:root {
  --brand: #1b3a6b;
  --brand-dark: #122554;
  --brand-soft: #eef3fb;
  --uadeo: #c1272d;
  --uadeo-soft: #fef2f2;
  --lime: #a6ce39;
  --text: #172033;
  --muted: #64748b;
  --line: #e2e8f0;
  --surface: #ffffff;
  --soft: #f8fafc;
  --success: #047857;
  --warning-bg: #fffbeb;
  --warning-line: #fde68a;
  --warning-text: #92400e;
  --shadow: 0 14px 28px -12px rgba(27, 58, 107, 0.18);
  --radius: 18px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--text);
  background: #fff;
  font-family: Arial, Helvetica, sans-serif;
  line-height: 1.55;
}

button,
input,
textarea,
select {
  font: inherit;
}

a {
  color: inherit;
}

a:focus-visible,
button:focus-visible {
  outline: 3px solid #2563eb;
  outline-offset: 3px;
}

.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 200;
  padding: 10px 14px;
  color: #fff;
  background: var(--brand);
  border-radius: 8px;
  transform: translateY(-150%);
  transition: transform 0.2s ease;
}

.skip-link:focus {
  transform: translateY(0);
}

.container {
  width: min(1120px, calc(100% - 32px));
  margin-inline: auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.97);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(10px);
}

.navbar {
  display: flex;
  min-height: 66px;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 38px;
  height: 38px;
  place-items: center;
  color: #fff;
  background: var(--brand);
  border-radius: 10px;
  font-size: 19px;
}

.brand strong,
.brand small {
  display: block;
}

.brand strong {
  font-size: 14px;
}

.brand small {
  color: var(--muted);
  font-size: 11px;
}

.desktop-nav {
  display: flex;
  align-items: center;
  gap: 28px;
}

.desktop-nav a {
  position: relative;
  color: #475569;
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
}

.desktop-nav a::after {
  position: absolute;
  bottom: -7px;
  left: 0;
  width: 0;
  height: 2px;
  content: "";
  background: var(--brand);
  transition: width 0.2s ease;
}

.desktop-nav a:hover::after,
.desktop-nav a.active::after {
  width: 100%;
}

.desktop-nav a.active {
  color: var(--brand);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.menu-button {
  display: none;
  padding: 8px 10px;
  color: var(--text);
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
  cursor: pointer;
}

.mobile-menu {
  display: none;
  padding: 8px 0 16px;
  border-top: 1px solid var(--line);
}

.mobile-menu.open {
  display: block;
}

.mobile-menu a {
  display: block;
  padding: 11px 12px;
  margin-top: 4px;
  color: #334155;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
}

.mobile-menu a.active {
  color: var(--brand);
  background: var(--brand-soft);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  min-height: 40px;
  padding: 10px 15px;
  border: 1px solid transparent;
  border-radius: 10px;
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
  cursor: pointer;
  transition: opacity 0.2s ease, transform 0.2s ease, background 0.2s ease;
}

.btn:hover {
  opacity: 0.9;
}

.btn-brand {
  color: #fff;
  background: var(--brand);
}

.btn-red {
  color: #fff;
  background: var(--uadeo);
}

.btn-outline {
  color: var(--brand);
  background: #fff;
  border-color: var(--brand);
}

.btn-small {
  min-height: 34px;
  padding: 7px 11px;
  font-size: 12px;
}

.hero,
.page-hero {
  background: linear-gradient(145deg, #f8faff 0%, #eef3fb 55%, #fff7f7 100%);
}

.hero {
  padding: 82px 0;
}

.page-hero {
  padding: 48px 0;
  border-bottom: 1px solid var(--line);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.4fr 0.7fr;
  gap: 62px;
  align-items: center;
}

.badge,
.tag,
.status,
.filter-button {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  width: fit-content;
  padding: 5px 9px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 700;
}

.badge {
  color: var(--uadeo);
  background: #fff;
  border: 1px solid #fbd5d5;
}

.status {
  color: var(--success);
  background: #ecfdf5;
  border: 1px solid #a7f3d0;
}

.tag-blue {
  color: var(--brand);
  background: var(--brand-soft);
}

.tag-red {
  color: var(--uadeo);
  background: var(--uadeo-soft);
}

.tag-gray {
  color: #475569;
  background: #f1f5f9;
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--uadeo);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 16px;
  font-size: clamp(34px, 5vw, 54px);
  line-height: 1.08;
  letter-spacing: -0.04em;
}

h2 {
  margin-bottom: 8px;
  font-size: clamp(25px, 3vw, 32px);
  line-height: 1.15;
  letter-spacing: -0.025em;
}

h3 {
  margin-bottom: 8px;
  font-size: 17px;
  line-height: 1.3;
}

.hero h1 span,
.brand-color {
  color: var(--brand);
}

.lead {
  max-width: 670px;
  color: var(--muted);
  font-size: 16px;
}

.hero-actions,
.inline-actions,
.filter-row,
.profile-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
}

.hero-actions {
  margin-top: 26px;
}

.orcid {
  display: inline-flex;
  gap: 8px;
  align-items: center;
  margin-top: 22px;
  padding: 7px 10px;
  color: #475569;
  border: 1px solid var(--line);
  border-radius: 999px;
  font-size: 12px;
  font-weight: 700;
  text-decoration: none;
}

.orcid-dot {
  display: grid;
  width: 18px;
  height: 18px;
  place-items: center;
  color: #fff;
  background: var(--lime);
  border-radius: 50%;
  font-size: 10px;
}

.metrics {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 13px;
}

.metric,
.card,
.publication,
.notice {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.metric {
  padding: 21px 15px;
  text-align: center;
}

.metric strong {
  display: block;
  color: var(--brand);
  font-size: 29px;
}

.metric:nth-child(even) strong {
  color: var(--uadeo);
}

.metric span {
  display: block;
  margin-top: 3px;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.3;
}

.section {
  padding: 70px 0;
}

.section-soft {
  background: var(--soft);
}

.section-heading {
  max-width: 700px;
  margin-bottom: 32px;
}

.section-heading p {
  margin-bottom: 0;
  color: var(--muted);
}

.grid-3,
.grid-2,
.subject-grid,
.tool-grid {
  display: grid;
  gap: 20px;
}

.grid-3,
.subject-grid,
.tool-grid {
  grid-template-columns: repeat(3, 1fr);
}

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

.card {
  padding: 24px;
}

.lift {
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.lift:hover {
  box-shadow: var(--shadow);
  transform: translateY(-4px);
}

.icon-box {
  display: grid;
  width: 44px;
  height: 44px;
  margin-bottom: 17px;
  place-items: center;
  color: var(--brand);
  background: var(--brand-soft);
  border-radius: 12px;
  font-size: 20px;
}

.icon-box.red {
  color: var(--uadeo);
  background: var(--uadeo-soft);
}

.card p,
.publication p {
  color: var(--muted);
  font-size: 14px;
}

.card-link {
  display: inline-block;
  margin-top: 12px;
  color: var(--brand);
  font-size: 13px;
  font-weight: 800;
  text-decoration: none;
}

.card-link.red {
  color: var(--uadeo);
}

.section-top {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 24px;
}

.publication {
  padding: 22px;
}

.publication-head {
  display: flex;
  gap: 14px;
  align-items: flex-start;
}

.number {
  display: grid;
  width: 39px;
  height: 39px;
  flex: 0 0 auto;
  place-items: center;
  color: #fff;
  background: var(--brand);
  border-radius: 10px;
  font-size: 13px;
  font-weight: 800;
}

.number.red {
  background: var(--uadeo);
}

.publication h3 {
  margin-top: 8px;
  font-size: 16px;
}

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

.small {
  font-size: 13px;
}

.center {
  text-align: center;
}

.video-wrap {
  position: relative;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: #0f172a;
  border-radius: var(--radius) var(--radius) 0 0;
}

.video-wrap iframe {
  position: absolute;
  width: 100%;
  height: 100%;
  border: 0;
}

.video-caption {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  align-items: center;
  justify-content: space-between;
  padding: 18px 22px;
  background: #fff;
  border: 1px solid var(--line);
  border-top: 0;
  border-radius: 0 0 var(--radius) var(--radius);
}

.cta {
  padding: 62px 0;
  color: #fff;
  text-align: center;
  background: linear-gradient(135deg, var(--brand), var(--brand-dark));
}

.cta p {
  max-width: 650px;
  margin-inline: auto;
  color: #bfdbfe;
}

.breadcrumb {
  display: flex;
  gap: 8px;
  align-items: center;
  margin-bottom: 20px;
  color: var(--muted);
  font-size: 12px;
}

.breadcrumb a {
  text-decoration: none;
}

.page-heading {
  max-width: 720px;
}

.page-heading h1 {
  margin-bottom: 10px;
  font-size: clamp(32px, 4vw, 43px);
}

.page-heading p {
  color: var(--muted);
}

.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  max-width: 700px;
  margin: 25px 0;
}

.stat {
  padding: 15px;
  text-align: center;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 12px;
}

.stat strong {
  display: block;
  color: var(--brand);
  font-size: 23px;
}

.stat:nth-child(even) strong {
  color: var(--uadeo);
}

.stat span {
  color: var(--muted);
  font-size: 11px;
}

.filter-button {
  color: #475569;
  background: #fff;
  border: 1px solid var(--line);
  cursor: pointer;
}

.filter-button.active {
  color: #fff;
  background: var(--brand);
  border-color: var(--brand);
}

.count {
  margin: 20px 0;
  color: var(--muted);
  font-size: 14px;
}

.count strong {
  color: var(--text);
}

.publication-list {
  display: grid;
  gap: 15px;
}

.abstract-toggle {
  padding: 0;
  color: var(--brand);
  background: transparent;
  border: 0;
  font-size: 13px;
  font-weight: 800;
  cursor: pointer;
}

.abstract-toggle.red {
  color: var(--uadeo);
}

.abstract-body {
  display: none;
  padding-top: 13px;
  margin-top: 13px;
  color: var(--muted);
  border-top: 1px solid var(--line);
  font-size: 14px;
}

.abstract-body.open {
  display: block;
}

.no-results {
  display: none;
  padding: 44px 10px;
  color: var(--muted);
  text-align: center;
}

.no-results.visible {
  display: block;
}

.notice {
  padding: 20px;
  color: var(--muted);
}

.notice strong {
  color: var(--text);
}

.course-meta,
.course-footer {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  color: var(--muted);
  font-size: 12px;
}

.course-footer {
  padding-top: 13px;
  margin-top: 18px;
  border-top: 1px solid var(--line);
}

.tutoring-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.schedule-row,
.criteria-row {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
  font-size: 14px;
}

.schedule-row:last-child {
  border-bottom: 0;
}

.steps {
  display: grid;
  gap: 13px;
  padding: 0;
  margin: 0;
  list-style: none;
}

.steps li {
  display: flex;
  gap: 11px;
  align-items: flex-start;
  color: var(--muted);
  font-size: 14px;
}

.step-number {
  display: grid;
  width: 24px;
  height: 24px;
  flex: 0 0 auto;
  place-items: center;
  color: #fff;
  background: var(--brand);
  border-radius: 50%;
  font-size: 12px;
  font-weight: 800;
}

.code {
  display: block;
  padding: 11px;
  overflow-x: auto;
  color: #1e293b;
  background: #f1f5f9;
  border-radius: 8px;
  font-size: 12px;
}

.warning {
  padding: 12px;
  color: var(--warning-text);
  background: var(--warning-bg);
  border: 1px solid var(--warning-line);
  border-radius: 9px;
  font-size: 12px;
}

.tool-card {
  display: flex;
  flex-direction: column;
  padding: 0;
  overflow: hidden;
}

.tool-main {
  display: flex;
  flex: 1;
  flex-direction: column;
  padding: 22px;
}

.tool-use {
  flex: 1;
  padding: 12px;
  margin-top: 14px;
  background: var(--soft);
  border: 1px solid var(--line);
  border-radius: 10px;
}

.tool-use p {
  margin-bottom: 0;
  font-size: 12px;
}

.tool-actions {
  display: flex;
  gap: 8px;
  padding: 0 22px 22px;
}

.tool-actions .btn {
  flex: 1;
}

.affiliate-note {
  max-width: 720px;
  padding: 11px 13px;
  color: var(--warning-text);
  background: var(--warning-bg);
  border: 1px solid var(--warning-line);
  border-radius: 9px;
  font-size: 12px;
}

.site-footer {
  padding: 52px 0 24px;
  color: #cbd5e1;
  background: #0f172a;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 0.8fr 1fr;
  gap: 34px;
}

.footer-title {
  margin-bottom: 13px;
  color: #fff;
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.site-footer p,
.site-footer li,
.site-footer a {
  color: #94a3b8;
  font-size: 13px;
}

.site-footer a {
  text-decoration: none;
}

.site-footer a:hover {
  color: #fff;
}

.footer-list {
  padding: 0;
  margin: 0;
  list-style: none;
}

.footer-list li {
  margin: 8px 0;
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 20px;
  justify-content: space-between;
  padding-top: 20px;
  margin-top: 34px;
  border-top: 1px solid #334155;
}

.footer-bottom p,
.footer-bottom a {
  margin: 0;
  color: #64748b;
  font-size: 12px;
}

.legal {
  max-width: 850px;
  margin: 58px auto;
}

.legal article {
  padding: 32px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.legal h2 {
  margin-top: 30px;
  font-size: 21px;
}

.legal li {
  margin: 7px 0;
}

@media (max-width: 850px) {
  .desktop-nav,
  .youtube-top {
    display: none;
  }

  .menu-button {
    display: inline-flex;
  }

  .hero-grid,
  .grid-3,
  .subject-grid,
  .tool-grid,
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .grid-2,
  .tutoring-grid {
    grid-template-columns: 1fr;
  }

  .hero {
    padding: 56px 0;
  }

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

  .footer-grid {
    gap: 20px;
  }
}

@media (max-width: 540px) {
  .brand small {
    display: none;
  }

  .hero-actions .btn,
  .inline-actions .btn {
    width: 100%;
  }

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

  .section,
  .cta {
    padding: 48px 0;
  }

  .legal article {
    padding: 22px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}