/* ========================================================
   SHTECH AI ACADEMY - DESIGN SYSTEM & STYLESHEET
   Màu sắc thương hiệu:
   - Xanh công nghệ SHTECH: #2a4094
   - Cam công trường SHTECH: #f7941d
   - Xanh lá thành công: #10b981
   ======================================================== */

:root {
  --primary-blue: #2a4094;
  --primary-blue-dark: #1e2e6b;
  --primary-blue-light: #e8ecf8;
  --primary-orange: #f7941d;
  --primary-orange-dark: #d67b0d;
  --primary-orange-light: #fff5ea;
  
  --success-green: #10b981;
  --success-green-light: #ecfdf5;
  --danger-red: #ef4444;
  --danger-red-light: #fef2f2;
  --purple-accent: #8b5cf6;

  --bg-page: #f8fafc;
  --bg-card: #ffffff;
  --bg-sidebar: #ffffff;
  --border-color: #e2e8f0;
  --border-hover: #cbd5e1;

  --text-main: #0f172a;
  --text-muted: #64748b;
  --text-light: #94a3b8;

  --font-heading: 'Plus Jakarta Sans', system-ui, -apple-system, sans-serif;
  --font-body: 'Inter', system-ui, -apple-system, sans-serif;

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -2px rgba(0, 0, 0, 0.04);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.04);

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-full: 9999px;

  --header-height: 70px;
}

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

body {
  font-family: var(--font-body);
  background-color: var(--bg-page);
  color: var(--text-main);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ========================================================
   1. TOP NAVIGATION BAR
   ======================================================== */
.top-nav {
  height: var(--header-height);
  background-color: #ffffff;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}

.nav-left {
  display: flex;
  align-items: center;
  gap: 16px;
}

.brand-block {
  display: flex;
  align-items: center;
  gap: 12px;
  cursor: pointer;
  text-decoration: none;
}

.brand-logo {
  height: 44px;
  width: auto;
  object-fit: contain;
  border-radius: var(--radius-sm);
}

.brand-logo-fallback {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 22px;
  letter-spacing: -0.5px;
}
.fallback-blue { color: var(--primary-blue); }
.fallback-orange { color: var(--primary-orange); }

.brand-text {
  display: flex;
  flex-direction: column;
}

.brand-title {
  font-family: var(--font-heading);
  font-size: 17px;
  font-weight: 800;
  color: var(--primary-blue);
  line-height: 1.2;
  letter-spacing: -0.3px;
}

.brand-sub {
  font-size: 11px;
  color: var(--text-muted);
  font-weight: 500;
}

.highlight-orange {
  color: var(--primary-orange);
}

/* CENTER TABS */
.nav-center {
  display: flex;
  align-items: center;
}

.track-tab-group {
  display: flex;
  background-color: #f1f5f9;
  padding: 4px;
  border-radius: var(--radius-full);
  gap: 4px;
}

.track-tab {
  border: none;
  background: transparent;
  padding: 8px 16px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: all 0.2s ease;
  display: flex;
  align-items: center;
  gap: 6px;
}

.track-tab:hover {
  color: var(--primary-blue);
}

.track-tab.active {
  background-color: #ffffff;
  color: var(--primary-blue);
  box-shadow: var(--shadow-sm);
}

/* NAV RIGHT */
.nav-right {
  display: flex;
  align-items: center;
  gap: 14px;
}

.btn-outline-admin {
  background-color: var(--primary-orange-light);
  border: 1px solid var(--primary-orange);
  color: var(--primary-orange-dark);
  font-weight: 700;
  font-size: 13px;
  padding: 7px 14px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  transition: all 0.2s;
}

.btn-outline-admin:hover {
  background-color: var(--primary-orange);
  color: #ffffff;
}

.admin-badge {
  background-color: var(--primary-orange);
  color: #ffffff;
  font-size: 10px;
  padding: 2px 6px;
  border-radius: 4px;
  text-transform: uppercase;
  font-weight: 800;
}

.btn-outline-admin:hover .admin-badge {
  background-color: #ffffff;
  color: var(--primary-orange);
}

/* PROGRESS WIDGET PILL */
.progress-pill {
  display: flex;
  align-items: center;
  gap: 10px;
  background-color: #f8fafc;
  border: 1px solid var(--border-color);
  padding: 6px 14px;
  border-radius: var(--radius-full);
}

.progress-circle {
  width: 30px;
  height: 30px;
}

.circular-chart {
  display: block;
  max-width: 100%;
  max-height: 100%;
}

.circle-bg {
  fill: none;
  stroke: #e2e8f0;
  stroke-width: 3.8;
}

.circle {
  fill: none;
  stroke-width: 3.8;
  stroke-linecap: round;
  stroke: var(--primary-orange);
  transition: stroke-dasharray 0.5s ease;
}

.progress-pill-info {
  display: flex;
  flex-direction: column;
}

.progress-num {
  font-size: 11px;
  color: var(--text-muted);
  font-weight: 500;
}

.progress-pct {
  font-size: 13px;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1.1;
}

/* USER META PILL */
.logged-user-pill {
  display: flex;
  align-items: center;
  gap: 10px;
  background-color: var(--primary-blue-light);
  border: 1px solid rgba(42, 64, 148, 0.2);
  padding: 5px 12px;
  border-radius: var(--radius-full);
}

.user-avatar {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  object-fit: cover;
  border: 2px solid #ffffff;
}

.user-meta {
  display: flex;
  flex-direction: column;
}

.user-name {
  font-size: 12px;
  font-weight: 700;
  color: var(--primary-blue);
  line-height: 1.2;
}

.user-email {
  font-size: 10px;
  color: var(--text-muted);
}

.icon-btn-logout {
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 14px;
  cursor: pointer;
  padding: 4px;
  border-radius: 50%;
  transition: all 0.2s;
}

.icon-btn-logout:hover {
  color: var(--danger-red);
}

/* ========================================================
   2. APP LAYOUT
   ======================================================== */
.app-layout {
  display: flex;
  flex: 1;
  height: calc(100vh - var(--header-height));
  overflow: hidden;
}

/* ========================================================
   3. SIDEBAR (CURRICULUM TREE)
   ======================================================== */
.sidebar {
  width: 360px;
  background-color: var(--bg-sidebar);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  flex-shrink: 0;
  height: 100%;
}

.sidebar-header {
  padding: 16px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  gap: 12px;
  background-color: #fafbfc;
}

.search-box {
  display: flex;
  align-items: center;
  background-color: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 8px 12px;
  gap: 8px;
  transition: border-color 0.2s;
}

.search-box:focus-within {
  border-color: var(--primary-blue);
  box-shadow: 0 0 0 3px rgba(42, 64, 148, 0.1);
}

.search-box i {
  color: var(--text-light);
  font-size: 14px;
}

.search-box input {
  border: none;
  background: transparent;
  outline: none;
  width: 100%;
  font-size: 13px;
  font-family: inherit;
  color: var(--text-main);
}

.clear-search {
  background: none;
  border: none;
  color: var(--text-light);
  cursor: pointer;
  padding: 2px;
}

.track-dropdown-wrap {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.track-dropdown-wrap label {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 0.5px;
}

.custom-select select {
  width: 100%;
  padding: 9px 12px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  background-color: #ffffff;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-main);
  outline: none;
  cursor: pointer;
  font-family: inherit;
  transition: all 0.2s;
}

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

/* CURRICULUM TREE NAV */
.curriculum-nav {
  flex: 1;
  overflow-y: auto;
  padding: 12px 10px;
}

.curriculum-nav::-webkit-scrollbar {
  width: 6px;
}
.curriculum-nav::-webkit-scrollbar-thumb {
  background-color: #e2e8f0;
  border-radius: 4px;
}

.chang-group {
  margin-bottom: 14px;
}

.chang-header {
  padding: 8px 12px;
  font-family: var(--font-heading);
  font-size: 11px;
  font-weight: 800;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 0.6px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-radius: var(--radius-sm);
  background-color: #f8fafc;
  margin-bottom: 4px;
}

.chang-progress-badge {
  font-size: 10px;
  font-weight: 700;
  color: var(--primary-blue);
  background: #ffffff;
  padding: 2px 6px;
  border-radius: 10px;
  border: 1px solid var(--border-color);
}

.lesson-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 10px 12px;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.15s ease;
  margin-bottom: 2px;
  text-decoration: none;
  position: relative;
}

.lesson-item:hover {
  background-color: #f1f5f9;
}

.lesson-item.active {
  background-color: var(--primary-blue-light);
  border-left: 4px solid var(--primary-blue);
}

.lesson-status-icon {
  font-size: 16px;
  margin-top: 2px;
  color: var(--text-light);
  flex-shrink: 0;
  transition: color 0.2s;
}

.lesson-item.completed .lesson-status-icon {
  color: var(--success-green);
}

.lesson-item.active .lesson-status-icon {
  color: var(--primary-blue);
}

.lesson-info {
  display: flex;
  flex-direction: column;
  flex: 1;
  min-width: 0;
}

.lesson-num {
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 2px;
}

.lesson-name {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-main);
  line-height: 1.35;
  white-space: normal;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.lesson-item.active .lesson-name {
  color: var(--primary-blue);
  font-weight: 700;
}

/* SIDEBAR FOOTER */
.sidebar-footer {
  padding: 12px 16px;
  border-top: 1px solid var(--border-color);
  background-color: #ffffff;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.sidebar-stats {
  display: flex;
  justify-content: space-between;
  font-size: 12px;
}

.stat-label {
  color: var(--text-muted);
}

.stat-val {
  font-weight: 700;
  color: var(--text-main);
}

.stat-val.highlight {
  color: var(--success-green);
}

.sidebar-support {
  font-size: 11px;
  color: var(--text-muted);
}

.sidebar-support a {
  color: var(--primary-blue);
  text-decoration: none;
  font-weight: 600;
}

/* ========================================================
   4. CONTENT WORKSPACE & LESSON VIEWER
   ======================================================== */
.content-workspace {
  flex: 1;
  overflow-y: auto;
  padding: 32px 48px;
  background-color: #f8fafc;
}

.lesson-viewer {
  max-width: 900px;
  margin: 0 auto;
  background-color: #ffffff;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  padding: 40px;
}

/* LESSON HEADER */
.lesson-header {
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 24px;
  margin-bottom: 32px;
}

.lesson-breadcrumbs {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-muted);
  margin-bottom: 14px;
}

.crumb-link {
  color: var(--primary-blue);
  cursor: pointer;
}

.crumb-active {
  color: var(--primary-orange);
}

.lesson-title-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 20px;
  margin-bottom: 16px;
}

.lesson-title {
  font-family: var(--font-heading);
  font-size: 26px;
  font-weight: 800;
  color: var(--text-main);
  line-height: 1.3;
  letter-spacing: -0.5px;
}

.lesson-meta-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.meta-tag {
  font-size: 11px;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: var(--radius-full);
  display: inline-flex;
  align-items: center;
  gap: 5px;
  background-color: #f1f5f9;
  color: var(--text-muted);
}

.badge-track {
  background-color: var(--primary-blue-light);
  color: var(--primary-blue);
}

.badge-status.done {
  background-color: var(--success-green-light);
  color: var(--success-green);
}

.badge-hot {
  background-color: var(--primary-orange-light);
  color: var(--primary-orange-dark);
}

/* COMPLETE BUTTON */
.btn-complete {
  background-color: #f1f5f9;
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  font-weight: 700;
  font-size: 13px;
  padding: 8px 16px;
  border-radius: var(--radius-md);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 8px;
  transition: all 0.2s ease;
  white-space: nowrap;
}

.btn-complete:hover {
  background-color: #e2e8f0;
  color: var(--text-main);
}

.btn-complete.completed {
  background-color: var(--success-green);
  border-color: var(--success-green);
  color: #ffffff;
}

/* LESSON BODY CONTENT */
.content-section {
  margin-bottom: 36px;
}

.section-title {
  font-family: var(--font-heading);
  font-size: 18px;
  font-weight: 800;
  color: var(--primary-blue);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 10px;
}

/* CARDS */
.content-card {
  display: flex;
  gap: 16px;
  padding: 20px;
  border-radius: var(--radius-md);
  margin-bottom: 24px;
  border: 1px solid transparent;
}

.alert-summary {
  background-color: #f0f7ff;
  border-color: #bae6fd;
}

.alert-summary .card-icon {
  color: #0284c7;
  font-size: 22px;
  margin-top: 2px;
}

.card-exercise {
  background-color: var(--primary-orange-light);
  border-color: #fed7aa;
}

.icon-orange {
  color: var(--primary-orange-dark);
  font-size: 22px;
  margin-top: 2px;
}

.card-takeaway {
  background-color: var(--success-green-light);
  border-color: #a7f3d0;
}

.icon-green {
  color: var(--success-green);
  font-size: 22px;
  margin-top: 2px;
}

.card-content h3 {
  font-family: var(--font-heading);
  font-size: 15px;
  font-weight: 700;
  margin-bottom: 6px;
  color: var(--text-main);
}

.card-content p {
  font-size: 14px;
  color: #334155;
  line-height: 1.6;
}

.theory-box {
  font-size: 15px;
  color: #334155;
  line-height: 1.7;
}

/* STEPS CONTAINER */
.steps-container {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.step-card {
  display: flex;
  gap: 16px;
  padding: 16px;
  background-color: #f8fafc;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
}

.step-badge {
  width: 32px;
  height: 32px;
  background-color: var(--primary-blue);
  color: #ffffff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 14px;
  flex-shrink: 0;
}

.step-info h4 {
  font-size: 14px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 4px;
}

.step-info p {
  font-size: 13.5px;
  color: var(--text-muted);
  line-height: 1.5;
}

/* PROMPT BOX (THE STAR OF THE LMS) */
.prompt-box-wrapper {
  background-color: #1e293b;
  border-radius: var(--radius-lg);
  border: 1px solid #334155;
  overflow: hidden;
  box-shadow: var(--shadow-md);
}

.prompt-box-header {
  background-color: #0f172a;
  padding: 12px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid #334155;
}

.prompt-box-title {
  color: #f8fafc;
  font-family: var(--font-heading);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.5px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.prompt-box-title i {
  color: var(--primary-orange);
  font-size: 15px;
}

.btn-copy {
  background-color: var(--primary-orange);
  border: none;
  color: #ffffff;
  font-weight: 700;
  font-size: 12px;
  padding: 6px 14px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 6px;
  transition: all 0.2s ease;
}

.btn-copy:hover {
  background-color: var(--primary-orange-dark);
  transform: translateY(-1px);
}

.prompt-box-body {
  padding: 20px;
  max-height: 400px;
  overflow-y: auto;
}

.prompt-text {
  font-family: 'Consolas', 'Monaco', 'Courier New', monospace;
  font-size: 13.5px;
  color: #e2e8f0;
  line-height: 1.6;
  white-space: pre-wrap;
  word-break: break-word;
}

.prompt-box-footer {
  background-color: #0f172a;
  padding: 10px 20px;
  font-size: 12px;
  color: #94a3b8;
  border-top: 1px solid #334155;
}

.prompt-box-footer i {
  color: #38bdf8;
}

/* PERSONAL NOTES */
.note-box {
  background-color: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 14px;
}

.note-box textarea {
  width: 100%;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 10px;
  font-family: inherit;
  font-size: 13.5px;
  color: var(--text-main);
  outline: none;
  resize: vertical;
  transition: border-color 0.2s;
}

.note-box textarea:focus {
  border-color: var(--primary-blue);
}

.note-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 8px;
}

.note-status {
  font-size: 12px;
  color: var(--text-muted);
}

/* LESSON FOOTER NAVIGATION */
.lesson-footer {
  border-top: 1px solid var(--border-color);
  padding-top: 24px;
  margin-top: 40px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.nav-btn {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 20px;
  max-width: 280px;
}

.nav-btn-text {
  display: flex;
  flex-direction: column;
}

.nav-sub {
  font-size: 11px;
  text-transform: uppercase;
  color: var(--text-muted);
  font-weight: 700;
}

.nav-title {
  font-size: 13px;
  font-weight: 700;
  color: var(--text-main);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 200px;
}

.text-right {
  text-align: right;
}

.nav-btn-center {
  padding: 12px 24px;
  font-size: 14px;
  font-weight: 700;
}

/* ========================================================
   5. WELCOME HERO & TRACK OVERVIEW
   ======================================================== */
.welcome-hero {
  max-width: 1000px;
  margin: 0 auto;
}

.hero-card {
  background: linear-gradient(135deg, #2a4094 0%, #1e2e6b 100%);
  color: #ffffff;
  padding: 48px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-xl);
  margin-bottom: 32px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background-color: rgba(247, 148, 29, 0.2);
  border: 1px solid var(--primary-orange);
  color: var(--primary-orange);
  font-size: 12px;
  font-weight: 800;
  padding: 4px 12px;
  border-radius: var(--radius-full);
  margin-bottom: 16px;
}

.hero-title {
  font-family: var(--font-heading);
  font-size: 34px;
  font-weight: 800;
  line-height: 1.25;
  margin-bottom: 16px;
  letter-spacing: -0.5px;
}

.hero-desc {
  font-size: 16px;
  color: #e2e8f0;
  line-height: 1.6;
  max-width: 800px;
  margin-bottom: 28px;
}

.hero-cta-group {
  display: flex;
  gap: 16px;
}

/* TRACKS GRID */
.tracks-quick-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  margin-top: 36px;
}

.track-preview-card {
  background-color: #ffffff;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  padding: 24px;
  cursor: pointer;
  transition: all 0.2s ease;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
}

.track-preview-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--primary-blue);
}

.track-card-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  color: #ffffff;
  margin-bottom: 16px;
}

.track-card-title {
  font-family: var(--font-heading);
  font-size: 17px;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 6px;
}

.track-card-desc {
  font-size: 13px;
  color: var(--text-muted);
  line-height: 1.5;
  margin-bottom: 16px;
  flex: 1;
}

.track-card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 12px;
  font-weight: 700;
  color: var(--primary-blue);
  border-top: 1px solid var(--border-color);
  padding-top: 12px;
}

/* ========================================================
   6. ADMIN DASHBOARD MODAL
   ======================================================== */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background-color: rgba(15, 23, 42, 0.65);
  backdrop-filter: blur(4px);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.modal-card {
  background-color: #ffffff;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-xl);
  display: flex;
  flex-direction: column;
  max-height: 90vh;
  width: 100%;
}

.modal-lg {
  max-width: 1100px;
}

.modal-md {
  max-width: 480px;
}

.modal-header {
  padding: 20px 24px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.modal-header-title {
  display: flex;
  align-items: center;
  gap: 10px;
}

.modal-header-title h2 {
  font-family: var(--font-heading);
  font-size: 18px;
  font-weight: 800;
  color: var(--text-main);
}

.modal-close-btn {
  background: none;
  border: none;
  font-size: 26px;
  color: var(--text-light);
  cursor: pointer;
  line-height: 1;
}

.modal-close-btn:hover {
  color: var(--text-main);
}

.modal-body {
  padding: 24px;
  overflow-y: auto;
  flex: 1;
}

.modal-footer {
  padding: 16px 24px;
  border-top: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: #f8fafc;
  border-bottom-left-radius: var(--radius-lg);
  border-bottom-right-radius: var(--radius-lg);
}

.footer-note {
  font-size: 12px;
  color: var(--text-muted);
}

/* KPI CARDS */
.kpi-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-bottom: 24px;
}

.kpi-card {
  background-color: #f8fafc;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 16px;
  display: flex;
  align-items: center;
  gap: 14px;
}

.kpi-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  color: #ffffff;
  flex-shrink: 0;
}

.icon-blue { background-color: var(--primary-blue); }
.icon-purple { background-color: var(--purple-accent); }

.kpi-info {
  display: flex;
  flex-direction: column;
}

.kpi-value {
  font-family: var(--font-heading);
  font-size: 22px;
  font-weight: 800;
  color: var(--text-main);
  line-height: 1.1;
}

.kpi-label {
  font-size: 11px;
  color: var(--text-muted);
  font-weight: 600;
}

/* ADMIN SECTIONS */
.admin-section {
  background-color: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 20px;
  margin-bottom: 20px;
}

.section-sub-header {
  margin-bottom: 16px;
}

.section-sub-header h3 {
  font-family: var(--font-heading);
  font-size: 15px;
  font-weight: 800;
  color: var(--primary-blue);
  display: flex;
  align-items: center;
  gap: 8px;
}

.section-hint {
  font-size: 12px;
  color: var(--text-muted);
}

.flex-between {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* ADD ADMIN FORM */
.add-admin-form {
  display: flex;
  gap: 10px;
  margin-bottom: 14px;
}

.add-admin-form input {
  flex: 1;
  padding: 10px 14px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  font-size: 13px;
  outline: none;
}

.add-admin-form input:focus {
  border-color: var(--primary-blue);
}

.admin-tags-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.admin-tag-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background-color: #f1f5f9;
  border: 1px solid var(--border-color);
  padding: 6px 12px;
  border-radius: var(--radius-full);
  font-size: 12px;
  font-weight: 600;
  color: var(--text-main);
}

.admin-tag-pill.super {
  background-color: var(--primary-orange-light);
  border-color: var(--primary-orange);
  color: var(--primary-orange-dark);
}

.btn-remove-admin {
  background: none;
  border: none;
  color: var(--text-light);
  cursor: pointer;
  font-size: 13px;
  display: flex;
  align-items: center;
}

.btn-remove-admin:hover {
  color: var(--danger-red);
}

/* ADMIN LEARNERS TABLE */
.table-filter-bar {
  display: flex;
  gap: 12px;
  margin-bottom: 14px;
}

.filter-input-wrap {
  flex: 1;
  display: flex;
  align-items: center;
  gap: 8px;
  background-color: #f8fafc;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 8px 12px;
}

.filter-input-wrap input {
  border: none;
  background: transparent;
  width: 100%;
  font-size: 13px;
  outline: none;
}

.table-filter-bar select {
  padding: 8px 12px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  font-size: 13px;
  background-color: #f8fafc;
  outline: none;
}

.table-responsive {
  overflow-x: auto;
}

.admin-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
  text-align: left;
}

.admin-table th {
  background-color: #f8fafc;
  padding: 10px 14px;
  font-weight: 700;
  color: var(--text-muted);
  border-bottom: 2px solid var(--border-color);
  text-transform: uppercase;
  font-size: 11px;
}

.admin-table td {
  padding: 12px 14px;
  border-bottom: 1px solid var(--border-color);
  vertical-align: middle;
}

.admin-table tr:hover {
  background-color: #f8fafc;
}

.user-cell {
  display: flex;
  align-items: center;
  gap: 10px;
}

.user-cell-name {
  font-weight: 700;
  color: var(--text-main);
}

.user-cell-email {
  font-size: 11px;
  color: var(--text-muted);
}

.table-progress-wrap {
  display: flex;
  align-items: center;
  gap: 8px;
  width: 140px;
}

.table-progress-bar {
  flex: 1;
  height: 6px;
  background-color: #e2e8f0;
  border-radius: var(--radius-full);
  overflow: hidden;
}

.table-progress-fill {
  height: 100%;
  background-color: var(--primary-orange);
  border-radius: var(--radius-full);
}

.table-progress-text {
  font-size: 11px;
  font-weight: 700;
  color: var(--text-muted);
  width: 35px;
}

/* ========================================================
   7. AUTH / LOGIN MODAL
   ======================================================== */
.auth-modal-logo {
  height: 50px;
  margin-bottom: 16px;
}

.auth-intro {
  font-size: 13.5px;
  color: var(--text-muted);
  line-height: 1.5;
  margin-bottom: 20px;
}

.google-gis-container {
  display: flex;
  justify-content: center;
  margin-bottom: 16px;
}

.auth-divider {
  display: flex;
  align-items: center;
  text-align: center;
  margin: 18px 0;
  color: var(--text-light);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.5px;
}

.auth-divider::before,
.auth-divider::after {
  content: '';
  flex: 1;
  border-bottom: 1px solid var(--border-color);
}

.auth-divider span {
  padding: 0 10px;
}

.auth-form {
  text-align: left;
}

.form-group {
  margin-bottom: 14px;
}

.form-group label {
  display: block;
  font-size: 12px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 6px;
}

.input-with-icon {
  display: flex;
  align-items: center;
  background-color: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 9px 12px;
  gap: 8px;
}

.input-with-icon input {
  border: none;
  background: transparent;
  width: 100%;
  font-size: 13px;
  outline: none;
}

.form-select {
  width: 100%;
  padding: 9px 12px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  font-size: 13px;
  outline: none;
  background-color: #ffffff;
}

.quick-demo-accounts {
  margin-top: 20px;
  padding-top: 16px;
  border-top: 1px solid var(--border-color);
  text-align: left;
}

.quick-demo-title {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-muted);
  display: block;
  margin-bottom: 8px;
}

.quick-tags {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.quick-tag {
  background-color: #f1f5f9;
  border: 1px solid var(--border-color);
  padding: 7px 12px;
  border-radius: var(--radius-md);
  font-size: 12px;
  font-weight: 600;
  color: var(--text-main);
  cursor: pointer;
  text-align: left;
  display: flex;
  align-items: center;
  gap: 8px;
  transition: all 0.15s;
}

.quick-tag:hover {
  background-color: var(--primary-blue-light);
  border-color: var(--primary-blue);
  color: var(--primary-blue);
}

.quick-tag.tag-admin {
  background-color: var(--primary-orange-light);
  border-color: #fed7aa;
  color: var(--primary-orange-dark);
}

.quick-tag.tag-admin:hover {
  border-color: var(--primary-orange);
}

/* ========================================================
   8. COMMON BUTTONS & UTILITIES
   ======================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: inherit;
  font-weight: 700;
  font-size: 13px;
  border-radius: var(--radius-md);
  padding: 8px 16px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.2s ease;
  text-decoration: none;
}

.btn-primary {
  background-color: var(--primary-blue);
  color: #ffffff;
}

.btn-primary:hover {
  background-color: var(--primary-blue-dark);
}

.btn-secondary {
  background-color: #ffffff;
  border-color: var(--border-color);
  color: var(--text-main);
}

.btn-secondary:hover {
  background-color: #f1f5f9;
}

.btn-success {
  background-color: var(--success-green);
  color: #ffffff;
}

.btn-success:hover {
  background-color: #059669;
}

.btn-outline-success {
  background-color: var(--success-green-light);
  border-color: var(--success-green);
  color: var(--success-green);
}

.btn-outline-success:hover {
  background-color: var(--success-green);
  color: #ffffff;
}

.btn-block {
  width: 100%;
}

.btn-lg {
  padding: 12px 24px;
  font-size: 15px;
}

.btn-sm {
  padding: 6px 12px;
  font-size: 12px;
}

.icon-btn {
  background: none;
  border: none;
  font-size: 20px;
  color: var(--text-main);
  cursor: pointer;
  padding: 4px;
}

.mobile-only {
  display: none;
}

/* TOAST NOTIFICATION */
.toast-container {
  position: fixed;
  bottom: 24px;
  right: 24px;
  z-index: 2000;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.toast {
  background-color: #0f172a;
  color: #ffffff;
  padding: 12px 20px;
  border-radius: var(--radius-md);
  font-size: 13.5px;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 10px;
  box-shadow: var(--shadow-xl);
  animation: slideIn 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.toast.success { border-left: 4px solid var(--success-green); }
.toast.info { border-left: 4px solid #38bdf8; }
.toast.warning { border-left: 4px solid var(--primary-orange); }

@keyframes slideIn {
  from { transform: translateX(100%); opacity: 0; }
  to { transform: translateX(0); opacity: 1; }
}

/* ========================================================
   9. RESPONSIVE BREAKPOINTS
   ======================================================== */
@media (max-width: 1024px) {
  .nav-center { display: none; }
  .content-workspace { padding: 20px; }
  .lesson-viewer { padding: 24px; }
  .kpi-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .mobile-only { display: block; }
  .sidebar {
    position: fixed;
    top: var(--header-height);
    left: -100%;
    bottom: 0;
    z-index: 90;
    width: 320px;
    transition: left 0.3s ease;
    box-shadow: var(--shadow-xl);
  }
  .sidebar.open {
    left: 0;
  }
  .brand-sub { display: none; }
  .user-email { display: none; }
  .lesson-title { font-size: 20px; }
  .lesson-title-row { flex-direction: column; }
  .lesson-footer { flex-direction: column; }
  .nav-btn { width: 100%; max-width: none; }
  .kpi-grid { grid-template-columns: 1fr; }
}

/* ========================================================
   10. TỐI ƯU CHO ĐIỆN THOẠI
   ======================================================== */
html { -webkit-text-size-adjust: 100%; }
img { max-width: 100%; }
.lesson-viewer, .content-workspace, .hero-card { min-width: 0; }
.prompt-text, .theory-box, .card-content p, .lesson-title { overflow-wrap: anywhere; }

@media (max-width: 768px) {
  :root { --header-height: 60px; }
  body { overflow-x: hidden; }

  .top-nav { padding: 0 10px; gap: 8px; }
  .nav-left { gap: 8px; min-width: 0; }
  .brand-logo { height: 34px; }
  .brand-title { font-size: 14px; white-space: nowrap; }
  .nav-right { gap: 8px; flex-shrink: 0; }

  /* Rút gọn các khối ở thanh trên cho vừa màn hình nhỏ */
  .progress-pill { padding: 4px 8px; }
  .progress-pill-info { display: none; }
  .btn-outline-admin span:not(.admin-badge) { display: none; }
  .btn-outline-admin { padding: 7px 10px; }
  .admin-badge { display: none; }
  .user-meta { display: none; }
  .logged-user-pill { padding: 3px 6px; gap: 6px; }
  #login-trigger-btn { padding: 8px 12px; font-size: 12px; }
  #login-trigger-btn span { white-space: nowrap; }

  .app-layout { height: calc(100dvh - var(--header-height)); }
  .sidebar { width: 88vw; max-width: 340px; }

  .content-workspace { padding: 12px; }
  .lesson-viewer { padding: 18px 16px; border-radius: 12px; }
  .lesson-title { font-size: 20px; }
  .section-title { font-size: 16px; }
  .btn-complete { width: 100%; justify-content: center; }
  .lesson-actions { width: 100%; }

  .hero-card { padding: 24px 18px; }
  .hero-title { font-size: 24px; }
  .hero-desc { font-size: 14px; }
  .hero-cta-group { flex-direction: column; }
  .hero-cta-group .btn { width: 100%; }
  .tracks-quick-grid { grid-template-columns: 1fr; }

  .prompt-box-header { flex-direction: column; align-items: stretch; gap: 10px; padding: 12px; }
  .btn-copy { width: 100%; justify-content: center; padding: 10px; }
  .prompt-box-body { padding: 14px; }
  .prompt-text { font-size: 12.5px; }

  .step-card { padding: 12px; gap: 12px; }
  .content-card { padding: 14px; gap: 12px; }

  .lesson-footer { flex-direction: column-reverse; }
  .nav-btn, .nav-btn-center { width: 100%; max-width: none; justify-content: center; }
  .nav-title { max-width: 60vw; }

  /* Bảng quản trị */
  .modal-backdrop { padding: 0; align-items: flex-end; }
  .modal-card { max-height: 94dvh; border-radius: 16px 16px 0 0; }
  .modal-body { padding: 14px; }
  .modal-footer { flex-direction: column; gap: 8px; align-items: stretch; }
  .flex-between { flex-direction: column; align-items: stretch; gap: 10px; }
  .add-admin-form { flex-direction: column; }
  .table-filter-bar { flex-direction: column; }
  .admin-table { min-width: 640px; }
  .kpi-grid { grid-template-columns: 1fr 1fr; gap: 10px; }
  .kpi-card { padding: 10px; gap: 8px; }
  .kpi-value { font-size: 18px; }
  .kpi-icon { width: 34px; height: 34px; font-size: 15px; }
}

@media (max-width: 380px) {
  .brand-title { font-size: 12.5px; }
  .brand-logo { height: 28px; }
}

/* Ô nhập: cỡ chữ 16px để iPhone không tự phóng to khi bấm vào */
@media (max-width: 768px) {
  input, select, textarea { font-size: 16px !important; }
}

/* ========================================================
   11. THANH CHỌN BÀI CỦA LỘ TRÌNH VỊ TRÍ (TRONG KHUNG BÀI HỌC)
   ======================================================== */
.role-lessons-bar {
  background-color: #f8fafc;
  border: 1px solid var(--border-color);
  border-left: 4px solid var(--primary-orange);
  border-radius: var(--radius-md);
  padding: 14px 16px;
  margin-bottom: 24px;
}

.role-lessons-bar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 12px;
  flex-wrap: wrap;
}

.role-lessons-bar-title {
  font-family: var(--font-heading);
  font-size: 13.5px;
  font-weight: 700;
  color: var(--primary-blue);
  display: flex;
  align-items: center;
  gap: 8px;
}

.role-lessons-bar-title i {
  color: var(--primary-orange);
}

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

.role-lesson-pill {
  background-color: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 7px 11px;
  font-size: 12.5px;
  font-weight: 500;
  color: var(--text-main);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  text-align: left;
  transition: all 0.15s ease;
  max-width: 100%;
}

.role-lesson-pill:hover {
  border-color: var(--primary-blue);
  color: var(--primary-blue);
  background-color: #f0f4ff;
}

.role-lesson-pill.active {
  background-color: var(--primary-blue);
  border-color: var(--primary-blue);
  color: #ffffff;
  font-weight: 700;
}

.role-lesson-pill.completed i {
  color: var(--success-green);
}

.role-lesson-pill.active.completed i {
  color: #ffffff;
}