:root {
  --primary: #4F46E5;
  --primary-hover: #4338CA;
  --secondary: #6B7280;
  --secondary-hover: #4B5563;
  --success: #10B981;
  --success-hover: #059669;
  --danger: #EF4444;
  --bg-color: #F3F4F6;
  --card-bg: #FFFFFF;
  --text-main: #111827;
  --text-muted: #6B7280;
  --border-color: #E5E7EB;
  --radius: 12px;
  --shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

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

body {
  font-family: 'Inter', sans-serif;
  background-color: var(--bg-color);
  color: var(--text-main);
  line-height: 1.5;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

#app {
  width: 100%;
  max-width: 800px;
  min-height: 90vh;
  display: flex;
  flex-direction: column;
  padding: 20px;
}

.hidden {
  display: none !important;
}

/* Header */
.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2rem;
  padding: 1rem 1.5rem;
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
}

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

.header-logo h1 {
  font-size: 1.25rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--primary), #8B5CF6);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.logo-icon {
  font-size: 1.5rem;
}

#user-info-display {
  display: flex;
  align-items: center;
  gap: 15px;
  font-weight: 500;
}

/* Cards */
.card {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 2rem;
  box-shadow: var(--shadow);
  animation: fadeIn 0.4s ease-out;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Forms */
.form-group {
  margin-bottom: 1.5rem;
}

.form-group label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 500;
  color: var(--text-main);
}

.form-group input {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  font-size: 1rem;
  font-family: inherit;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.form-group input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.2);
}

.action-buttons {
  display: flex;
  gap: 1rem;
  margin-top: 2rem;
}

.mt-4 { margin-top: 1rem; }

.error-msg {
  color: var(--danger);
  margin-top: 1rem;
  font-size: 0.875rem;
  background: #FEF2F2;
  padding: 0.75rem;
  border-radius: 8px;
  border-left: 4px solid var(--danger);
}

/* Buttons */
.btn {
  display: inline-flex;
  justify-content: center;
  align-items: center;
  padding: 0.75rem 1.5rem;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
  font-family: inherit;
}

.btn-sm {
  padding: 0.4rem 0.8rem;
  font-size: 0.875rem;
}

.btn-primary {
  background-color: var(--primary);
  color: white;
}

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

.btn-secondary {
  background-color: #E5E7EB;
  color: var(--text-main);
}

.btn-secondary:hover {
  background-color: #D1D5DB;
}

.btn-success {
  background-color: var(--success);
  color: white;
}

.btn-success:hover {
  background-color: var(--success-hover);
}

.btn-outline {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-main);
}

.btn-outline:hover {
  background: var(--bg-color);
}

.btn-block {
  width: 100%;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

/* Dashboard */
.course-options {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  margin-top: 2rem;
}

@media (max-width: 600px) {
  .course-options {
    grid-template-columns: 1fr;
  }
}

.course-card {
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1.5rem;
  text-align: center;
  transition: transform 0.2s, box-shadow 0.2s;
}

.course-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow);
  border-color: var(--primary);
}

.course-icon {
  font-size: 3rem;
  margin-bottom: 1rem;
}

.course-card h3 {
  margin-bottom: 0.5rem;
}

.course-card p {
  color: var(--text-muted);
  font-size: 0.875rem;
  margin-bottom: 1rem;
}

.course-meta {
  font-weight: 600;
  color: var(--primary) !important;
  background: #EEF2FF;
  padding: 0.25rem 0.5rem;
  border-radius: 6px;
  display: inline-block;
}

/* Exam Active */
.exam-header-status {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 1rem;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
}

.exam-title-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}

.timer {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary);
  background: #EEF2FF;
  padding: 0.5rem 1rem;
  border-radius: 8px;
  font-variant-numeric: tabular-nums;
}

.timer.warning {
  color: var(--danger);
  background: #FEF2F2;
  animation: pulse 1s infinite;
}

@keyframes pulse {
  0% { opacity: 1; }
  50% { opacity: 0.5; }
  100% { opacity: 1; }
}

.progress-bar-container {
  height: 8px;
  background: var(--bg-color);
  border-radius: 4px;
  overflow: hidden;
  margin-bottom: 0.5rem;
}

.progress-bar {
  height: 100%;
  background: var(--success);
  width: 0%;
  transition: width 0.3s ease;
}

.question-status {
  font-size: 0.875rem;
  color: var(--text-muted);
  text-align: right;
}

.question-card {
  min-height: 300px;
}

.question-text {
  font-size: 1.25rem;
  margin-bottom: 2rem;
  line-height: 1.4;
}

.options-container {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.option-label {
  display: flex;
  align-items: center;
  padding: 1rem 1.5rem;
  border: 2px solid var(--border-color);
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.2s;
  font-weight: 500;
}

.option-label:hover {
  border-color: var(--primary);
  background: #EEF2FF;
}

.option-label input {
  margin-right: 1rem;
  width: 1.2rem;
  height: 1.2rem;
  accent-color: var(--primary);
}

.option-label.selected {
  border-color: var(--primary);
  background: #EEF2FF;
}

.exam-navigation {
  display: flex;
  justify-content: space-between;
  margin-top: 1.5rem;
}

/* Result View */
.result-card {
  text-align: center;
  padding: 3rem 2rem;
}

.score-circle {
  width: 150px;
  height: 150px;
  border-radius: 50%;
  background: conic-gradient(var(--primary) 0%, var(--bg-color) 0%);
  display: flex;
  justify-content: center;
  align-items: center;
  margin: 2rem auto;
  position: relative;
  box-shadow: inset 0 0 20px rgba(0,0,0,0.05);
}

.score-circle::before {
  content: "";
  position: absolute;
  inset: 10px;
  background: var(--card-bg);
  border-radius: 50%;
}

.score-circle span {
  position: relative;
  z-index: 1;
}

.score-text {
  font-size: 3rem;
  font-weight: 700;
  color: var(--primary);
}

.score-divider {
  font-size: 2rem;
  color: var(--secondary);
  margin: 0 0.25rem;
}

.score-total {
  font-size: 1.5rem;
  color: var(--secondary);
  margin-top: 1rem;
}

.result-message {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 2rem;
}

.result-details {
  background: var(--bg-color);
  padding: 1.5rem;
  border-radius: 12px;
  text-align: left;
  max-width: 400px;
  margin: 0 auto 2rem;
}

.result-details p {
  margin-bottom: 0.5rem;
  display: flex;
  justify-content: space-between;
}

/* Past Results */
.past-result-item {
  background: var(--bg-color);
  padding: 1rem 1.5rem;
  border-radius: 8px;
  margin-bottom: 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-left: 4px solid var(--primary);
}

.past-result-info h4 {
  margin-bottom: 0.25rem;
}

.past-result-info p {
  font-size: 0.875rem;
  color: var(--text-muted);
}

.past-result-score {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary);
}