:root {
  --bg: #0b1020;
  --bg-alt: #121a33;
  --card: #161f3d;
  --accent: #5eead4;
  --accent-2: #818cf8;
  --text: #e6e9f5;
  --muted: #9aa3c4;
  --border: #263159;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}
h1 { font-size: 2rem; font-weight: 800; margin-bottom: 12px; letter-spacing: -0.01em; }
h2 { font-size: 1.3rem; font-weight: 700; margin: 32px 0 16px; }
a { color: var(--accent); }
.muted { color: var(--muted); }

.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(11,16,32,0.9);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}
.site-header nav {
  max-width: 1000px; margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
  padding: 16px 24px;
}
.logo {
  display: flex; align-items: center; gap: 10px;
  font-weight: 700; font-size: 1.15rem; color: var(--text); text-decoration: none;
}
.logo-mark {
  width: 30px; height: 30px; border-radius: 8px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  display: flex; align-items: center; justify-content: center;
  font-size: 0.95rem; color: #0b1020; font-weight: 800;
}
.nav-links { display: flex; gap: 22px; list-style: none; align-items: center; }
.nav-links a { color: var(--muted); text-decoration: none; font-size: 0.92rem; }
.nav-links a:hover { color: var(--text); }
.nav-cta {
  padding: 8px 16px; border-radius: 8px;
  background: var(--accent) !important; color: #0b1020 !important;
  font-weight: 600;
}

.site-main { max-width: 900px; margin: 0 auto; padding: 48px 24px 80px; }
.site-footer { text-align: center; padding: 30px 24px; color: var(--muted); font-size: 0.82rem; border-top: 1px solid var(--border); }

.auth-card {
  max-width: 400px; margin: 40px auto; background: var(--card);
  border: 1px solid var(--border); border-radius: 14px; padding: 32px;
}
.auth-card form { display: flex; flex-direction: column; gap: 16px; margin-top: 20px; }
.auth-card label { display: flex; flex-direction: column; gap: 6px; font-size: 0.85rem; color: var(--muted); }
.auth-card input {
  padding: 11px 14px; border-radius: 8px; border: 1px solid var(--border);
  background: var(--bg-alt); color: var(--text); font-size: 0.95rem; outline: none;
}
.auth-card input:focus { border-color: var(--accent); }
.form-error { color: #fca5a5; font-size: 0.88rem; margin-top: 10px; }
.fine-print { color: var(--muted); font-size: 0.82rem; margin-top: 18px; }

.btn-primary, .btn-secondary {
  padding: 11px 22px; border-radius: 9px; font-weight: 600; font-size: 0.9rem;
  text-decoration: none; display: inline-block; border: 1px solid transparent;
  cursor: pointer; transition: opacity 0.2s, border-color 0.2s;
}
.btn-primary { background: var(--accent); color: #0b1020; }
.btn-primary:hover { opacity: 0.88; }
.btn-secondary { background: transparent; color: var(--text); border-color: var(--border); }
.btn-secondary:hover { border-color: var(--accent); color: var(--accent); }

.course-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 20px; margin-bottom: 12px; }
.course-card {
  background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 22px;
}
.course-card h3 { font-size: 1.05rem; margin-bottom: 10px; }
.course-card form { margin-top: 4px; }

.progress-bar { height: 8px; border-radius: 999px; background: var(--bg-alt); overflow: hidden; margin: 10px 0; }
.progress-fill { height: 100%; background: linear-gradient(90deg, var(--accent), var(--accent-2)); }

.plain-list { list-style: none; margin-bottom: 8px; }
.plain-list li { padding: 10px 0; border-bottom: 1px solid var(--border); }
.plain-list a { text-decoration: none; }
.plain-list a:hover { text-decoration: underline; }

.quiz-question { background: var(--card); border: 1px solid var(--border); border-radius: 10px; padding: 18px; margin-bottom: 14px; }
.quiz-option { display: block; padding: 8px 0; font-size: 0.92rem; cursor: pointer; }

.notice-card {
  background: rgba(129,140,248,0.08); border: 1px solid rgba(129,140,248,0.25);
  border-radius: 10px; padding: 18px; margin: 20px 0; font-size: 0.88rem;
}
.notice-card p { margin-bottom: 8px; }
.notice-card p:last-child { margin-bottom: 0; }
.notice-card code { background: var(--bg-alt); padding: 2px 6px; border-radius: 4px; font-size: 0.85em; }