@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800;900&family=Fira+Code:wght@400;500&display=swap');

:root {
  --bg: #080d0d;
  --surface: #0c1515;
  --surface2: #101c1c;
  --border: #162424;
  --border-light: #1f3434;
  --accent: #0fb8b2;
  --accent2: #5eead4;
  --accent-glow: rgba(15,184,178,0.2);
  --green: #34d399;
  --red: #f87171;
  --yellow: #fbbf24;
  --text: #e2f0ef;
  --text-muted: #5a8585;
  --radius: 12px;
  --radius-sm: 8px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
[hidden] { display: none !important; }

body {
  font-family: 'Inter', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.6;
  background-image: radial-gradient(ellipse at 20% 20%, rgba(15,184,178,0.06) 0%, transparent 60%),
                    radial-gradient(ellipse at 80% 80%, rgba(94,234,212,0.04) 0%, transparent 60%);
}

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to   { opacity: 1; transform: translateY(0); }
}
.container { animation: fadeUp 0.4s ease; }

.container { max-width: 980px; margin: 0 auto; padding: 2rem 1.5rem; }

header {
  background: rgba(12,21,21,0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: 1rem 1.75rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  position: sticky;
  top: 0;
  z-index: 100;
}
header a { text-decoration: none; color: var(--text); font-weight: 800; font-size: 1.15rem; letter-spacing: -0.02em; }
header span { color: var(--accent); }

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  margin-bottom: 1.25rem;
  transition: border-color 0.2s;
}
.card:hover { border-color: var(--border-light); }
.card h2 { font-size: 0.78rem; font-weight: 700; margin-bottom: 1rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.06em; }

.hero { text-align: center; padding: 5rem 2rem 3rem; }
.hero h1 { font-size: 3rem; font-weight: 900; margin-bottom: 1rem; letter-spacing: -0.04em; line-height: 1.1; }
.hero h1 span {
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent2) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero p { color: var(--text-muted); font-size: 1.1rem; margin-bottom: 3rem; max-width: 480px; margin-left: auto; margin-right: auto; }

.action-cards { display: grid; grid-template-columns: 1fr 1fr; gap: 1.25rem; margin-top: 2rem; }
.action-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem 1.75rem;
  text-align: center;
  cursor: pointer;
  transition: border-color 0.2s, transform 0.2s, box-shadow 0.2s;
  text-decoration: none;
  color: var(--text);
  display: block;
  position: relative;
  overflow: hidden;
}
.action-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--accent-glow), transparent);
  opacity: 0;
  transition: opacity 0.3s;
}
.action-card:hover { border-color: var(--accent); transform: translateY(-3px); box-shadow: 0 8px 32px var(--accent-glow); }
.action-card:hover::before { opacity: 1; }
.action-card .icon { font-size: 2.25rem; margin-bottom: 0.9rem; display: block; }
.action-card h3 { font-size: 1.05rem; font-weight: 700; margin-bottom: 0.4rem; }
.action-card p { color: var(--text-muted); font-size: 0.875rem; line-height: 1.5; }

.form-group { margin-bottom: 1.25rem; }
label { display: block; font-size: 0.78rem; color: var(--text-muted); margin-bottom: 0.5rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.05em; }
input, select, textarea {
  width: 100%;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  padding: 0.7rem 1rem;
  font-size: 0.95rem;
  font-family: 'Inter', sans-serif;
  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-glow);
}
select option { background: var(--surface); }
textarea { resize: vertical; min-height: 120px; }
.num-row { display: grid; grid-template-columns: 1fr 1fr; gap: 1.25rem 2rem; }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.7rem 1.6rem;
  border-radius: var(--radius-sm);
  border: none;
  font-size: 0.9rem;
  font-weight: 600;
  font-family: 'Inter', sans-serif;
  cursor: pointer;
  transition: all 0.2s;
  text-decoration: none;
  letter-spacing: -0.01em;
}
.btn:active { transform: scale(0.97); }
.btn-primary {
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent2) 100%);
  color: #080d0d;
  box-shadow: 0 4px 16px var(--accent-glow);
  font-weight: 700;
}
.btn-primary:hover { box-shadow: 0 6px 24px var(--accent-glow); filter: brightness(1.1); }
.btn-outline { background: transparent; border: 1px solid var(--border-light); color: var(--text-muted); }
.btn-outline:hover { border-color: var(--accent); color: var(--accent); background: var(--accent-glow); }
.btn-full { width: 100%; }

.question-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 1.25rem;
  transition: border-color 0.2s;
}
.question-card:focus-within { border-color: var(--border-light); }
.question-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 0.9rem; }
.question-num { font-size: 0.73rem; color: var(--text-muted); font-weight: 700; text-transform: uppercase; letter-spacing: 0.08em; }
.points-badge {
  font-size: 0.75rem;
  background: rgba(15,184,178,0.1);
  color: var(--accent2);
  padding: 0.2rem 0.65rem;
  border-radius: 20px;
  font-weight: 600;
  border: 1px solid rgba(15,184,178,0.2);
}
.question-text { font-size: 1rem; line-height: 1.65; margin-bottom: 1rem; user-select: none; -webkit-user-select: none; }
.question-num, .points-badge, .options, .fill-blank-text { user-select: none; -webkit-user-select: none; }

.hint-box {
  background: rgba(15,184,178,0.06);
  border-left: 3px solid var(--accent);
  padding: 0.6rem 0.9rem;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

.options { display: flex; flex-direction: column; gap: 0.5rem; }
.option-label {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  padding: 0.7rem 1rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  cursor: pointer;
  transition: all 0.15s;
  font-size: 0.925rem;
}
.option-label:hover { border-color: var(--accent); background: rgba(15,184,178,0.06); }
.option-label input[type=radio] { accent-color: var(--accent); width: 16px; height: 16px; flex-shrink: 0; }
.option-label.selected { border-color: var(--accent); background: rgba(15,184,178,0.09); }

.fill-blank-text { font-size: 1rem; margin-bottom: 0.75rem; line-height: 1.8; }
.blank-input { display: inline-block; width: auto; min-width: 160px; padding: 0.3rem 0.75rem; }
.calc-area { min-height: 130px; font-family: 'Inter', sans-serif; }

.score-banner {
  background: linear-gradient(135deg, var(--surface) 0%, var(--surface2) 100%);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2.5rem 2rem;
  text-align: center;
  margin-bottom: 1.5rem;
  position: relative;
  overflow: hidden;
}
.score-banner::before {
  content: '';
  position: absolute;
  top: -50%;
  left: 50%;
  transform: translateX(-50%);
  width: 300px;
  height: 300px;
  background: radial-gradient(circle, var(--accent-glow) 0%, transparent 70%);
  pointer-events: none;
}
.grade-letter { font-size: 5rem; font-weight: 900; line-height: 1; margin-bottom: 0.5rem; letter-spacing: -0.05em; }
.grade-A { background: linear-gradient(135deg, #34d399, #059669); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.grade-B { background: linear-gradient(135deg, #60d394, #10b981); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.grade-C { background: linear-gradient(135deg, #fbbf24, #f59e0b); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.grade-D { background: linear-gradient(135deg, #fb923c, #ea580c); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.grade-F { background: linear-gradient(135deg, #f87171, #dc2626); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.score-text { font-size: 1.5rem; font-weight: 800; margin-bottom: 0.25rem; letter-spacing: -0.02em; }
.score-sub { color: var(--text-muted); font-size: 0.9rem; }

.progress-bar { height: 6px; background: var(--border); border-radius: 3px; overflow: hidden; margin: 1.25rem 0 0.5rem; }
.progress-fill {
  height: 100%;
  border-radius: 3px;
  background: linear-gradient(90deg, var(--accent), var(--accent2));
  transition: width 1.2s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: 0 0 8px var(--accent-glow);
}

.overall-feedback {
  background: rgba(15,184,178,0.06);
  border-left: 3px solid var(--accent);
  padding: 1.1rem 1.25rem;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin-bottom: 1.5rem;
  font-size: 0.95rem;
  line-height: 1.65;
}

.result-card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.5rem; margin-bottom: 1rem; }
.result-card.correct { border-left: 3px solid var(--green); }
.result-card.incorrect { border-left: 3px solid var(--red); }
.result-card.partial { border-left: 3px solid var(--yellow); }

.result-header { display: flex; justify-content: space-between; align-items: flex-start; margin-bottom: 0.75rem; }
.result-score { font-weight: 700; font-size: 0.95rem; white-space: nowrap; margin-left: 1rem; }
.result-score.full { color: var(--green); }
.result-score.partial { color: var(--yellow); }
.result-score.zero { color: var(--red); }

.answer-row { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin: 0.75rem 0; }
.answer-box { background: var(--bg); border-radius: var(--radius-sm); padding: 0.85rem 1rem; font-size: 0.875rem; border: 1px solid var(--border); }
.answer-box .label { font-size: 0.7rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.08em; margin-bottom: 0.4rem; font-weight: 700; }
.answer-box pre { white-space: pre-wrap; font-size: 0.85rem; line-height: 1.6; }

.feedback-box { background: var(--bg); border-radius: var(--radius-sm); padding: 0.85rem 1rem; font-size: 0.875rem; color: var(--text-muted); margin-top: 0.5rem; border: 1px solid var(--border); line-height: 1.6; }
.feedback-box .label { font-size: 0.7rem; color: var(--accent); text-transform: uppercase; letter-spacing: 0.08em; margin-bottom: 0.4rem; font-weight: 700; }

.spinner-page { display: flex; flex-direction: column; align-items: center; justify-content: center; min-height: 60vh; gap: 1.25rem; }
.spinner { width: 52px; height: 52px; border: 3px solid var(--border); border-top-color: var(--accent); border-right-color: var(--accent2); border-radius: 50%; animation: spin 0.7s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }

.alert { padding: 0.8rem 1.1rem; border-radius: var(--radius-sm); margin-bottom: 1rem; font-size: 0.875rem; font-weight: 500; }
.alert-error { background: rgba(248,113,113,0.08); border: 1px solid rgba(248,113,113,0.25); color: #fca5a5; }

.exam-meta { display: flex; gap: 0.75rem; flex-wrap: wrap; margin-bottom: 1.5rem; }
.meta-pill { background: rgba(15,184,178,0.08); border: 1px solid rgba(15,184,178,0.2); border-radius: 20px; padding: 0.3rem 0.9rem; font-size: 0.78rem; color: var(--accent2); font-weight: 500; }

.name-step { max-width: 440px; margin: 4rem auto; text-align: center; }
.name-step h2 { font-size: 1.6rem; font-weight: 800; margin-bottom: 0.5rem; letter-spacing: -0.02em; }
.name-step p { color: var(--text-muted); margin-bottom: 1.75rem; }

table { width: 100%; border-collapse: collapse; }
th { text-align: left; font-size: 0.72rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.08em; padding: 0.75rem 1.25rem; border-bottom: 1px solid var(--border); font-weight: 700; }
td { padding: 1rem 1.25rem; border-bottom: 1px solid var(--border); font-size: 0.875rem; vertical-align: middle; }
tr:last-child td { border-bottom: none; }
tr:hover td { background: rgba(15,184,178,0.03); }

.grade-pill { display: inline-block; font-weight: 700; font-size: 0.8rem; padding: 0.2rem 0.65rem; border-radius: 20px; }
.grade-pill.A { background: rgba(52,211,153,0.12); color: #34d399; }
.grade-pill.B { background: rgba(96,211,148,0.12); color: #60d394; }
.grade-pill.C { background: rgba(251,191,36,0.12); color: #fbbf24; }
.grade-pill.D { background: rgba(251,146,60,0.12); color: #fb923c; }
.grade-pill.F { background: rgba(248,113,113,0.12); color: #f87171; }

.status-pill { display: inline-block; font-size: 0.75rem; padding: 0.2rem 0.65rem; border-radius: 20px; font-weight: 600; }
.status-pill.graded { background: rgba(52,211,153,0.1); color: #34d399; }
.status-pill.grading { background: rgba(15,184,178,0.1); color: var(--accent); }
.status-pill.pending { background: rgba(90,133,133,0.1); color: var(--text-muted); }
.status-pill.error { background: rgba(248,113,113,0.1); color: #f87171; }

.stat-card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.5rem; text-align: center; }
.stat-card .num { font-size: 2.2rem; font-weight: 900; letter-spacing: -0.04em; background: linear-gradient(135deg, var(--accent), var(--accent2)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.stat-card .label { font-size: 0.75rem; color: var(--text-muted); margin-top: 0.25rem; font-weight: 600; text-transform: uppercase; letter-spacing: 0.06em; }

.exam-id-box { background: var(--surface2); border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 0.75rem 1rem; display: flex; align-items: center; gap: 1rem; margin-bottom: 1.5rem; }
.exam-id-box input { flex: 1; background: transparent; border: none; color: var(--text-muted); font-size: 0.85rem; box-shadow: none; }
.empty { text-align: center; padding: 3rem; color: var(--text-muted); font-size: 0.9rem; }

.stats-row { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1rem; margin-bottom: 1.5rem; }
.dashboard-header { margin-bottom: 1.5rem; }
.dashboard-header h1 { font-size: 1.6rem; font-weight: 800; letter-spacing: -0.02em; }
.dashboard-header p { color: var(--text-muted); margin-top: 0.25rem; }

@page { margin: 1.5cm; }
@media print {
  body { background: #fff; color: #000; }
  header, #spinner-page, #error-page { display: none !important; }
  #results-page { display: block !important; }
  /* Exam paper print: hide UI, show only questions */
  #share-banner { display: none !important; }
  #name-step { display: none !important; }
  #submit-exam-btn { display: none !important; }
  #submit-error { display: none !important; }
  #exam-body { display: block !important; }
  .btn { display: none !important; }
  input[type=text], input[type=radio], textarea { border: 1px solid #ccc !important; background: #fff !important; color: #000 !important; }
  .question-card, .card { background: #fff !important; border: 1px solid #ccc !important; break-inside: avoid; color: #000 !important; }
  .question-text, .fill-blank-text { color: #000 !important; user-select: text !important; -webkit-user-select: text !important; }
  .options label { color: #000 !important; }
  .meta-pill { background: #eee !important; color: #333 !important; }
  .score-banner { border: 2px solid #000; background: #f9f9f9; }
  .grade-letter { -webkit-text-fill-color: #000 !important; }
  .overall-feedback { border-left: 3px solid #000; background: #f5f5f5; color: #000; }
  .result-card { border: 1px solid #ccc; background: #fff; break-inside: avoid; }
  .answer-box, .feedback-box { background: #f5f5f5; color: #000; border-color: #ddd; }
  .progress-bar { display: none; }
}

@media (max-width: 600px) {
  .action-cards { grid-template-columns: 1fr; }
  .num-row { grid-template-columns: 1fr 1fr; }
  .answer-row { grid-template-columns: 1fr; }
  .hero h1 { font-size: 2rem; }
  .stats-row { grid-template-columns: 1fr 1fr; }
}