/* ==============================================================================
   VANLHH LMS & CURRICULUM PLATFORM - MODERN GLASSMORPHISM DESIGN SYSTEM
   ============================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Outfit:wght@500;600;700;800&display=swap');

:root {
  /* Color Tokens */
  --bg-primary: #0b0f19;
  --bg-secondary: #111827;
  --bg-card: rgba(17, 24, 39, 0.75);
  --bg-card-hover: rgba(31, 41, 55, 0.85);
  --bg-glass: rgba(255, 255, 255, 0.04);
  --border-color: rgba(255, 255, 255, 0.08);
  --border-highlight: rgba(99, 102, 241, 0.4);

  --text-primary: #f9fafb;
  --text-secondary: #9ca3af;
  --text-muted: #6b7280;

  /* Accent Colors */
  --primary: #6366f1;
  --primary-hover: #4f46e5;
  --primary-glow: rgba(99, 102, 241, 0.35);
  
  --emerald: #10b981;
  --emerald-glow: rgba(16, 185, 129, 0.25);
  --amber: #f59e0b;
  --rose: #f43f5e;
  --sky: #0ea5e9;

  /* Typography */
  --font-body: 'Inter', -apple-system, sans-serif;
  --font-display: 'Outfit', sans-serif;

  /* Dimensions */
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  --shadow-card: 0 10px 30px -10px rgba(0, 0, 0, 0.5);
}

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

body {
  font-family: var(--font-body);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.5;
  background-image: 
    radial-gradient(at 0% 0%, rgba(99, 102, 241, 0.15) 0px, transparent 50%),
    radial-gradient(at 100% 100%, rgba(16, 185, 129, 0.1) 0px, transparent 50%),
    radial-gradient(at 50% 50%, rgba(14, 165, 233, 0.05) 0px, transparent 50%);
  background-attachment: fixed;
}

/* Utility Containers */
.container {
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 24px;
}

/* App Header */
.app-header {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  background: rgba(11, 15, 25, 0.8);
  border-bottom: 1px solid var(--border-color);
  padding: 16px 0;
}

.header-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand-badge {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--text-primary);
}

.brand-icon {
  width: 44px;
  height: 44px;
  background: linear-gradient(135deg, var(--primary), var(--sky));
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  box-shadow: 0 0 20px var(--primary-glow);
}

.brand-name {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 800;
  letter-spacing: -0.5px;
  background: linear-gradient(135deg, #fff, #cbd5e1);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.brand-sub {
  font-size: 12px;
  color: var(--text-secondary);
}

/* Cloud Status Pill */
.cloud-pill {
  display: flex;
  align-items: center;
  gap: 8px;
  background: rgba(16, 185, 129, 0.12);
  border: 1px solid rgba(16, 185, 129, 0.3);
  padding: 6px 12px;
  border-radius: var(--radius-full);
  font-size: 12px;
  color: #34d399;
  font-weight: 600;
}

.pulse-dot {
  width: 8px;
  height: 8px;
  background: #34d399;
  border-radius: 50%;
  box-shadow: 0 0 10px #34d399;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0% { transform: scale(0.95); opacity: 0.8; }
  50% { transform: scale(1.2); opacity: 1; }
  100% { transform: scale(0.95); opacity: 0.8; }
}

/* Role Toggle & Header Controls */
.header-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

.role-switcher {
  display: flex;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  padding: 4px;
  gap: 4px;
}

.role-btn {
  padding: 6px 14px;
  border-radius: var(--radius-full);
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  display: flex;
  align-items: center;
  gap: 6px;
}

.role-btn.active {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 2px 10px var(--primary-glow);
}

/* Hero Section */
.hero-banner {
  padding: 40px 0 24px;
  text-align: center;
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  background: rgba(99, 102, 241, 0.12);
  border: 1px solid rgba(99, 102, 241, 0.3);
  border-radius: var(--radius-full);
  color: #a5b4fc;
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 18px;
}

.hero-title {
  font-family: var(--font-display);
  font-size: 38px;
  font-weight: 800;
  letter-spacing: -1px;
  line-height: 1.2;
  margin-bottom: 12px;
  background: linear-gradient(135deg, #ffffff 40%, #a5b4fc 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-desc {
  font-size: 16px;
  color: var(--text-secondary);
  max-width: 680px;
  margin: 0 auto 28px;
}

/* Metric Counter Cards */
.metric-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-bottom: 32px;
}

.metric-card {
  background: var(--bg-card);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 20px;
  display: flex;
  align-items: center;
  gap: 16px;
  box-shadow: var(--shadow-card);
}

.metric-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background: var(--bg-glass);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
}

.metric-val {
  font-family: var(--font-display);
  font-size: 24px;
  font-weight: 700;
  color: var(--text-primary);
}

.metric-lbl {
  font-size: 12px;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* Nav Tabs */
.tab-navigation {
  display: flex;
  gap: 8px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  padding: 6px;
  border-radius: var(--radius-lg);
  margin-bottom: 28px;
  overflow-x: auto;
}

.nav-tab-btn {
  flex: 1;
  padding: 12px 20px;
  border-radius: var(--radius-md);
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.25s ease;
  white-space: nowrap;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
}

.nav-tab-btn:hover {
  color: var(--text-primary);
  background: var(--bg-glass);
}

.nav-tab-btn.active {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 4px 15px var(--primary-glow);
}

/* Tab Content Areas */
.tab-pane {
  display: none;
}
.tab-pane.active {
  display: block;
}

/* ==============================================================================
   PHÂN HỆ 1: LỘ TRÌNH 36 BUỔI (CURRICULUM)
   ============================================================================== */
.phase-filters {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
  gap: 16px;
  flex-wrap: wrap;
}

.filter-pills {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.filter-btn {
  padding: 8px 16px;
  border-radius: var(--radius-full);
  border: 1px solid var(--border-color);
  background: var(--bg-secondary);
  color: var(--text-secondary);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
}

.filter-btn.active {
  background: rgba(99, 102, 241, 0.15);
  border-color: var(--primary);
  color: #a5b4fc;
}

.timeline-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 18px;
}

.session-card {
  background: var(--bg-card);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 20px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 16px;
  transition: transform 0.2s, border-color 0.2s;
  position: relative;
  overflow: hidden;
}

.session-card:hover {
  transform: translateY(-3px);
  border-color: var(--border-highlight);
}

.session-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  height: 100%;
  background: var(--border-color);
}

.session-card.completed::before { background: var(--emerald); }
.session-card.in-progress::before { background: var(--amber); }
.session-card.upcoming::before { background: var(--primary); }

.session-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 10px;
}

.session-num {
  font-family: var(--font-display);
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-muted);
}

.status-badge {
  font-size: 11px;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: var(--radius-full);
  text-transform: uppercase;
}

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

.status-badge.in-progress {
  background: rgba(245, 158, 11, 0.15);
  color: #fbbf24;
  border: 1px solid rgba(245, 158, 11, 0.3);
}

.status-badge.upcoming {
  background: rgba(99, 102, 241, 0.15);
  color: #a5b4fc;
  border: 1px solid rgba(99, 102, 241, 0.3);
}

.session-title {
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 700;
  color: var(--text-primary);
  margin-top: 4px;
}

.session-desc {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.4;
  margin-top: 6px;
}

.session-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 14px;
  border-top: 1px solid var(--border-color);
}

.session-meta {
  font-size: 12px;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 6px;
}

.btn-sm {
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  font-size: 12px;
  font-weight: 600;
  border: 1px solid var(--border-color);
  background: var(--bg-glass);
  color: var(--text-primary);
  cursor: pointer;
  transition: all 0.2s;
}

.btn-sm:hover {
  background: var(--primary);
  border-color: var(--primary);
}

/* ==============================================================================
   PHÂN HỆ 2: HỆ THỐNG ĐIỂM DANH (ATTENDANCE)
   ============================================================================== */
.attendance-header-box {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px;
  margin-bottom: 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
}

.session-selector {
  display: flex;
  align-items: center;
  gap: 12px;
}

.custom-select {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 10px 16px;
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 600;
  outline: none;
}

.custom-select:focus {
  border-color: var(--primary);
}

.table-wrapper {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-card);
}

.custom-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
}

.custom-table th {
  background: var(--bg-secondary);
  padding: 14px 18px;
  font-size: 12px;
  font-weight: 700;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  border-bottom: 1px solid var(--border-color);
}

.custom-table td {
  padding: 16px 18px;
  border-bottom: 1px solid var(--border-color);
  font-size: 14px;
}

.custom-table tr:last-child td {
  border-bottom: none;
}

.custom-table tr:hover {
  background: var(--bg-glass);
}

.student-info {
  display: flex;
  align-items: center;
  gap: 12px;
}

.student-avatar {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  background: linear-gradient(135deg, var(--primary), var(--sky));
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 14px;
}

.attendance-btns {
  display: flex;
  gap: 6px;
}

.att-btn {
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  font-size: 12px;
  font-weight: 600;
  border: 1px solid var(--border-color);
  background: var(--bg-secondary);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.2s;
}

.att-btn.present.active {
  background: var(--emerald);
  color: #fff;
  border-color: var(--emerald);
}

.att-btn.absent.active {
  background: var(--rose);
  color: #fff;
  border-color: var(--rose);
}

.att-btn.late.active {
  background: var(--amber);
  color: #fff;
  border-color: var(--amber);
}

.progress-bar-wrap {
  width: 120px;
  height: 8px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-full);
  overflow: hidden;
  margin-top: 4px;
}

.progress-fill {
  height: 100%;
  border-radius: var(--radius-full);
  background: var(--emerald);
}

/* ==============================================================================
   PHÂN HỆ 3: LMS QUIZ ENGINE
   ============================================================================== */
.quiz-container {
  max-width: 800px;
  margin: 0 auto;
}

.quiz-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-card);
}

.quiz-meta-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 24px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-color);
}

.timer-box {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 700;
  color: var(--amber);
  background: rgba(245, 158, 11, 0.12);
  padding: 6px 14px;
  border-radius: var(--radius-full);
  border: 1px solid rgba(245, 158, 11, 0.3);
}

.quiz-question-text {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 20px;
  color: #fff;
  line-height: 1.5;
}

.quiz-options-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 28px;
}

.quiz-opt-btn {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 16px 20px;
  text-align: left;
  font-size: 15px;
  color: var(--text-primary);
  cursor: pointer;
  transition: all 0.2s ease;
  display: flex;
  align-items: center;
  gap: 14px;
}

.quiz-opt-btn:hover {
  background: var(--bg-card-hover);
  border-color: var(--primary);
}

.quiz-opt-btn.selected {
  background: rgba(99, 102, 241, 0.2);
  border-color: var(--primary);
  color: #fff;
  font-weight: 600;
}

.quiz-opt-btn.correct {
  background: rgba(16, 185, 129, 0.2);
  border-color: var(--emerald);
  color: #34d399;
}

.quiz-opt-btn.wrong {
  background: rgba(244, 63, 94, 0.2);
  border-color: var(--rose);
  color: #fb7185;
}

.quiz-opt-letter {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-full);
  background: var(--bg-glass);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 13px;
  flex-shrink: 0;
}

.quiz-explanation-box {
  background: rgba(16, 185, 129, 0.1);
  border: 1px solid rgba(16, 185, 129, 0.3);
  padding: 16px;
  border-radius: var(--radius-md);
  margin-top: 20px;
  font-size: 14px;
  color: #a7f3d0;
  line-height: 1.5;
}

.btn-primary {
  background: var(--primary);
  color: #fff;
  border: none;
  padding: 12px 28px;
  border-radius: var(--radius-md);
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.2s;
  box-shadow: 0 4px 15px var(--primary-glow);
}

.btn-primary:hover {
  background: var(--primary-hover);
  transform: translateY(-2px);
}

/* ==============================================================================
   PHÂN HỆ 4: HỌC BẠ & ĐÁNH GIÁ NĂNG LỰC
   ============================================================================== */
.report-search-bar {
  display: flex;
  gap: 12px;
  max-width: 500px;
  margin: 0 auto 32px;
}

.report-search-input {
  flex: 1;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  color: #fff;
  padding: 12px 18px;
  border-radius: var(--radius-md);
  font-size: 15px;
  outline: none;
}

.report-search-input:focus {
  border-color: var(--primary);
}

.report-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 32px;
  margin-bottom: 24px;
}

.skills-radar-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 16px;
  margin: 24px 0;
}

.skill-bar-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  padding: 16px;
  border-radius: var(--radius-md);
  text-align: center;
}

.skill-name {
  font-size: 12px;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

.skill-percent {
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 800;
  color: var(--primary);
}

.guarantee-box {
  padding: 20px;
  border-radius: var(--radius-md);
  background: rgba(16, 185, 129, 0.12);
  border: 1px solid rgba(16, 185, 129, 0.3);
  display: flex;
  align-items: center;
  gap: 16px;
  margin-top: 24px;
}

/* ==============================================================================
   PHÂN HỆ 5: TEACHER STUDIO (CMS & QUESTION BUILDER)
   ============================================================================== */
.studio-header {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px;
  margin-bottom: 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
}

.studio-subnav {
  display: flex;
  gap: 8px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  padding: 6px;
  border-radius: var(--radius-md);
  margin-bottom: 24px;
  overflow-x: auto;
}

.studio-tab-btn {
  padding: 10px 18px;
  border-radius: var(--radius-sm);
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-weight: 600;
  font-size: 14px;
  cursor: pointer;
  transition: all 0.2s;
  white-space: nowrap;
}

.studio-tab-btn.active {
  background: rgba(99, 102, 241, 0.2);
  color: #a5b4fc;
  border: 1px solid var(--primary);
}

.studio-subpane {
  display: none;
}
.studio-subpane.active {
  display: block;
}

.studio-form-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 28px;
  box-shadow: var(--shadow-card);
}

.form-group {
  margin-bottom: 18px;
}

.form-label {
  display: block;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

.form-input, .form-textarea {
  width: 100%;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  color: #fff;
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  font-family: var(--font-body);
  font-size: 14px;
  outline: none;
  transition: border-color 0.2s;
}

.form-input:focus, .form-textarea:focus {
  border-color: var(--primary);
}

.question-builder-item {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 18px;
  margin-bottom: 16px;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
}

.question-builder-item:hover {
  border-color: var(--border-highlight);
}

/* Modal Windows */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(8px);
  z-index: 1000;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.modal-backdrop.open {
  display: flex;
}

.modal-content {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  max-width: 640px;
  width: 100%;
  max-height: 85vh;
  overflow-y: auto;
  padding: 28px;
  box-shadow: var(--shadow-card);
  position: relative;
}

.modal-close-btn {
  position: absolute;
  top: 20px;
  right: 20px;
  background: var(--bg-glass);
  border: none;
  color: var(--text-secondary);
  width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
  cursor: pointer;
  font-size: 16px;
}

/* Toast Notifications */
.toast-msg {
  position: fixed;
  bottom: 24px;
  right: 24px;
  background: var(--bg-secondary);
  border: 1px solid var(--primary);
  color: #fff;
  padding: 12px 20px;
  border-radius: var(--radius-md);
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.5);
  display: flex;
  align-items: center;
  gap: 10px;
  z-index: 9999;
  transform: translateY(100px);
  opacity: 0;
  transition: all 0.3s ease;
}

.toast-msg.show {
  transform: translateY(0);
  opacity: 1;
}

/* Print Stylesheet for A4 Worksheets */
@media print {
  body {
    background: #fff !important;
    color: #000 !important;
  }
  .app-header, .hero-banner, .tab-navigation, .header-actions, .phase-filters, .btn-sm, .btn-primary, .modal-close-btn {
    display: none !important;
  }
  .modal-backdrop {
    position: static !important;
    background: transparent !important;
    display: block !important;
    padding: 0 !important;
  }
  .modal-content {
    background: #fff !important;
    border: none !important;
    color: #000 !important;
    box-shadow: none !important;
    max-width: 100% !important;
    padding: 0 !important;
  }
  .modal-content pre, .modal-content div {
    color: #000 !important;
    background: #f8fafc !important;
    border: 1px solid #cbd5e1 !important;
  }
}

/* Responsive adjustments */
@media (max-width: 900px) {
  .metric-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .skills-radar-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 640px) {
  .hero-title {
    font-size: 28px;
  }
  .metric-grid {
    grid-template-columns: 1fr;
  }
  .timeline-grid {
    grid-template-columns: 1fr;
  }
  .tab-navigation {
    flex-direction: column;
  }
}