/* ========= RESET & VARIABLES ========= */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #0d0d14;
  --bg-card: #14141f;
  --bg-card2: #1c1c2e;
  --border: #252535;
  --text: #e8e8f0;
  --text-muted: #7878a0;
  --accent: #7c6af7;
  --accent-light: #a599ff;
  --accent-glow: rgba(124,106,247,0.18);
  --green: #3ecf8e;
  --red: #f04;
  --yellow: #f5a623;
  --radius: 12px;
  --shadow: 0 4px 24px rgba(0,0,0,0.4);
  --font-head: 'Syne', sans-serif;
  --font-body: 'DM Sans', sans-serif;
}

html { scroll-behavior: smooth; }
body { font-family: var(--font-body); background: var(--bg); color: var(--text); line-height: 1.6; min-height: 100vh; display: flex; flex-direction: column; }
a { color: var(--accent-light); text-decoration: none; }
a:hover { color: #fff; }
img { max-width: 100%; border-radius: 8px; }

/* ========= NAVBAR ========= */
.navbar {
  position: sticky; top: 0; z-index: 100;
  display: flex; align-items: center; gap: 1rem;
  padding: 0.9rem 2rem;
  background: rgba(13,13,20,0.9);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.navbar-brand { display: flex; align-items: center; gap: 0.5rem; font-family: var(--font-head); font-size: 1.3rem; font-weight: 800; color: #fff; margin-right: auto; }
.brand-icon { font-size: 1.5rem; }
.navbar-links { display: flex; align-items: center; gap: 0.5rem; }
.navbar-links a { color: var(--text-muted); font-size: 0.9rem; padding: 0.4rem 0.75rem; border-radius: 6px; transition: color 0.2s, background 0.2s; }
.navbar-links a:hover { color: #fff; background: var(--bg-card2); }
.navbar-links .btn-primary { background: var(--accent); color: #fff; font-weight: 600; }
.navbar-links .btn-primary:hover { background: var(--accent-light); }
.navbar-links .btn-outline { border: 1px solid var(--border); color: var(--text); }
.navbar-links .btn-outline:hover { border-color: var(--accent); color: var(--accent-light); }
.navbar-links .btn-admin { background: #2a1a4a; color: var(--accent-light); border: 1px solid #3a2a6a; }
.navbar-burger { display: none; background: none; border: none; color: var(--text); font-size: 1.3rem; cursor: pointer; }

/* ========= LAYOUT ========= */
.main-content { flex: 1; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 1.5rem; }
.section { padding: 3rem 0; }

/* ========= HERO ========= */
.hero {
  padding: 5rem 2rem;
  text-align: center;
  background: radial-gradient(ellipse 80% 50% at 50% 0%, var(--accent-glow), transparent);
  border-bottom: 1px solid var(--border);
}
.hero h1 { font-family: var(--font-head); font-size: clamp(2.2rem, 5vw, 4rem); font-weight: 800; color: #fff; line-height: 1.1; margin-bottom: 1rem; }
.hero h1 span { color: var(--accent-light); }
.hero p { color: var(--text-muted); font-size: 1.1rem; max-width: 560px; margin: 0 auto 2.5rem; }
.hero-buttons { display: flex; gap: 1rem; justify-content: center; flex-wrap: wrap; }

/* ========= BUTTONS ========= */
.btn { display: inline-flex; align-items: center; gap: 0.4rem; padding: 0.7rem 1.5rem; border-radius: var(--radius); font-family: var(--font-body); font-size: 0.95rem; font-weight: 600; cursor: pointer; transition: all 0.2s; border: none; }
.btn-lg { padding: 0.9rem 2rem; font-size: 1rem; }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-light); color: #fff; transform: translateY(-1px); box-shadow: 0 4px 16px var(--accent-glow); }
.btn-secondary { background: var(--bg-card2); color: var(--text); border: 1px solid var(--border); }
.btn-secondary:hover { border-color: var(--accent); color: #fff; }
.btn-danger { background: #3a0000; color: #f88; border: 1px solid #600; }
.btn-danger:hover { background: #600; }
.btn-success { background: #0a2a1a; color: var(--green); border: 1px solid #1a4a2a; }

/* ========= CARDS ========= */
.card { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; transition: transform 0.2s, box-shadow 0.2s; }
.card:hover { transform: translateY(-3px); box-shadow: var(--shadow); }
.card-cover { width: 100%; height: 180px; object-fit: cover; background: linear-gradient(135deg, #1a1a3a, #2a1a4a); display: flex; align-items: center; justify-content: center; font-size: 3rem; }
.card-body { padding: 1.2rem; }
.card-title { font-family: var(--font-head); font-size: 1.05rem; font-weight: 700; color: #fff; margin-bottom: 0.5rem; }
.card-desc { font-size: 0.85rem; color: var(--text-muted); line-height: 1.5; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.card-meta { display: flex; gap: 0.5rem; align-items: center; margin-top: 0.8rem; flex-wrap: wrap; }
.badge { display: inline-block; padding: 0.2rem 0.6rem; border-radius: 20px; font-size: 0.75rem; font-weight: 600; }
.badge-accent { background: var(--accent-glow); color: var(--accent-light); border: 1px solid var(--accent); }
.badge-green { background: rgba(62,207,142,0.1); color: var(--green); border: 1px solid rgba(62,207,142,0.3); }
.badge-yellow { background: rgba(245,166,35,0.1); color: var(--yellow); border: 1px solid rgba(245,166,35,0.3); }

/* ========= GRID ========= */
.courses-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 1.5rem; }

/* ========= CATEGORY FILTERS ========= */
.filters { display: flex; gap: 0.5rem; flex-wrap: wrap; margin-bottom: 2rem; }
.filter-btn { padding: 0.4rem 1rem; border-radius: 20px; border: 1px solid var(--border); background: transparent; color: var(--text-muted); font-family: var(--font-body); font-size: 0.85rem; cursor: pointer; transition: all 0.2s; }
.filter-btn:hover, .filter-btn.active { background: var(--accent); border-color: var(--accent); color: #fff; }

/* ========= COURSE PAGE ========= */
.course-header { padding: 3rem 0; border-bottom: 1px solid var(--border); background: linear-gradient(to bottom, var(--accent-glow), transparent); }
.course-header h1 { font-family: var(--font-head); font-size: clamp(1.8rem, 4vw, 3rem); font-weight: 800; color: #fff; margin-bottom: 1rem; }
.lesson-list { list-style: none; }
.lesson-item { display: flex; align-items: center; gap: 1rem; padding: 1rem 1.2rem; border-bottom: 1px solid var(--border); transition: background 0.2s; cursor: pointer; }
.lesson-item:hover { background: var(--bg-card2); }
.lesson-item.completed .lesson-num { background: var(--green); color: #000; }
.lesson-num { width: 32px; height: 32px; border-radius: 50%; background: var(--bg-card2); border: 1px solid var(--border); display: flex; align-items: center; justify-content: center; font-size: 0.8rem; color: var(--text-muted); flex-shrink: 0; }
.lesson-title { font-size: 0.95rem; color: var(--text); flex: 1; }
.lesson-tag { font-size: 0.75rem; color: var(--text-muted); }

/* ========= PROGRESS BAR ========= */
.progress-wrap { background: var(--bg-card2); border-radius: 99px; height: 6px; overflow: hidden; }
.progress-bar { height: 100%; background: linear-gradient(90deg, var(--accent), var(--green)); border-radius: 99px; transition: width 0.5s ease; }

/* ========= LESSON CONTENT ========= */
.lesson-content { max-width: 800px; }
.lesson-content h1, .lesson-content h2, .lesson-content h3 { font-family: var(--font-head); color: #fff; margin: 1.5rem 0 0.5rem; }
.lesson-content p { color: var(--text); margin-bottom: 1rem; }
.lesson-content pre { background: #0a0a14; border: 1px solid var(--border); border-radius: 8px; padding: 1rem; overflow-x: auto; font-size: 0.85rem; margin: 1rem 0; }
.lesson-content code { font-family: monospace; color: var(--accent-light); }
.lesson-content ul, .lesson-content ol { padding-left: 1.5rem; margin-bottom: 1rem; }
.lesson-content li { color: var(--text); margin-bottom: 0.3rem; }
.lesson-content blockquote { border-left: 3px solid var(--accent); padding-left: 1rem; color: var(--text-muted); font-style: italic; margin: 1rem 0; }

/* ========= FORMS ========= */
.form-group { margin-bottom: 1.2rem; }
.form-label { display: block; font-size: 0.85rem; color: var(--text-muted); margin-bottom: 0.4rem; }
.form-control { width: 100%; padding: 0.75rem 1rem; background: var(--bg); border: 1px solid var(--border); border-radius: 8px; color: var(--text); font-family: var(--font-body); font-size: 0.95rem; transition: border-color 0.2s; }
.form-control:focus { outline: none; border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-glow); }
textarea.form-control { resize: vertical; min-height: 120px; }
select.form-control { cursor: pointer; }
.form-hint { font-size: 0.78rem; color: var(--text-muted); margin-top: 0.3rem; }

/* ========= AUTH PAGES ========= */
.auth-wrapper { display: flex; align-items: center; justify-content: center; min-height: calc(100vh - 120px); padding: 2rem; }
.auth-card { background: var(--bg-card); border: 1px solid var(--border); border-radius: 16px; padding: 2.5rem; width: 100%; max-width: 420px; }
.auth-title { font-family: var(--font-head); font-size: 1.8rem; font-weight: 800; color: #fff; margin-bottom: 0.3rem; }
.auth-sub { color: var(--text-muted); font-size: 0.9rem; margin-bottom: 2rem; }

/* ========= ALERTS ========= */
.alert { padding: 0.9rem 1.2rem; border-radius: 8px; font-size: 0.9rem; margin-bottom: 1.2rem; }
.alert-error { background: rgba(255,0,68,0.1); border: 1px solid rgba(255,0,68,0.3); color: #ff8899; }
.alert-success { background: rgba(62,207,142,0.1); border: 1px solid rgba(62,207,142,0.3); color: var(--green); }
.alert-info { background: var(--accent-glow); border: 1px solid var(--accent); color: var(--accent-light); }

/* ========= STATS ========= */
.stats-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 1rem; margin-bottom: 2rem; }
.stat-card { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.2rem; text-align: center; }
.stat-number { font-family: var(--font-head); font-size: 2rem; font-weight: 800; color: var(--accent-light); }
.stat-label { font-size: 0.8rem; color: var(--text-muted); margin-top: 0.2rem; }

/* ========= TABLE ========= */
.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: 0.9rem; }
th { text-align: left; padding: 0.75rem 1rem; background: var(--bg-card2); color: var(--text-muted); font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.05em; border-bottom: 1px solid var(--border); }
td { padding: 0.75rem 1rem; border-bottom: 1px solid var(--border); color: var(--text); }
tr:hover td { background: var(--bg-card2); }

/* ========= VIDEO EMBED ========= */
.video-wrap { position: relative; padding-top: 56.25%; border-radius: var(--radius); overflow: hidden; background: #000; margin-bottom: 1.5rem; }
.video-wrap iframe { position: absolute; top: 0; left: 0; width: 100%; height: 100%; border: none; }

/* ========= SIDEBAR LAYOUT ========= */
.sidebar-layout { display: grid; grid-template-columns: 1fr 340px; gap: 2rem; align-items: start; }
.sidebar { position: sticky; top: 80px; background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; }
.sidebar-header { padding: 1rem 1.2rem; border-bottom: 1px solid var(--border); font-family: var(--font-head); font-weight: 700; font-size: 0.9rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.05em; }

/* ========= PAGE HEADERS ========= */
.page-header { padding: 2.5rem 0 2rem; border-bottom: 1px solid var(--border); margin-bottom: 2rem; }
.page-header h1 { font-family: var(--font-head); font-size: 2rem; font-weight: 800; color: #fff; }
.page-header p { color: var(--text-muted); margin-top: 0.3rem; }

/* ========= FOOTER ========= */
.footer { border-top: 1px solid var(--border); padding: 1.5rem 2rem; text-align: center; font-size: 0.8rem; color: var(--text-muted); }

/* ========= RESPONSIVE ========= */
@media (max-width: 900px) {
  .sidebar-layout { grid-template-columns: 1fr; }
  .sidebar { position: static; }
}
@media (max-width: 600px) {
  .navbar-links { display: none; flex-direction: column; position: absolute; top: 100%; left: 0; right: 0; background: var(--bg); border-bottom: 1px solid var(--border); padding: 1rem; }
  .navbar.open .navbar-links { display: flex; }
  .navbar-burger { display: block; }
  .navbar { position: relative; }
  .hero { padding: 3rem 1.5rem; }
  .courses-grid { grid-template-columns: 1fr; }
}