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

:root {
  --nvidia-green: #76b900;
  --nvidia-dark-green: #5a8f00;
  --nvidia-light-green: #e8f5d0;
  --nvidia-xlight-green: #f4fbe8;
  --bg: #f8f9fa;
  --bg-card: #ffffff;
  --text-primary: #1a1a1a;
  --text-secondary: #555;
  --text-muted: #888;
  --border: #e2e8d4;
  --border-green: #c5e089;
  --shadow-sm: 0 1px 4px rgba(0,0,0,0.07);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.10);
  --shadow-green: 0 4px 16px rgba(118,185,0,0.15);
  --radius: 10px;
  --radius-lg: 16px;
}

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

body {
  font-family: 'Open Sans', Arial, sans-serif;
  background: var(--bg);
  color: var(--text-primary);
  font-size: 15px;
  line-height: 1.6;
}

/* ── Scrollbar ── */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: #f0f0f0; }
::-webkit-scrollbar-thumb { background: var(--nvidia-green); border-radius: 3px; }

/* ── Navbar ── */
.navbar {
  background: #fff;
  border-bottom: 2px solid var(--nvidia-green);
  box-shadow: var(--shadow-sm);
  padding: 0 24px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 1000;
}

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

.navbar-logo {
  width: 36px;
  height: 36px;
  background: var(--nvidia-green);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.navbar-logo svg { width: 22px; height: 22px; fill: #fff; }

.navbar-title {
  font-weight: 700;
  font-size: 15px;
  color: var(--text-primary);
  line-height: 1.2;
}

.navbar-subtitle {
  font-size: 11px;
  color: var(--text-muted);
  font-weight: 400;
}

.navbar-nav {
  display: flex;
  align-items: center;
  gap: 4px;
  list-style: none;
}

.navbar-nav a {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  border-radius: 8px;
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-secondary);
  transition: background 0.18s, color 0.18s;
}

.navbar-nav a:hover,
.navbar-nav a.active {
  background: var(--nvidia-light-green);
  color: var(--nvidia-dark-green);
}

.navbar-nav a i { font-size: 15px; }

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

.user-avatar {
  width: 36px;
  height: 36px;
  background: var(--nvidia-green);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 14px;
  overflow: hidden;
}

.user-avatar img { width: 100%; height: 100%; object-fit: cover; }

.navbar-hamburger {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
  font-size: 22px;
  color: var(--text-primary);
}

/* ── Sidebar mobile ── */
.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.4);
  z-index: 999;
}

.sidebar-drawer {
  display: none;
  position: fixed;
  top: 0; left: 0;
  width: 260px;
  height: 100%;
  background: #fff;
  z-index: 1100;
  padding: 24px 16px;
  box-shadow: 4px 0 24px rgba(0,0,0,0.12);
  flex-direction: column;
  gap: 4px;
}

.sidebar-drawer.open { display: flex; }
.sidebar-overlay.open { display: block; }

.sidebar-drawer a {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  border-radius: 8px;
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-secondary);
  transition: background 0.18s;
}

.sidebar-drawer a:hover,
.sidebar-drawer a.active {
  background: var(--nvidia-light-green);
  color: var(--nvidia-dark-green);
}

/* ── Main content ── */
.main-content {
  max-width: 1100px;
  margin: 0 auto;
  padding: 32px 20px 60px;
}

/* ── Page header ── */
.page-header {
  margin-bottom: 28px;
}

.page-header h1 {
  font-size: 26px;
  font-weight: 700;
  color: var(--text-primary);
}

.page-header p {
  color: var(--text-muted);
  margin-top: 4px;
  font-size: 14px;
}

/* ── Cards ── */
.card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border);
  overflow: hidden;
  transition: box-shadow 0.2s;
}

.card:hover { box-shadow: var(--shadow-md); }

.card-header {
  padding: 18px 22px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.card-header h2, .card-header h3 {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
}

.card-body { padding: 22px; }

/* ── Stats grid ── */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
  margin-bottom: 28px;
}

.stat-card {
  background: #fff;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  padding: 20px;
  display: flex;
  align-items: center;
  gap: 16px;
  box-shadow: var(--shadow-sm);
}

.stat-icon {
  width: 48px;
  height: 48px;
  background: var(--nvidia-light-green);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  color: var(--nvidia-green);
  flex-shrink: 0;
}

.stat-val { font-size: 26px; font-weight: 700; color: var(--text-primary); }
.stat-label { font-size: 12px; color: var(--text-muted); font-weight: 500; margin-top: 2px; }

/* ── Progress bar ── */
.progress-bar-outer {
  background: #e9ecef;
  border-radius: 99px;
  height: 10px;
  overflow: hidden;
}

.progress-bar-inner {
  background: linear-gradient(90deg, var(--nvidia-green), var(--nvidia-dark-green));
  height: 100%;
  border-radius: 99px;
  transition: width 0.6s ease;
}

/* ── Badges ── */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 3px 10px;
  border-radius: 99px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.3px;
}

.badge-green { background: var(--nvidia-light-green); color: var(--nvidia-dark-green); }
.badge-orange { background: #fff3e0; color: #e65100; }
.badge-red { background: #fde8e8; color: #c62828; }
.badge-gray { background: #f0f0f0; color: #666; }
.badge-blue { background: #e3f2fd; color: #1565c0; }

/* ── Buttons ── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 9px 20px;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  border: none;
  text-decoration: none;
  transition: all 0.18s;
  white-space: nowrap;
}

.btn-primary {
  background: var(--nvidia-green);
  color: #fff;
}
.btn-primary:hover { background: var(--nvidia-dark-green); color: #fff; }

.btn-outline {
  background: transparent;
  border: 1.5px solid var(--nvidia-green);
  color: var(--nvidia-green);
}
.btn-outline:hover { background: var(--nvidia-light-green); }

.btn-ghost {
  background: transparent;
  border: 1.5px solid var(--border);
  color: var(--text-secondary);
}
.btn-ghost:hover { background: var(--bg); }

.btn-danger {
  background: #e53935;
  color: #fff;
}
.btn-danger:hover { background: #b71c1c; }

.btn-sm { padding: 6px 14px; font-size: 13px; }
.btn-lg { padding: 12px 28px; font-size: 15px; }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

/* ── Assignment list cards ── */
.assignment-card {
  background: #fff;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  padding: 20px 22px;
  display: flex;
  align-items: flex-start;
  gap: 16px;
  transition: box-shadow 0.2s, border-color 0.2s;
}

.assignment-card:hover { box-shadow: var(--shadow-md); }

.assignment-card.locked {
  background: #fafafa;
  opacity: 0.7;
}

.assignment-card.passed { border-color: var(--nvidia-green); }

.assignment-num {
  width: 40px;
  height: 40px;
  background: var(--nvidia-light-green);
  color: var(--nvidia-green);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 15px;
  flex-shrink: 0;
}

.assignment-card.locked .assignment-num {
  background: #f0f0f0;
  color: #aaa;
}

.assignment-card.passed .assignment-num {
  background: var(--nvidia-green);
  color: #fff;
}

.assignment-info { flex: 1; min-width: 0; }
.assignment-info h3 { font-size: 15px; font-weight: 600; margin-bottom: 4px; }
.assignment-info p { font-size: 13px; color: var(--text-muted); }
.assignment-meta { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 8px; align-items: center; }

/* ── Forms ── */
.form-group { margin-bottom: 20px; }

.form-label {
  display: block;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 6px;
}

.form-control {
  width: 100%;
  padding: 10px 14px;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  font-size: 14px;
  font-family: inherit;
  color: var(--text-primary);
  background: #fff;
  transition: border-color 0.18s, box-shadow 0.18s;
  outline: none;
}

.form-control:focus {
  border-color: var(--nvidia-green);
  box-shadow: 0 0 0 3px rgba(118,185,0,0.12);
}

textarea.form-control { resize: vertical; min-height: 120px; }

.form-hint { font-size: 12px; color: var(--text-muted); margin-top: 4px; }

/* ── OTP input ── */
.otp-input-group {
  display: flex;
  gap: 10px;
  justify-content: center;
}

.otp-digit {
  width: 52px;
  height: 60px;
  text-align: center;
  font-size: 24px;
  font-weight: 700;
  border: 2px solid var(--border);
  border-radius: 10px;
  outline: none;
  transition: border-color 0.18s, box-shadow 0.18s;
  color: var(--text-primary);
  background: #fff;
}

.otp-digit:focus {
  border-color: var(--nvidia-green);
  box-shadow: 0 0 0 3px rgba(118,185,0,0.15);
}

/* ── Quiz ── */
.quiz-question {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 16px;
}

.quiz-question .q-text {
  font-weight: 600;
  font-size: 14px;
  margin-bottom: 14px;
  color: var(--text-primary);
}

.option-label {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  margin-bottom: 8px;
  cursor: pointer;
  font-size: 14px;
  transition: background 0.15s, border-color 0.15s;
}

.option-label:hover { background: var(--nvidia-xlight-green); border-color: var(--border-green); }

.option-label input[type="radio"] { accent-color: var(--nvidia-green); width: 16px; height: 16px; flex-shrink: 0; }

.option-label:has(input:checked) {
  background: var(--nvidia-light-green);
  border-color: var(--nvidia-green);
}

/* ── Alerts / messages ── */
.alert {
  padding: 12px 16px;
  border-radius: 8px;
  font-size: 14px;
  display: flex;
  align-items: flex-start;
  gap: 10px;
  margin-bottom: 16px;
}

.alert-success { background: #e8f5d0; border: 1px solid #c5e089; color: #3a6200; }
.alert-error { background: #fde8e8; border: 1px solid #f5c2c2; color: #7b0000; }
.alert-warning { background: #fff8e1; border: 1px solid #ffe082; color: #6d4c00; }
.alert-info { background: #e3f2fd; border: 1px solid #90caf9; color: #0d47a1; }

/* ── File upload ── */
.file-upload-area {
  border: 2px dashed var(--border-green);
  border-radius: var(--radius);
  padding: 32px;
  text-align: center;
  cursor: pointer;
  transition: background 0.18s, border-color 0.18s;
  background: var(--nvidia-xlight-green);
}

.file-upload-area:hover { background: var(--nvidia-light-green); border-color: var(--nvidia-green); }
.file-upload-area i { font-size: 36px; color: var(--nvidia-green); margin-bottom: 10px; display: block; }
.file-upload-area p { font-size: 14px; color: var(--text-muted); }
.file-upload-area input[type="file"] { display: none; }

/* ── Resource cards ── */
.resource-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 18px;
  display: flex;
  align-items: center;
  gap: 14px;
  text-decoration: none;
  color: var(--text-primary);
  transition: box-shadow 0.18s, border-color 0.18s;
}

.resource-card:hover {
  box-shadow: var(--shadow-green);
  border-color: var(--border-green);
  color: var(--text-primary);
}

.resource-icon {
  width: 42px;
  height: 42px;
  background: var(--nvidia-light-green);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  color: var(--nvidia-green);
  flex-shrink: 0;
}

/* ── Auth pages ── */
.auth-wrapper {
  min-height: 100vh;
  background: linear-gradient(135deg, #f4fbe8 0%, #e8f5d0 50%, #d4edaa 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.auth-card {
  background: #fff;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  padding: 40px;
  width: 100%;
  max-width: 440px;
}

.auth-logo {
  text-align: center;
  margin-bottom: 28px;
}

.auth-logo-icon {
  width: 64px;
  height: 64px;
  background: var(--nvidia-green);
  border-radius: 16px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 14px;
}

.auth-logo-icon svg { width: 36px; height: 36px; fill: #fff; }
.auth-logo h1 { font-size: 20px; font-weight: 700; margin-bottom: 4px; }
.auth-logo p { font-size: 13px; color: var(--text-muted); }

/* ── Submission result ── */
.result-block {
  background: var(--nvidia-xlight-green);
  border: 1px solid var(--border-green);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 20px;
}

.result-block.failed {
  background: #fde8e8;
  border-color: #f5c2c2;
}

/* ── Divider ── */
.divider {
  border: none;
  border-top: 1px solid var(--border);
  margin: 20px 0;
}

/* ── Table ── */
.table-wrapper { overflow-x: auto; border-radius: var(--radius); }

table.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}

table.data-table th {
  background: var(--nvidia-xlight-green);
  color: var(--text-secondary);
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  padding: 10px 14px;
  text-align: left;
  border-bottom: 1px solid var(--border);
}

table.data-table td {
  padding: 12px 14px;
  border-bottom: 1px solid var(--border);
  color: var(--text-primary);
}

table.data-table tr:last-child td { border-bottom: none; }
table.data-table tr:hover td { background: var(--nvidia-xlight-green); }

/* ── Empty state ── */
.empty-state {
  text-align: center;
  padding: 48px 20px;
  color: var(--text-muted);
}

.empty-state i { font-size: 48px; margin-bottom: 14px; color: var(--border-green); display: block; }
.empty-state p { font-size: 15px; }

/* ── Responsive ── */
@media (max-width: 768px) {
  .navbar-nav { display: none; }
  .navbar-hamburger { display: block; }

  .main-content { padding: 20px 14px 48px; }

  .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }

  .assignment-card { flex-direction: column; gap: 12px; }

  .auth-card { padding: 28px 20px; }

  .otp-digit { width: 42px; height: 52px; font-size: 20px; }

  .page-header h1 { font-size: 21px; }
}

@media (max-width: 480px) {
  .stats-grid { grid-template-columns: 1fr 1fr; }
  .otp-input-group { gap: 7px; }
  .otp-digit { width: 36px; height: 46px; font-size: 18px; }
}

/* Markdown rendered content */
.markdown-body h1,.markdown-body h2,.markdown-body h3 { font-weight:700; margin:16px 0 8px; color:var(--text-primary); }
.markdown-body h3 { font-size:15px; color:var(--nvidia-dark-green); }
.markdown-body p { margin:0 0 10px; }
.markdown-body ol,.markdown-body ul { padding-left:20px; margin:0 0 12px; }
.markdown-body li { margin-bottom:6px; line-height:1.6; }
.markdown-body strong { color:var(--text-primary); }
.markdown-body a { color:var(--nvidia-green); }
.markdown-body blockquote { border-left:3px solid var(--nvidia-green); margin:12px 0; padding:10px 14px; background:var(--nvidia-xlight-green); border-radius:0 6px 6px 0; color:var(--text-secondary); font-size:13px; }
.markdown-body blockquote p { margin:0; }
.markdown-body code { background:var(--bg);border:1px solid var(--border);border-radius:4px;padding:1px 5px;font-size:12px; }

/* Markdown tables */
.markdown-body table { width:100%; border-collapse:collapse; margin:12px 0; font-size:13px; }
.markdown-body th { background:var(--nvidia-xlight-green); color:var(--nvidia-dark-green); font-weight:700; padding:10px 12px; text-align:left; border:1px solid var(--border-green); }
.markdown-body td { padding:9px 12px; border:1px solid var(--border); color:var(--text-secondary); vertical-align:top; }
.markdown-body tr:nth-child(even) td { background:var(--bg); }