@import url("https://fonts.googleapis.com/css2?family=Manrope:wght@500;600;700;800&family=Plus+Jakarta+Sans:wght@500;600;700&display=swap");

body {
  margin: 0;
  font-family: "Manrope", "Plus Jakarta Sans", "Segoe UI", sans-serif;
  background:
    radial-gradient(circle at 90% 0, rgba(11, 95, 143, 0.12), transparent 28%),
    radial-gradient(circle at 10% 100%, rgba(239, 127, 45, 0.12), transparent 24%),
    linear-gradient(180deg, #eef5fb, #f9efe3);
  color: #223244;
  text-rendering: optimizeLegibility;
}

a {
  color: #0e5a8a;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.shell {
  width: min(1120px, 94vw);
  margin: 0 auto;
  padding: 24px 0 40px;
}

.hero {
  background: linear-gradient(135deg, #083451, #0e5a8a 48%, #63aef0);
  color: #fff;
  border-radius: 24px;
  padding: 28px;
  box-shadow: 0 18px 42px rgba(14, 90, 138, 0.2);
}

.hero p {
  line-height: 1.65;
  max-width: 70ch;
}

.brand-row {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
  color: #fff;
  font-weight: 800;
  letter-spacing: 0.02em;
}

.brand-row img {
  width: 38px;
  height: 38px;
  border-radius: 12px;
  object-fit: cover;
  box-shadow: 0 10px 22px rgba(0, 0, 0, 0.2);
}

.crumbs {
  margin: 0 0 14px;
  color: rgba(255, 255, 255, 0.88);
  font-size: 0.95rem;
}

.panel {
  margin-top: 18px;
  background: rgba(255, 255, 255, 0.9);
  border: 1px solid rgba(157, 183, 209, 0.45);
  border-radius: 22px;
  padding: 24px;
  box-shadow: 0 12px 28px rgba(35, 49, 66, 0.08);
}

.grid {
  display: grid;
  gap: 14px;
}

.grid.stats {
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
}

.stat {
  background: linear-gradient(180deg, #f7fbff, #edf4fb);
  border: 1px solid #d9e8f6;
  border-radius: 18px;
  padding: 16px;
}

.stat span {
  display: block;
  color: #667085;
  font-size: 0.82rem;
  margin-bottom: 6px;
}

.stat strong {
  font-size: 1.3rem;
}

.paper-list,
.topic-list {
  display: grid;
  gap: 12px;
}

.paper-card,
.link-card {
  border: 1px solid #d9e8f6;
  border-radius: 18px;
  background: linear-gradient(180deg, #ffffff, #f5f9fd);
  padding: 16px;
  transition:
    transform 0.18s ease,
    box-shadow 0.18s ease,
    border-color 0.18s ease;
}

.paper-card:hover,
.link-card:hover {
  transform: translateY(-2px);
  border-color: #aac9e6;
  box-shadow: 0 10px 20px rgba(14, 90, 138, 0.08);
}

.paper-card h3,
.link-card h3 {
  margin: 0 0 8px;
}

.meta {
  color: #5f7183;
  font-size: 0.95rem;
  line-height: 1.55;
}

.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}

.chips.compact {
  margin-top: 0;
}

.chip {
  display: inline-flex;
  align-items: center;
  padding: 6px 10px;
  border-radius: 999px;
  background: #e8f2fc;
  color: #0e5a8a;
  font-size: 0.85rem;
  font-weight: 700;
}

.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 18px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 17px;
  border-radius: 13px;
  font-weight: 700;
  border: 1px solid transparent;
  transition:
    transform 0.18s ease,
    box-shadow 0.18s ease,
    filter 0.18s ease;
}

.btn:hover {
  transform: translateY(-2px);
  filter: saturate(1.03);
}

.btn.primary {
  background: #0e5a8a;
  color: #fff;
  box-shadow: 0 10px 20px rgba(14, 90, 138, 0.24);
}

.btn.ghost {
  border: 1px solid #bfd4e9;
  background: #fff;
  color: #0e5a8a;
}

a:focus-visible,
button:focus-visible,
.btn:focus-visible {
  outline: 3px solid rgba(11, 95, 143, 0.38);
  outline-offset: 2px;
}

ul {
  line-height: 1.7;
}

.question-list {
  display: grid;
  gap: 14px;
}

.question-card {
  border: 1px solid #d9e8f6;
  border-radius: 18px;
  background: linear-gradient(180deg, #ffffff, #f7fbff);
  padding: 18px;
}

.question-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 10px;
}

.question-head h3 {
  margin: 0;
  font-size: 1.05rem;
}

.question-text {
  margin: 0 0 12px;
  line-height: 1.7;
}

.option-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 8px;
}

.option-item {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 10px;
  align-items: start;
  border: 1px solid #d9e8f6;
  border-radius: 14px;
  background: #fbfdff;
  padding: 10px 12px;
}

.option-item.correct {
  border-color: #b7dfc0;
  background: #eefbf1;
}

.option-key {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 26px;
  height: 26px;
  border-radius: 999px;
  background: #e8f2fc;
  color: #0e5a8a;
  font-weight: 800;
  font-size: 0.82rem;
}

.answer-line {
  margin: 12px 0 0;
  color: #0b4f78;
  font-weight: 700;
}

.explanation-box {
  margin-top: 12px;
  border-left: 4px solid #63aef0;
  background: #f4faff;
  padding: 12px 14px;
  border-radius: 0 14px 14px 0;
}

.explanation-box strong {
  display: block;
  margin-bottom: 6px;
}

.explanation-box p {
  margin: 0;
  color: #3b5166;
  line-height: 1.7;
}

footer {
  margin-top: 22px;
  color: #627487;
  font-size: 0.95rem;
}

@media (max-width: 720px) {
  .question-head {
    flex-direction: column;
  }

  .question-card {
    padding: 14px;
  }

  .option-item {
    grid-template-columns: 28px minmax(0, 1fr);
    padding: 9px 10px;
  }

  .option-key {
    width: 24px;
    height: 24px;
    font-size: 0.78rem;
  }
}