/* Intelligrade Lite — Digital Exam Platform Styles */

:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --accent: #0ea5e9;
  --danger: #dc2626;
  --success: #16a34a;
  --warning: #ca8a04;
  --bg: #f8fafc;
  --card: #ffffff;
  --text: #1e293b;
  --text-muted: #64748b;
  --border: #e2e8f0;
  --radius: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,0.1);
  --shadow-lg: 0 4px 12px rgba(0,0,0,0.1);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
}

/* Navigation */
.nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
  background: var(--card);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav-brand {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--primary);
  cursor: pointer;
}

.nav-links { display: flex; gap: 0.5rem; }

.nav-btn {
  padding: 0.5rem 1rem;
  border: none;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  border-radius: var(--radius);
  font-size: 0.875rem;
  transition: all 0.2s;
}

.nav-btn:hover, .nav-btn.active {
  background: var(--bg);
  color: var(--primary);
}

/* Container */
.container {
  max-width: 960px;
  margin: 0 auto;
  padding: 2rem 1rem;
}

/* Hero */
.hero {
  text-align: center;
  padding: 3rem 1rem;
  margin-bottom: 2rem;
}

.hero h1 {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
  color: var(--text);
}

.hero p {
  color: var(--text-muted);
  font-size: 1.1rem;
  max-width: 600px;
  margin: 0 auto 1.5rem;
}

/* Buttons */
.btn {
  padding: 0.5rem 1rem;
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text);
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 0.875rem;
  transition: all 0.2s;
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
}

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

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

.btn-accent {
  background: var(--accent);
  color: white;
  border-color: var(--accent);
}
.btn-accent:hover { background: #0284c7; }

.btn-danger {
  background: var(--danger);
  color: white;
  border-color: var(--danger);
}
.btn-danger:hover { background: #b91c1c; }

.btn-sm { padding: 0.25rem 0.5rem; font-size: 0.75rem; }
.btn-large { padding: 0.75rem 1.5rem; font-size: 1rem; }
.btn-back { margin-bottom: 1rem; }
.btn-icon {
  width: 28px;
  height: 28px;
  padding: 0;
  justify-content: center;
  font-size: 1rem;
}

/* Stats */
.stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1rem;
  margin-bottom: 2rem;
}

.stat-card {
  background: var(--card);
  padding: 1.5rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  text-align: center;
}

.stat-value {
  font-size: 2rem;
  font-weight: 700;
  color: var(--primary);
}

.stat-label {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
}

/* Exam Grid */
.exam-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1rem;
  margin-bottom: 2rem;
}

.exam-card {
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
}

.exam-card-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 0.5rem;
}

.exam-card-header h3 {
  font-size: 1.1rem;
  font-weight: 600;
}

.badge {
  background: var(--bg);
  color: var(--text-muted);
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
  font-size: 0.75rem;
}

.exam-subject {
  color: var(--primary);
  font-size: 0.875rem;
  font-weight: 500;
  margin-bottom: 0.25rem;
}

.exam-desc {
  color: var(--text-muted);
  font-size: 0.875rem;
  margin-bottom: 1rem;
  flex-grow: 1;
}

.exam-meta {
  display: flex;
  gap: 1rem;
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-bottom: 1rem;
}

.exam-actions {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

/* Submission List */
.submission-list {
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.submission-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.875rem 1rem;
  border-bottom: 1px solid var(--border);
  gap: 1rem;
}

.submission-row:last-child { border-bottom: none; }

.sub-student { font-weight: 500; min-width: 120px; }
.sub-exam { color: var(--text-muted); font-size: 0.875rem; flex-grow: 1; }
.sub-score { font-weight: 600; color: var(--primary); }
.sub-status {
  font-size: 0.75rem;
  padding: 0.125rem 0.5rem;
  border-radius: 4px;
  background: var(--bg);
  color: var(--text-muted);
}
.sub-status.graded { background: #dcfce7; color: var(--success); }
.sub-status.pending { background: #fef9c3; color: var(--warning); }
.sub-date { font-size: 0.75rem; color: var(--text-muted); }

/* Empty State */
.empty-state {
  text-align: center;
  padding: 3rem;
  color: var(--text-muted);
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

/* Editor */
.editor-header {
  margin-bottom: 1.5rem;
}

.editor-header h1 {
  font-size: 1.5rem;
  margin-top: 0.5rem;
}

.editor-form {
  background: var(--card);
  padding: 1.5rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  margin-bottom: 1.5rem;
}

.form-group { margin-bottom: 1rem; }
.form-group label {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
  margin-bottom: 0.375rem;
  color: var(--text);
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 0.625rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 0.875rem;
  background: var(--bg);
  color: var(--text);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--primary);
}

.form-row {
  display: flex;
  gap: 1rem;
}
.form-row .form-group { flex: 1; }
.flex-grow { flex-grow: 1; }

.form-checkboxes {
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.form-checkboxes label {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.875rem;
  cursor: pointer;
}

/* Question Editor */
.question-editor {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem;
  margin-bottom: 1rem;
}

.question-header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.75rem;
}

.question-number {
  background: var(--primary);
  color: white;
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  font-size: 0.75rem;
  font-weight: 600;
}

.question-type-badge {
  background: var(--card);
  padding: 0.125rem 0.5rem;
  border-radius: 4px;
  font-size: 0.75rem;
  text-transform: capitalize;
  color: var(--text-muted);
  flex-grow: 1;
}

.options-list { margin: 0.5rem 0; }
.option-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
}
.option-row input[type="radio"] { margin-right: 0.25rem; }
.option-text { flex-grow: 1; }

.add-question-bar {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-bottom: 1.5rem;
}

.editor-actions {
  display: flex;
  justify-content: flex-end;
  gap: 1rem;
  margin-top: 1rem;
}

/* Take Exam */
.take-header {
  background: var(--card);
  padding: 1.5rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  margin-bottom: 1.5rem;
}

.take-header h1 { font-size: 1.5rem; margin-bottom: 0.5rem; }

.take-meta {
  display: flex;
  gap: 1rem;
  color: var(--text-muted);
  font-size: 0.875rem;
}

.timer {
  font-weight: 600;
  color: var(--danger);
}

.student-form {
  background: var(--card);
  padding: 1rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  margin-bottom: 1rem;
}

.questions-list { margin-bottom: 1rem; }

.question-take {
  background: var(--card);
  padding: 1.5rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  margin-bottom: 1rem;
}

.question-text {
  font-weight: 500;
  margin-bottom: 1rem;
  font-size: 1rem;
}

.question-text .points {
  color: var(--text-muted);
  font-weight: 400;
  font-size: 0.875rem;
}

.options-take { display: flex; flex-direction: column; gap: 0.5rem; }

.option-label {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  cursor: pointer;
  transition: all 0.2s;
}

.option-label:hover { background: var(--bg); }
.option-label input { margin-right: 0.5rem; }

.answer-input,
.answer-textarea {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 0.875rem;
  background: var(--bg);
}

.answer-textarea { resize: vertical; min-height: 100px; }

.take-actions {
  display: flex;
  justify-content: center;
  padding: 1rem 0;
}

/* Grade */
.grade-exam-title {
  color: var(--text-muted);
  font-size: 0.875rem;
}

.grade-summary {
  background: var(--card);
  padding: 1rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  margin-bottom: 1rem;
  text-align: center;
}

.grade-score {
  font-size: 1.25rem;
  font-weight: 600;
}

.questions-grade { margin-bottom: 1rem; }

.question-grade {
  background: var(--card);
  padding: 1rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  margin-bottom: 1rem;
}

.answer-display {
  background: var(--bg);
  padding: 0.75rem;
  border-radius: var(--radius);
  margin: 0.5rem 0;
  font-size: 0.875rem;
}

.correct-answer {
  color: var(--success);
  font-size: 0.875rem;
  margin-bottom: 0.5rem;
}

.grade-input {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-top: 0.5rem;
}

.grade-input input {
  width: 80px;
  padding: 0.5rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.auto-badge {
  font-size: 0.75rem;
  padding: 0.125rem 0.5rem;
  border-radius: 4px;
  background: var(--bg);
  color: var(--text-muted);
}
.auto-badge.auto { background: #dcfce7; color: var(--success); }
.auto-badge.manual { background: #fef9c3; color: var(--warning); }

/* Results */
.question-breakdown { margin-top: 1rem; }

.breakdown-row {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--border);
}

.breakdown-text {
  flex: 0 0 200px;
  font-size: 0.875rem;
}

.breakdown-bar {
  flex-grow: 1;
  height: 8px;
  background: var(--bg);
  border-radius: 4px;
  overflow: hidden;
}

.breakdown-fill {
  height: 100%;
  background: var(--primary);
  border-radius: 4px;
  transition: width 0.3s;
}

.breakdown-score {
  font-size: 0.875rem;
  color: var(--text-muted);
  min-width: 60px;
  text-align: right;
}

/* Export */
.export-section {
  background: var(--card);
  padding: 1.5rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  margin-bottom: 1rem;
}

.export-section h2 { font-size: 1.1rem; margin-bottom: 0.5rem; }
.export-section p { color: var(--text-muted); font-size: 0.875rem; margin-bottom: 1rem; }

/* Responsive */
@media (max-width: 640px) {
  .nav { padding: 1rem; }
  .container { padding: 1rem; }
  .hero { padding: 2rem 1rem; }
  .hero h1 { font-size: 1.75rem; }
  .exam-grid { grid-template-columns: 1fr; }
  .form-row { flex-direction: column; gap: 0; }
  .submission-row { flex-direction: column; align-items: flex-start; gap: 0.25rem; }
  .breakdown-row { flex-direction: column; align-items: flex-start; gap: 0.5rem; }
  .breakdown-text { flex: none; }
  .breakdown-bar { width: 100%; }
}