:root {
  --color-primary: #5fcf80;
  --color-primary-dark: #3ea863;
  --color-heading: #273d4e;
  --color-body: #444444;
  --color-muted: #6b7280;
  --color-line: #e5e7eb;
  --color-soft: #f3fbf6;
  --color-warm: #f59e0b;
}

html {
  font-size: 16px;
  min-height: 100%;
  position: relative;
}

body {
  background: #ffffff;
  color: var(--color-body);
  font-family: Arial, Helvetica, sans-serif;
  margin-bottom: 72px;
}

a {
  color: var(--color-primary-dark);
  text-decoration: none;
}

a:hover {
  color: #247646;
}

.btn {
  border-radius: 50px;
  font-weight: 700;
  padding: 0.7rem 1.35rem;
}

.btn-primary {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #ffffff;
}

.btn-primary:hover,
.btn-primary:focus {
  background: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
  color: #ffffff;
}

.btn-outline-primary {
  border-color: var(--color-primary);
  color: var(--color-primary-dark);
}

.btn-outline-primary:hover,
.btn-outline-primary:focus {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #ffffff;
}

.btn:focus,
.btn:active:focus,
.btn-link.nav-link:focus,
.form-control:focus,
.form-check-input:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 0.16rem rgba(95, 207, 128, 0.25);
}

.site-header {
  background: #ffffff;
  border-bottom: 1px solid #edf2ef;
  box-shadow: 0 2px 18px rgba(39, 61, 78, 0.06);
  position: sticky;
  top: 0;
  z-index: 1020;
}

.navbar {
  min-height: 72px;
}

.navbar-brand {
  color: var(--color-heading);
  font-size: 1.65rem;
  letter-spacing: 0;
}

.navbar-nav {
  align-items: center;
  gap: 8px;
}

.navbar-nav .nav-link {
  color: var(--color-heading) !important;
  font-size: 0.95rem;
  font-weight: 700;
}

.navbar-nav .nav-link:hover {
  color: var(--color-primary-dark) !important;
}

.nav-cta {
  padding: 0.55rem 1.2rem;
}

.nav-logout {
  padding-left: 0;
  padding-right: 0;
}

.app-shell {
  padding-bottom: 36px;
}

.app-shell main > .page-heading,
.app-shell main > .detail-grid,
.app-shell main > .dashboard-grid,
.app-shell main > .stack-list,
.app-shell main > .alert,
.app-shell main > .empty-state {
  margin-left: auto;
  margin-right: auto;
  max-width: 1140px;
  padding-left: 12px;
  padding-right: 12px;
}

.catalog-hero {
  background: var(--color-soft);
  border-bottom: 1px solid #dff3e7;
  padding: 76px 0 58px;
}

.catalog-hero__inner {
  align-items: center;
  display: grid;
  gap: 42px;
  grid-template-columns: minmax(0, 1.2fr) minmax(280px, 0.8fr);
}

.catalog-hero__copy h1 {
  color: var(--color-heading);
  font-size: clamp(2.2rem, 4vw, 4.1rem);
  font-weight: 800;
  letter-spacing: 0;
  line-height: 1.08;
  margin: 0 0 18px;
  max-width: 820px;
}

.catalog-hero__copy .lead {
  max-width: 680px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.catalog-hero__panel {
  background: #ffffff;
  border: 1px solid #dbeee3;
  border-radius: 8px;
  box-shadow: 0 18px 42px rgba(39, 61, 78, 0.08);
  display: grid;
  gap: 14px;
  padding: 24px;
}

.catalog-hero__panel div {
  align-items: center;
  background: #fbfdfc;
  border: 1px solid #ecf5ef;
  border-radius: 8px;
  display: flex;
  justify-content: space-between;
  padding: 16px;
}

.hero-number {
  color: var(--color-primary-dark);
  font-size: 2rem;
  font-weight: 800;
}

.content-section {
  padding: 54px 0 20px;
}

.section-title {
  margin-bottom: 26px;
}

.section-title h2,
.page-heading h1,
.login-intro h1 {
  color: var(--color-heading);
  font-weight: 800;
  letter-spacing: 0;
}

.section-title h2 {
  font-size: 2rem;
  margin: 0;
}

.page-heading {
  align-items: flex-start;
  display: flex;
  gap: 24px;
  justify-content: space-between;
  margin-bottom: 24px;
  margin-top: 34px;
}

.page-heading h1 {
  font-size: 2rem;
  margin: 0;
}

.lead {
  color: #5f6f7a;
  font-size: 1.08rem;
}

.eyebrow {
  color: var(--color-primary-dark);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0;
  margin-bottom: 8px;
  text-transform: uppercase;
}

.course-grid {
  display: grid;
  gap: 24px;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.course-card,
.line-item,
.question-block,
.empty-state,
.login-card {
  background: #ffffff;
  border: 1px solid var(--color-line);
  border-radius: 8px;
  box-shadow: 0 10px 30px rgba(39, 61, 78, 0.07);
}

.course-card {
  display: flex;
  flex-direction: column;
  min-height: 340px;
  padding: 24px;
  transition: border-color 160ms ease, transform 160ms ease;
}

.course-card:hover {
  border-color: #b8e7c9;
  transform: translateY(-3px);
}

.course-card__header,
.course-actions,
.question-block__head,
.exam-meta {
  align-items: center;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: space-between;
}

.course-card h2,
.line-item h3,
.question-block h2 {
  color: var(--color-heading);
  letter-spacing: 0;
}

.course-card h2 {
  font-size: 1.25rem;
  margin: 18px 0 6px;
}

.provider,
.muted {
  color: var(--color-muted);
}

.course-price {
  color: var(--color-heading);
  font-weight: 800;
}

.strong {
  font-weight: 700;
  margin-bottom: 4px;
}

.status-pill {
  background: #eefaf2;
  border: 1px solid #c9efd6;
  border-radius: 999px;
  color: var(--color-primary-dark);
  display: inline-flex;
  font-size: 0.82rem;
  font-weight: 800;
  line-height: 1;
  padding: 8px 10px;
}

.status-pill--success {
  background: #ecfdf5;
  border-color: #a7f3d0;
  color: #047857;
}

.metrics {
  display: grid;
  gap: 10px;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin: auto 0 18px;
}

.metrics div {
  background: #fbfdfc;
  border: 1px solid #ecf5ef;
  border-radius: 8px;
  padding: 10px;
}

.metrics dt {
  color: var(--color-muted);
  font-size: 0.78rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.metrics dd {
  color: var(--color-heading);
  font-weight: 800;
  margin: 0;
}

.detail-grid,
.dashboard-grid {
  display: grid;
  gap: 24px;
  grid-template-columns: minmax(0, 1.35fr) minmax(280px, 0.65fr);
}

.dashboard-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.stack-list {
  display: grid;
  gap: 12px;
}

.line-item {
  align-items: flex-start;
  display: flex;
  gap: 14px;
  padding: 16px;
}

.line-item--compact {
  justify-content: space-between;
}

.line-item h3 {
  font-size: 1rem;
  margin: 0 0 4px;
}

.line-item p {
  color: #5f6f7a;
  margin: 0 0 6px;
}

.line-item__number,
.metric {
  align-items: center;
  background: #fff7ed;
  border: 1px solid #fed7aa;
  border-radius: 999px;
  color: #9a3412;
  display: inline-flex;
  flex: 0 0 auto;
  font-size: 0.8rem;
  font-weight: 800;
  justify-content: center;
  min-height: 34px;
  min-width: 34px;
  padding: 0 10px;
}

.metric {
  background: #f8fafc;
  border-color: var(--color-line);
  color: var(--color-heading);
  margin-left: 10px;
}

.action-stack {
  display: flex;
  justify-content: flex-end;
  min-width: 180px;
}

.exam-meta {
  background: #ffffff;
  border: 1px solid var(--color-line);
  border-radius: 8px;
  color: var(--color-heading);
  font-weight: 700;
  padding: 12px 14px;
}

.question-block {
  padding: 20px;
}

.question-block h2 {
  font-size: 1.05rem;
  margin: 14px 0;
}

.option-list {
  display: grid;
  gap: 8px;
  margin: 0;
  padding-left: 22px;
}

.option-list li {
  background: #fbfdfc;
  border: 1px solid #ecf5ef;
  border-radius: 8px;
  padding: 10px 12px;
}

.option-list .correct-option {
  background: #ecfdf5;
  border-color: #a7f3d0;
}

.explanation {
  background: #fffbeb;
  border: 1px solid #fde68a;
  border-radius: 8px;
  color: #713f12;
  margin: 14px 0 0;
  padding: 12px;
}

.empty-state {
  margin-top: 24px;
  padding: 24px;
}

.login-page {
  background: var(--color-soft);
  min-height: calc(100vh - 128px);
  padding: 72px 0;
}

.login-shell {
  align-items: center;
  display: grid;
  gap: 42px;
  grid-template-columns: minmax(0, 1fr) minmax(320px, 420px);
}

.login-intro {
  max-width: 640px;
}

.login-intro h1 {
  font-size: clamp(2.1rem, 3.4vw, 3.6rem);
  line-height: 1.08;
  margin-bottom: 18px;
}

.login-intro p {
  color: #5f6f7a;
  font-size: 1.08rem;
}

.login-highlights {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 28px;
}

.login-highlights span {
  background: #ffffff;
  border: 1px solid #dbeee3;
  border-radius: 999px;
  color: var(--color-heading);
  font-weight: 700;
  padding: 10px 14px;
}

.login-card {
  padding: 32px;
}

.login-card h2 {
  color: var(--color-heading);
  font-size: 1.6rem;
  font-weight: 800;
  letter-spacing: 0;
  margin-bottom: 6px;
}

.login-card .form-control {
  border-color: #dfe7e2;
  border-radius: 6px;
}

.login-links {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  justify-content: space-between;
  margin-top: 18px;
}

.solved-hero {
  background: var(--color-soft);
  border-bottom: 1px solid #dff3e7;
  padding: 54px 0 42px;
}

.solved-hero h1 {
  color: var(--color-heading);
  font-size: clamp(2rem, 3vw, 3.2rem);
  font-weight: 800;
  letter-spacing: 0;
}

.solved-year-grid {
  display: grid;
  gap: 22px;
  grid-template-columns: repeat(auto-fit, minmax(310px, 1fr));
}

.solved-year-card {
  background: #ffffff;
  border: 1px solid var(--color-line);
  border-radius: 8px;
  box-shadow: 0 10px 30px rgba(39, 61, 78, 0.07);
  padding: 22px;
}

.solved-year-card__head {
  align-items: flex-start;
  display: flex;
  gap: 12px;
  justify-content: space-between;
}

.solved-year-card h2 {
  color: var(--color-heading);
  font-size: 1.55rem;
  font-weight: 800;
  letter-spacing: 0;
  margin: 10px 0 8px;
}

.source-badge,
.question-type,
.answer-pill {
  background: #f8fafc;
  border: 1px solid var(--color-line);
  border-radius: 999px;
  color: var(--color-heading);
  display: inline-flex;
  font-size: 0.78rem;
  font-weight: 800;
  line-height: 1;
  padding: 8px 10px;
}

.part-card-grid {
  display: grid;
  gap: 12px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin-top: 18px;
}

.part-card {
  background: #fbfdfc;
  border: 1px solid #dbeee3;
  border-radius: 8px;
  color: var(--color-body);
  display: grid;
  gap: 6px;
  min-height: 130px;
  padding: 16px;
}

.part-card:hover {
  border-color: var(--color-primary);
  color: var(--color-body);
}

.part-card span {
  color: var(--color-primary-dark);
  font-weight: 800;
}

.part-card strong {
  color: var(--color-heading);
  font-size: 1.02rem;
}

.part-card small {
  color: var(--color-muted);
  font-weight: 700;
}

.solved-detail-layout {
  display: grid;
  gap: 24px;
  grid-template-columns: minmax(340px, 0.85fr) minmax(0, 1.15fr);
  margin: 0 auto 40px;
  max-width: 1320px;
  padding: 0 12px;
}

.solved-detail-layout--single {
  grid-template-columns: minmax(0, 1fr);
  max-width: 980px;
}

.source-link {
  color: var(--color-primary-dark);
  display: inline-flex;
  font-weight: 800;
  margin-top: 8px;
}

.paper-viewer {
  align-self: start;
  background: #ffffff;
  border: 1px solid var(--color-line);
  border-radius: 8px;
  box-shadow: 0 10px 30px rgba(39, 61, 78, 0.07);
  padding: 14px;
  position: sticky;
  top: 92px;
}

.paper-viewer__head {
  align-items: center;
  display: flex;
  justify-content: space-between;
  padding: 4px 2px 12px;
}

.paper-viewer iframe {
  border: 1px solid var(--color-line);
  border-radius: 8px;
  height: calc(100vh - 190px);
  min-height: 560px;
  width: 100%;
}

.solved-question-list {
  display: grid;
  gap: 16px;
}

.solved-question-card {
  background: #ffffff;
  border: 1px solid var(--color-line);
  border-radius: 8px;
  box-shadow: 0 10px 30px rgba(39, 61, 78, 0.07);
  padding: 18px;
}

.solved-question-card__head {
  align-items: center;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: space-between;
  margin-bottom: 14px;
}

.solved-question-card__head > div {
  align-items: center;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.answer-pill {
  background: #eefaf2;
  border-color: #c9efd6;
  color: var(--color-primary-dark);
  font-size: 0.9rem;
}

.solved-question-card pre {
  background: #fbfdfc;
  border: 1px solid #ecf5ef;
  border-radius: 8px;
  color: var(--color-body);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 0.95rem;
  line-height: 1.55;
  padding: 14px;
  white-space: pre-wrap;
}

.question-assets {
  display: grid;
  gap: 12px;
  margin-top: 12px;
}

.question-assets figure {
  background: #fbfdfc;
  border: 1px solid #ecf5ef;
  border-radius: 8px;
  margin: 0;
  overflow: hidden;
}

.question-assets img {
  display: block;
  height: auto;
  max-height: 720px;
  object-fit: contain;
  width: 100%;
}

.answer-box {
  background: #f8fafc;
  border: 1px solid var(--color-line);
  border-radius: 8px;
  margin-top: 12px;
  padding: 14px;
}

.answer-box strong {
  color: var(--color-heading);
}

.answer-box p {
  margin: 8px 0 0;
}

.answer-box small {
  color: var(--color-muted);
  display: block;
  font-weight: 700;
  margin-top: 10px;
}

.footer {
  background: #ffffff;
  line-height: 56px;
  min-height: 56px;
  position: absolute;
  bottom: 0;
  width: 100%;
}

@media (max-width: 768px) {
  .catalog-hero {
    padding: 46px 0 36px;
  }

  .catalog-hero__inner,
  .login-shell,
  .solved-detail-layout,
  .detail-grid,
  .dashboard-grid {
    grid-template-columns: 1fr;
  }

  .page-heading,
  .course-actions,
  .question-block__head {
    align-items: stretch;
    flex-direction: column;
  }

  .metrics {
    grid-template-columns: 1fr;
  }

  .action-stack {
    justify-content: flex-start;
    min-width: 0;
  }

  .line-item--compact {
    align-items: flex-start;
    flex-direction: column;
  }

  .metric {
    margin-left: 0;
  }

  .navbar-nav {
    align-items: flex-start;
    gap: 2px;
    padding: 12px 0;
  }

  .part-card-grid {
    grid-template-columns: 1fr;
  }

  .paper-viewer {
    position: static;
  }

  .paper-viewer iframe {
    height: 520px;
    min-height: 420px;
  }
}