:root {
  --bg-deep: #08090c;
  --bg-primary: #0c0e14;
  --bg-card: #12151e;
  --bg-card-hover: #181c28;
  --bg-input: #0c0e14;
  --border: #1e2230;
  --border-hover: #2a2f42;
  --border-focus: var(--accent);
  --text-primary: #e2e4ec;
  --text-secondary: #7e8399;
  --text-muted: #444966;
  --accent: #e8a838;
  --accent-dim: rgba(232, 168, 56, 0.12);
  --accent-glow: rgba(232, 168, 56, 0.06);
  --success: #34d399;
  --success-dim: rgba(52, 211, 153, 0.12);
  --warning: #e8a838;
  --warning-dim: rgba(232, 168, 56, 0.12);
  --error: #ef5f5f;
  --error-dim: rgba(239, 95, 95, 0.12);
  --cyan: #5ce0d8;
  --cyan-dim: rgba(92, 224, 216, 0.12);
  --font-display: "Sora", sans-serif;
  --font-mono: "IBM Plex Mono", "SF Mono", monospace;
  --font-body: "Sora", sans-serif;
  --radius: 10px;
  --radius-sm: 6px;
}

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

body {
  font-family: var(--font-body);
  background: var(--bg-deep);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
}

/* --- Grain overlay --- */

.grain {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 9999;
  opacity: 0.03;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)'/%3E%3C/svg%3E");
  background-repeat: repeat;
  background-size: 256px;
}

a { color: var(--accent); text-decoration: none; transition: color 0.2s; }
a:hover { color: #f0be5e; text-decoration: none; }

/* --- Layout --- */

.shell {
  display: grid;
  grid-template-columns: 200px 1fr;
  min-height: 100vh;
}

@media (max-width: 1024px) {
  main { padding: 24px; }
  .card-grid { grid-template-columns: 1fr; }
}

@media (max-width: 768px) {
  .shell { grid-template-columns: 1fr; }
  nav {
    flex-direction: row;
    padding: 10px 16px;
    border-bottom: 1px solid var(--border);
    border-right: none;
    height: auto;
    position: static;
    overflow-x: auto;
  }
  nav .nav-links { flex-direction: row; gap: 2px; flex-wrap: nowrap; }
  nav .nav-links a { padding: 8px 10px; font-size: 12px; white-space: nowrap; }
  nav .brand { margin-bottom: 0; }
  nav .nav-footer { display: none; }
  main { padding: 16px; }
  h1 { font-size: 22px; margin-bottom: 20px; }
  .stats-bar { grid-template-columns: repeat(2, 1fr); gap: 8px; }
  .stat-card .value { font-size: 24px; }
  .cal-grid { font-size: 10px; }
  .cal-cell { min-height: 60px; padding: 4px; }
  table { font-size: 12px; }
  th, td { padding: 8px 6px; }
}

@media (max-width: 480px) {
  .stats-bar { grid-template-columns: 1fr 1fr; }
  .module-header { padding: 12px; flex-wrap: wrap; gap: 8px; }
  .card { padding: 16px; }
}

/* --- Nav --- */

nav {
  display: flex;
  flex-direction: column;
  padding: 24px 16px 16px;
  border-right: 1px solid var(--border);
  background: var(--bg-primary);
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
}

nav .brand {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 36px;
  padding: 0 8px;
}

.brand-name {
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.03em;
}

.nav-links {
  display: flex;
  flex-direction: column;
  gap: 2px;
  list-style: none;
  flex: 1;
}

.nav-links a {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border-radius: var(--radius-sm);
  color: var(--text-muted);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.01em;
  transition: all 0.2s ease;
}

.nav-links a:hover { background: var(--bg-card); color: var(--text-secondary); }
.nav-links a.active {
  background: var(--accent-dim);
  color: var(--accent);
  box-shadow: inset 3px 0 0 var(--accent);
}
.nav-links a.active svg { color: var(--accent); }

.nav-footer {
  margin-top: auto;
  padding: 12px 8px 0;
  border-top: 1px solid var(--border);
}

.nav-footer-label {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-muted);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

/* --- Main --- */

main {
  padding: 40px 48px;
  max-width: 1100px;
  overflow-y: auto;
}

h1 {
  font-family: var(--font-display);
  font-size: 26px;
  font-weight: 700;
  margin-bottom: 28px;
  letter-spacing: -0.03em;
  color: var(--text-primary);
}

h2 {
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 16px;
  color: var(--text-secondary);
  letter-spacing: -0.01em;
  text-transform: uppercase;
  font-size: 12px;
  letter-spacing: 0.08em;
}

h3 {
  font-family: var(--font-display);
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 10px;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

/* --- Entrance animations --- */

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes glowPulse {
  0%, 100% { box-shadow: 0 0 0 0 var(--accent-glow); }
  50% { box-shadow: 0 0 20px 2px var(--accent-glow); }
}

.stats-bar, .card-grid, .section, .module-card, .alert, .chart-container, table {
  animation: fadeUp 0.4s ease both;
}

.stats-bar { animation-delay: 0.05s; }
.card-grid { animation-delay: 0.15s; }

/* --- Stats bar --- */

.stats-bar {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 12px;
  margin-bottom: 32px;
}

.stat-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  position: relative;
  overflow: hidden;
  transition: border-color 0.3s, box-shadow 0.3s;
}

.stat-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--border);
  transition: background 0.3s;
}

.stat-card:hover { border-color: var(--border-hover); }

.stat-card .label {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 8px;
}

.stat-card .value {
  font-family: var(--font-mono);
  font-size: 32px;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.stat-card .value.accent { color: var(--accent); }
.stat-card:has(.value.accent)::before { background: var(--accent); }
.stat-card .value.success { color: var(--success); }
.stat-card:has(.value.success)::before { background: var(--success); }
.stat-card .value.warning { color: var(--warning); }
.stat-card:has(.value.warning)::before { background: var(--warning); }
.stat-card .value.error { color: var(--error); }
.stat-card:has(.value.error)::before { background: var(--error); }

/* --- Cards --- */

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 16px;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition: border-color 0.25s, transform 0.25s, box-shadow 0.25s;
  position: relative;
}

.card:hover {
  border-color: var(--border-hover);
  transform: translateY(-2px);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

.card-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 14px;
}

.card-title {
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 600;
  letter-spacing: -0.02em;
}

.card-meta {
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 12px;
}

.card-actions {
  display: flex;
  gap: 8px;
  margin-top: 18px;
}

/* --- Badges --- */

.badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.badge-blue { background: var(--cyan-dim); color: var(--cyan); }
.badge-green { background: var(--success-dim); color: var(--success); }
.badge-yellow { background: var(--warning-dim); color: var(--accent); }
.badge-red { background: var(--error-dim); color: var(--error); }

/* --- Buttons --- */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-card);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s ease;
  letter-spacing: 0.01em;
}

.btn:hover { border-color: var(--border-hover); background: var(--bg-card-hover); transform: translateY(-1px); }
.btn-primary {
  background: var(--accent);
  color: var(--bg-deep);
  border-color: var(--accent);
  font-weight: 600;
}
.btn-primary:hover { background: #f0be5e; box-shadow: 0 4px 16px rgba(232, 168, 56, 0.25); }
.btn-danger { color: var(--error); border-color: var(--error-dim); }
.btn-danger:hover { background: var(--error-dim); border-color: var(--error); }
.btn-sm { padding: 5px 12px; font-size: 12px; }

/* --- Progress bar --- */

.progress-bar {
  display: flex;
  height: 4px;
  background: var(--border);
  border-radius: 2px;
  overflow: hidden;
  margin: 10px 0;
}

.progress-bar .fill {
  background: linear-gradient(90deg, var(--accent), #f0be5e);
  border-radius: 2px;
  transition: width 0.6s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: 0 0 8px var(--accent-glow);
}

/* --- Tables --- */

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
}

th {
  text-align: left;
  padding: 12px 14px;
  border-bottom: 1px solid var(--border);
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-weight: 600;
}

td {
  padding: 12px 14px;
  border-bottom: 1px solid var(--border);
  color: var(--text-secondary);
}

tr { transition: background 0.15s; }
tr:hover td { background: var(--bg-card-hover); }

/* --- Module cards (plan view) --- */

.module-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 10px;
  overflow: hidden;
  transition: border-color 0.2s;
  animation: fadeUp 0.3s ease both;
}

.module-card:nth-child(1) { animation-delay: 0.05s; }
.module-card:nth-child(2) { animation-delay: 0.1s; }
.module-card:nth-child(3) { animation-delay: 0.15s; }
.module-card:nth-child(4) { animation-delay: 0.2s; }
.module-card:nth-child(5) { animation-delay: 0.25s; }

.module-card:hover { border-color: var(--border-hover); }

.module-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 20px;
  cursor: pointer;
  user-select: none;
  transition: background 0.15s;
}

.module-header:hover { background: var(--bg-card-hover); }

.module-body {
  padding: 16px 20px 20px;
  display: none;
  animation: fadeUp 0.25s ease both;
}

.module-body ul { padding-left: 20px; margin-bottom: 8px; }
.module-body li { margin-bottom: 4px; }

.module-card.open .module-body { display: block; }
.module-card.open .module-header { border-bottom: 1px solid var(--border); }
.module-card.open { border-color: var(--accent); border-color: rgba(232, 168, 56, 0.3); }

.module-num {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-muted);
  min-width: 24px;
  background: var(--accent-dim);
  color: var(--accent);
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 6px;
  font-weight: 600;
}

.concept-tag {
  display: inline-block;
  padding: 4px 10px;
  margin: 3px 4px 3px 0;
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 11px;
  background: var(--cyan-dim);
  color: var(--cyan);
  border: 1px solid rgba(92, 224, 216, 0.15);
  transition: background 0.15s;
}

.concept-tag:hover { background: rgba(92, 224, 216, 0.18); }

.resource-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 0;
  font-size: 13px;
  border-bottom: 1px solid var(--border);
}

.resource-item:last-child { border-bottom: none; }

.resource-type {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  min-width: 56px;
  padding: 2px 6px;
  background: var(--bg-primary);
  border-radius: 3px;
  text-align: center;
}

/* --- Calendar --- */

.cal-grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.cal-header {
  background: var(--bg-card);
  padding: 10px;
  text-align: center;
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-muted);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.cal-cell {
  background: var(--bg-primary);
  min-height: 88px;
  padding: 8px;
  font-size: 12px;
  transition: background 0.15s;
}

.cal-cell:hover { background: var(--bg-card-hover); }
.cal-cell.empty { background: var(--bg-card); opacity: 0.25; }
.cal-cell.today {
  box-shadow: inset 0 0 0 2px var(--accent);
  background: var(--accent-glow);
}

.cal-date {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  color: var(--text-muted);
  margin-bottom: 6px;
}

.cal-cell.today .cal-date { color: var(--accent); font-weight: 600; }

.cal-item {
  font-family: var(--font-mono);
  font-size: 10px;
  padding: 2px 6px;
  margin: 2px 0;
  border-radius: 3px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  cursor: default;
  letter-spacing: 0.02em;
}

.cal-item.overdue { background: var(--error-dim); color: var(--error); }
.cal-item.upcoming { background: var(--cyan-dim); color: var(--cyan); }

/* --- Forms --- */

input, select, textarea {
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 10px 14px;
  color: var(--text-primary);
  font-size: 14px;
  font-family: var(--font-body);
  width: 100%;
  transition: border-color 0.2s, box-shadow 0.2s;
}

input:focus, select:focus, textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-dim);
}

input[type="date"] { font-family: var(--font-mono); font-size: 12px; }

.form-row { margin-bottom: 16px; }

.form-row label {
  display: block;
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-muted);
  margin-bottom: 6px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

/* --- Alerts --- */

.alert {
  padding: 14px 20px;
  border-radius: var(--radius);
  margin-bottom: 24px;
  font-size: 13px;
  border: 1px solid;
  display: flex;
  align-items: center;
  gap: 10px;
  animation: fadeUp 0.3s ease both;
}

.alert::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
  flex-shrink: 0;
  animation: glowPulse 2s ease infinite;
}

.alert-warning {
  background: var(--warning-dim);
  border-color: rgba(232, 168, 56, 0.2);
  color: var(--accent);
}

.alert-warning::before { background: var(--accent); }

.alert-error {
  background: var(--error-dim);
  border-color: rgba(239, 95, 95, 0.2);
  color: var(--error);
}

.alert-error::before { background: var(--error); }

/* --- SVG chart --- */

.chart-container {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 20px;
}

.chart-container svg { width: 100%; height: 150px; }

/* --- Confirm dialog --- */

.dialog-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  animation: fadeUp 0.15s ease both;
}

.dialog {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  max-width: 400px;
  width: 90%;
  box-shadow: 0 24px 64px rgba(0, 0, 0, 0.5);
}

.dialog h3 {
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--text-primary);
  text-transform: none;
  letter-spacing: -0.02em;
}

.dialog p { color: var(--text-secondary); margin-bottom: 24px; font-size: 14px; }
.dialog-actions { display: flex; gap: 8px; justify-content: flex-end; }

/* --- Empty state --- */

.empty-state {
  text-align: center;
  padding: 80px 20px;
  color: var(--text-muted);
}

.empty-state h2 {
  font-family: var(--font-display);
  color: var(--text-secondary);
  margin-bottom: 8px;
  font-weight: 600;
}

.empty-state p { font-size: 14px; }
.empty-state code {
  font-family: var(--font-mono);
  background: var(--accent-dim);
  color: var(--accent);
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 13px;
}

/* --- Misc --- */

.section { margin-bottom: 36px; }
.flex { display: flex; align-items: center; }
.gap-8 { gap: 8px; }
.gap-16 { gap: 16px; }
.mt-16 { margin-top: 16px; }
.mb-8 { margin-bottom: 8px; }
.text-mono { font-family: var(--font-mono); }
.text-sm { font-size: 13px; }
.text-muted { color: var(--text-muted); }
.text-secondary { color: var(--text-secondary); }

/* --- Scrollbar --- */

::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--border-hover); }

/* --- Student Switcher --- */

.student-switcher {
  display: flex;
  gap: 6px;
  padding: 12px 16px 8px;
  border-top: 1px solid var(--border);
  margin-top: 8px;
}

.student-switcher button {
  flex: 1;
  padding: 6px 8px;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text-secondary);
  font-family: var(--font-mono);
  font-size: 12px;
  cursor: pointer;
  transition: all 0.15s;
}

.student-switcher button:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.student-switcher button.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #000;
  font-weight: 600;
}

/* --- Tutor Chat --- */

.tutor-panel { transition: box-shadow 0.2s; }
.tutor-panel:focus-within { box-shadow: 0 0 0 2px var(--accent); }

#messages-yassin, #messages-youssef {
  scrollbar-width: thin;
}

.chat-bubble > div {
  word-break: break-word;
}

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}

.typing-cursor {
  display: inline-block;
  animation: blink 0.8s step-end infinite;
  color: var(--accent);
  font-weight: 700;
}

@keyframes blink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0; }
}

textarea:focus {
  border-color: var(--accent) !important;
  box-shadow: 0 0 0 2px rgba(99,102,241,0.2);
}

@media (max-width: 700px) {
  #tutor-root { flex-direction: column; height: auto !important; }
  .tutor-panel { min-height: 400px; }
}