:root {
  --bg: #0d0d14;
  --bg-sidebar: #13131c;
  --card-bg: rgba(255, 255, 255, 0.04);
  --card-border: rgba(255, 255, 255, 0.08);
  --text-main: #ffffff;
  --text-sub: rgba(255, 255, 255, 0.6);
  --accent: #2563eb;
  --accent-glow: rgba(37, 99, 235, 0.25);
  --red: #e11d48;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: 'IBM Plex Sans', sans-serif;
  background: var(--bg);
  color: var(--text-main);
  min-height: 100vh;
  overflow-x: hidden;
}

/* Layout */
.app-layout {
  display: flex;
  height: 100vh;
}

/* Sidebar */
.sidebar {
  width: 260px;
  background: var(--bg-sidebar);
  border-right: 1px solid rgba(255, 255, 255, 0.06);
  display: flex;
  flex-direction: column;
  padding: 24px 20px;
}

.brand {
  font-family: 'Syne', sans-serif;
  font-size: 1.25rem;
  font-weight: 800;
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 48px;
  padding-left: 12px;
}

.nav-section {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.nav-label {
  font-size: 0.7rem;
  color: rgba(255, 255, 255, 0.4);
  font-weight: 600;
  letter-spacing: 0.05em;
  padding-left: 12px;
  margin-bottom: 8px;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px;
  border-radius: 10px;
  color: var(--text-sub);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  transition: all 0.2s;
}

.nav-item:hover {
  background: rgba(255, 255, 255, 0.03);
  color: var(--text-main);
}

.nav-item.active {
  background: rgba(37, 99, 235, 0.15);
  color: #60a5fa;
  border: 1px solid rgba(37, 99, 235, 0.3);
}

.nav-icon {
  font-size: 1.1rem;
}

/* Main Area */
.main-area {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow-y: auto;
}

/* Header */
.top-hdr {
  height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 40px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  background: rgba(13, 13, 20, 0.8);
  backdrop-filter: blur(12px);
  position: sticky;
  top: 0;
  z-index: 10;
}

.greeting {
  font-family: 'Syne', sans-serif;
  font-size: 1.25rem;
  font-weight: 700;
}

.greeting span {
  color: #60a5fa;
}

.hdr-actions {
  display: flex;
  gap: 12px;
}

.hdr-link {
  color: var(--text-sub);
  text-decoration: none;
  font-size: 0.85rem;
  padding: 8px 16px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 8px;
  transition: all 0.2s;
  background: rgba(255, 255, 255, 0.02);
}

.hdr-link:hover {
  background: rgba(255, 255, 255, 0.08);
  color: #fff;
}

/* Content Wrap */
.content-wrap {
  padding: 40px;
  max-width: 1200px;
}

.section-header {
  margin-bottom: 40px;
}

.section-header h1 {
  font-family: 'Syne', sans-serif;
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 8px;
}

.section-header p {
  color: var(--text-sub);
  font-size: 1rem;
}

/* Cards */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 24px;
}

.exam-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 16px;
  padding: 24px;
  position: relative;
  transition: all 0.25s ease;
  display: flex;
  flex-direction: column;
}

.exam-card:hover {
  border-color: rgba(96, 165, 250, 0.4);
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.4);
}

.card-icon {
  font-size: 2.2rem;
  margin-bottom: 16px;
}

.card-tag {
  position: absolute;
  top: 24px;
  right: 24px;
  font-size: 0.72rem;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 20px;
  text-transform: uppercase;
}

.card-tag.free {
  background: rgba(16, 185, 129, 0.15);
  color: #34d399;
  border: 1px solid rgba(16, 185, 129, 0.3);
}

.card-tag.locked {
  background: rgba(239, 68, 68, 0.15);
  color: #f87171;
  border: 1px solid rgba(239, 68, 68, 0.3);
}

.card-num {
  font-size: 0.8rem;
  color: #60a5fa;
  font-family: 'IBM Plex Mono', monospace;
  margin-bottom: 6px;
  text-transform: uppercase;
}

.card-title {
  font-family: 'Syne', sans-serif;
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 10px;
}

.card-sub {
  color: var(--text-sub);
  font-size: 0.9rem;
  margin-bottom: 24px;
  line-height: 1.6;
  flex: 1;
}

.card-btn {
  display: inline-block;
  width: 100%;
  text-align: center;
  background: linear-gradient(135deg, #2563eb, #1d4ed8);
  color: #fff;
  text-decoration: none;
  padding: 12px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 0.95rem;
  transition: all 0.2s;
}

.card-btn:hover {
  background: #1d4ed8;
  box-shadow: 0 4px 20px var(--accent-glow);
}

/* Tabs */
.tabs {
  display: flex;
  gap: 12px;
  margin-bottom: 32px;
}

.tab-btn {
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.1);
  color: var(--text-sub);
  padding: 10px 20px;
  border-radius: 10px;
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
}

.tab-btn:hover {
  background: rgba(255, 255, 255, 0.08);
  color: #fff;
}

.tab-btn.active {
  background: linear-gradient(135deg, #2563eb, #1d4ed8);
  color: #fff;
  border-color: #3b82f6;
  box-shadow: 0 4px 20px var(--accent-glow);
}

.tab-content {
  display: none;
}

.tab-content.active {
  display: block;
}

/* Modal */
.modal-bg { position: fixed; inset: 0; background: rgba(13,13,20,0.8); z-index: 200; display: none; align-items: center; justify-content: center; backdrop-filter: blur(6px) }
.modal-bg.open { display: flex }
.modal-box { background: #1e293b; border: 1px solid rgba(255,255,255,0.15); border-radius: 16px; padding: 28px; width: 92%; max-width: 400px; color: #fff; position: relative; }
.modal-hdr { display: flex; justify-content: space-between; align-items: center; margin-bottom: 24px; border-bottom: 1px solid rgba(255,255,255,0.1); padding-bottom: 12px }
.btn-action { background: transparent; border: none; color: rgba(255,255,255,0.6); font-size: 0.9rem; cursor: pointer; transition: color 0.2s }
.btn-action:hover { color: #fff }