: var(--mars);
  --accent2: var(--mars2);
  --teal: var(--ice);
  --amber: #fbbf24;
  --green: #22c55e;
  --r: 14px;
  --r-lg: 22px;
}

html { scroll-behavior: smooth; }

body {
  font-family: "Inter", -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg0);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background:
    radial-gradient(ellipse 70% 50% at 20% 10%, rgba(232, 93, 4, 0.1), transparent 55%),
    radial-gradient(ellipse 60% 45% at 85% 75%, rgba(76, 201, 240, 0.07), transparent 50%),
    linear-gradient(165deg, var(--void) 0%, var(--bg0) 45%, var(--bg1) 100%);
}

.page { position: relative; z-index: 1; }

/* Nav */
.site-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 40px;
  border-bottom: 1px solid var(--border);
  background: rgba(12, 12, 20, 0.75);
  backdrop-filter: blur(16px);
  position: sticky;
  top: 0;
  z-index: 100;
}

.site-logo {
  font-size: 1.35rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--text);
  text-decoration: none;
}

.site-logo b { color: var(--accent); font-weight: 800; }

.nav-links {
  display: flex;
  align-items: center;
  gap: 22px;
}

.nav-links a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.15s;
}

.nav-links a:hover,
.nav-links a.active { color: var(--text); }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: none;
  border-radius: 12px;
  font-family: inherit;
  font-weight: 600;
  cursor: pointer;
  text-decoration: none;
  transition: transform 0.15s, box-shadow 0.15s, background 0.15s;
}

.btn-primary {
  background: linear-gradient(135deg, var(--mars), var(--dust));
  color: #fff;
  padding: 12px 24px;
  font-size: 0.95rem;
  box-shadow: 0 4px 20px rgba(232, 93, 4, 0.25);
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 8px 28px rgba(232, 93, 4, 0.35);
}

.btn-lg {
  padding: 18px 40px;
  font-size: 1.1rem;
  border-radius: 16px;
}

.btn-outline {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 12px 24px;
  font-size: 0.95rem;
}

.btn-outline:hover { background: var(--surface2); }

.panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  backdrop-filter: blur(12px);
}

.section-label {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--teal);
  margin-bottom: 12px;
}

.section-title {
  font-size: clamp(1.75rem, 4vw, 2.4rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 16px;
}

.section-body {
  color: var(--muted);
  font-size: 1.05rem;
  line-height: 1.75;
  max-width: 56ch;
}

/* XP bar (learn page) */
.nav-xp-inner {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.72rem;
  color: var(--muted);
}

.nav-lvl { color: var(--accent); font-weight: 700; }

.nav-streak {
  font-size: 0.72rem;
  color: var(--mars);
  font-weight: 700;
}

.nav-xp-track {
  width: 72px;
  height: 5px;
  background: rgba(255,255,255,0.08);
  border-radius: 3px;
  overflow: hidden;
}

.nav-xp-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--teal));
  border-radius: 3px;
  transition: width 0.4s;
}

@media (max-width: 640px) {
  .site-nav { padding: 14px 20px; }
  .nav-links a:not(.btn) { display: none; }
}