/* ===================================================================
   LM-KBC Challenge 2026 — Stylesheet
   Built on Bootstrap 5.3.3. Override and extend only.
   =================================================================== */

/* --- Custom Properties / Theme --- */
:root {
  --color-primary: #1e3a4f;
  --color-primary-light: #2a5270;
  --color-accent: #5a9e8f;
  --color-accent-light: #7bbdae;
  --color-accent-bg: #eef6f4;
  --color-text: #2c3e50;
  --color-text-muted: #6c757d;
  --color-border: #dee2e6;
  --color-surface: #ffffff;
  --color-surface-alt: #f8f9fa;
  --color-hero-start: #1a2f3f;
  --color-hero-end: #2a5270;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,.08);
  --shadow-md: 0 4px 12px rgba(0,0,0,.1);
  --shadow-lg: 0 8px 30px rgba(0,0,0,.12);
  --transition: .2s ease;
}

/* --- Base & Typography --- */
html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  color: var(--color-text);
  background: var(--color-primary);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

p {
  font-size: 1rem;
  line-height: 1.75;
}

@media (min-width: 768px) {
  #content p {
    text-align: justify;
  }
}

h1, h2, h3, h4, h5, h6 {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  font-weight: 600;
  color: var(--color-text);
}

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

a:not(.btn):not(.btn-hero):not(.nav-link-top):not(.hero-link) {
  color: var(--color-accent);
}

a:not(.btn):not(.btn-hero):not(.nav-link-top):not(.hero-link):hover {
  color: var(--color-primary-light);
}

code {
  background: var(--color-accent-bg);
  color: var(--color-primary);
  padding: .15em .4em;
  border-radius: 4px;
  font-size: .875em;
}

pre code {
  background: none;
  padding: 0;
  border-radius: 0;
  font-size: inherit;
}

.dates-table code {
  background: none;
  padding: 0;
  color: var(--color-text);
  font-size: .85rem;
}

pre {
  background: var(--color-surface-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 1.25rem 1.5rem;
  font-size: .875rem;
  line-height: 1.6;
  overflow-x: auto;
}

.container {
  max-width: 1040px;
}

/* --- Header --- */
.site-header {
  background: var(--color-primary);
  padding: 1.5rem 0 1rem;
}

.site-header .logo {
  display: inline-flex;
  align-items: center;
  gap: .85rem;
  border-top: 3px solid var(--color-accent);
  padding-top: 1rem;
}

.site-header .logo a {
  display: inline-flex;
  align-items: center;
  gap: .85rem;
  color: #fff !important;
}

.header-logo-img {
  height: 36px;
  width: auto;
  border-radius: 4px;
}

.header-edition {
  font-size: 1.1rem;
  font-weight: 300;
  letter-spacing: .5px;
  text-transform: uppercase;
  color: rgba(255,255,255,.8);
  line-height: 1.3;
}

.site-header .tagline {
  color: var(--color-accent-light);
  font-weight: 300;
  font-size: 1rem;
}

.site-header .top-nav {
  font-size: .75rem;
  font-weight: 500;
  letter-spacing: .5px;
  text-transform: uppercase;
}

.site-header .top-nav a {
  color: rgba(255,255,255,.75) !important;
  transition: color var(--transition);
}

.site-header .top-nav a:hover {
  color: var(--color-accent-light) !important;
}

.site-header .top-nav .sep {
  color: rgba(255,255,255,.3);
  margin: 0 .35rem;
}

/* --- Hero --- */
.hero {
  background: linear-gradient(135deg, var(--color-hero-start) 0%, var(--color-hero-end) 100%);
  color: #fff;
  text-align: center;
  padding: 4.5rem 0 3rem;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  top: -60%;
  right: -20%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(90,158,143,.12) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.hero::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-accent-light));
}

.hero .edition-badge {
  display: inline-block;
  background: rgba(90,158,143,.2);
  border: 1px solid rgba(90,158,143,.4);
  color: var(--color-accent-light);
  font-size: .8rem;
  font-weight: 600;
  letter-spacing: 1px;
  text-transform: uppercase;
  padding: .35rem 1rem;
  border-radius: 50px;
  margin-bottom: 1.25rem;
}

.hero h1 {
  color: #fff;
  font-size: 2.25rem;
  font-weight: 300;
  letter-spacing: .5px;
  line-height: 1.3;
  margin-bottom: .75rem;
}

.hero .hero-subtitle {
  color: rgba(255,255,255,.8);
  font-size: 1.15rem;
  font-weight: 300;
  margin-bottom: 1.75rem;
  line-height: 1.6;
}

.hero-link {
  color: var(--color-accent-light) !important;
  border-bottom: 1px solid rgba(123,189,174,.4);
  transition: color var(--transition), border-color var(--transition);
}

.hero-link:hover {
  color: #fff !important;
  border-bottom-color: #fff;
}

.hero-actions {
  margin-bottom: 2rem;
}

.btn-hero {
  display: inline-block;
  padding: .65rem 1.75rem;
  border-radius: var(--radius-sm);
  font-size: .875rem;
  font-weight: 500;
  letter-spacing: .5px;
  text-transform: uppercase;
  transition: all var(--transition);
  cursor: pointer;
  margin: .35rem;
}

.btn-hero-primary {
  background: var(--color-accent);
  color: #fff !important;
  border: 2px solid var(--color-accent);
}

.btn-hero-primary:hover {
  background: var(--color-accent-light);
  border-color: var(--color-accent-light);
  color: #fff !important;
}

.btn-hero-outline {
  background: transparent;
  color: #fff !important;
  border: 2px solid rgba(255,255,255,.5);
}

.btn-hero-outline:hover {
  background: rgba(255,255,255,.1);
  border-color: #fff;
  color: #fff !important;
}

/* Hero Facts Strip */
.hero-facts {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  flex-wrap: wrap;
  background: rgba(0,0,0,.2);
  border-radius: var(--radius-md);
  padding: .85rem 1.5rem;
  max-width: 600px;
  margin: 0 auto;
}

.hero-fact {
  font-size: .8rem;
  font-weight: 500;
  letter-spacing: .5px;
  color: rgba(255,255,255,.85);
  white-space: nowrap;
}

.hero-fact i {
  color: var(--color-accent-light);
  margin-right: .35rem;
}

/* --- News Strip --- */
.news-strip {
  background: var(--color-accent);
  color: #fff;
  padding: .65rem 0;
  font-size: .875rem;
  font-weight: 500;
}

.news-strip i {
  opacity: .85;
}

/* --- Main Content Area --- */
#main {
  background: var(--color-surface);
}

section {
  padding: 3.5rem 0;
}

section + section {
  border-top: 1px solid var(--color-border);
}

/* --- Section Titles --- */
.section-heading {
  font-size: 1.75rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 1.5rem;
  line-height: 1.3;
}

.section-heading::after {
  content: "";
  display: block;
  width: 50px;
  height: 3px;
  background: var(--color-accent);
  margin-top: .75rem;
  border-radius: 2px;
}

/* --- In-section Subheadings --- */
section h4 {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-primary);
  margin-top: 2rem;
  margin-bottom: .75rem;
  padding-top: .5rem;
}

section h4:first-of-type {
  margin-top: 1.5rem;
}

/* --- What's New Cards --- */
.new-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.25rem;
  margin-top: 1rem;
}

.new-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  transition: box-shadow var(--transition), transform var(--transition);
}

.new-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.new-card h4 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-primary);
  margin-top: .75rem !important;
  margin-bottom: .5rem;
  padding-top: 0 !important;
}

.new-card p {
  font-size: .9rem;
  color: var(--color-text-muted);
  margin-bottom: 0;
  line-height: 1.6;
}

.new-card-icon {
  width: 42px;
  height: 42px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-accent-bg);
  color: var(--color-accent);
  border-radius: var(--radius-sm);
  font-size: 1.1rem;
}

/* --- How to Participate (Steps) --- */
.steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
  margin-top: 1rem;
  counter-reset: step-counter;
}

.step {
  position: relative;
  padding: 1.5rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: box-shadow var(--transition);
}

.step:hover {
  box-shadow: var(--shadow-sm);
}

.step-num {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-accent);
  color: #fff;
  font-weight: 700;
  font-size: .9rem;
  border-radius: 50%;
  margin-bottom: .75rem;
}

.step h4 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-primary);
  margin-top: 0 !important;
  margin-bottom: .5rem;
  padding-top: 0 !important;
}

.step p {
  font-size: .9rem;
  color: var(--color-text-muted);
  margin-bottom: 0;
  line-height: 1.6;
}

/* --- Content Cards --- */
.content-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 2rem;
  margin-bottom: 1.5rem;
  transition: box-shadow var(--transition);
}

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

.content-card h4 {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 1rem;
  margin-top: 0;
  padding-top: 0;
  color: var(--color-primary);
}

/* --- Example Cards with Cardinality Badges --- */
.example-card {
  padding: 1.5rem;
  position: relative;
}

.cardinality-badge {
  display: inline-block;
  font-size: .7rem;
  font-weight: 600;
  letter-spacing: .5px;
  text-transform: uppercase;
  padding: .2rem .6rem;
  border-radius: 50px;
  margin-bottom: .75rem;
}

.badge-zero {
  background: #fef3cd;
  color: #856404;
}

.badge-one {
  background: var(--color-accent-bg);
  color: var(--color-accent);
}

.badge-many {
  background: #e8eef3;
  color: var(--color-primary-light);
}

/* --- Task Illustration (pure CSS) --- */
.task-illustration {
  background: var(--color-surface-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  margin: 2rem 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.task-node {
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: .75rem 1.25rem;
  font-size: .875rem;
  font-weight: 500;
  text-align: center;
  min-width: 100px;
  position: relative;
}

.task-node.node-subject {
  border-color: var(--color-accent);
  background: var(--color-accent-bg);
}

.task-node.node-lm {
  border-color: var(--color-primary-light);
  background: #e8eef3;
  padding: 1rem 1.5rem;
}

.task-node.node-object {
  border-color: var(--color-accent-light);
}

.task-node .node-label {
  font-size: .65rem;
  font-weight: 600;
  letter-spacing: 1px;
  text-transform: uppercase;
  color: var(--color-text-muted);
  display: block;
  margin-bottom: .25rem;
}

.task-arrow {
  color: var(--color-text-muted);
  font-size: 1.5rem;
  flex-shrink: 0;
}

.task-objects {
  display: flex;
  flex-direction: column;
  gap: .5rem;
}

/* --- Dataset Property Badges --- */
.prop-badge {
  display: inline-block;
  font-size: .7rem;
  font-weight: 600;
  letter-spacing: .3px;
  padding: .15rem .5rem;
  border-radius: 50px;
  margin-right: .25rem;
}

.prop-set {
  background: #e8eef3;
  color: var(--color-primary-light);
}

.prop-null {
  background: #fef3cd;
  color: #856404;
}

.prop-num {
  background: var(--color-accent-bg);
  color: var(--color-accent);
}

/* --- Timeline / Dates Table --- */
.dates-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--color-border);
}

.dates-table thead {
  background: var(--color-surface-alt);
}

.dates-table th {
  font-size: .75rem;
  font-weight: 600;
  letter-spacing: .5px;
  text-transform: uppercase;
  color: var(--color-text-muted);
  padding: .85rem 1.25rem;
  border-bottom: 2px solid var(--color-border);
}

.dates-table td {
  padding: .85rem 1.25rem;
  border-bottom: 1px solid var(--color-border);
  font-size: .95rem;
}

.dates-table tbody tr:last-child td {
  border-bottom: none;
}

.dates-table tbody tr:hover {
  background: var(--color-surface-alt);
}

.date-badge {
  display: inline-block;
  background: var(--color-accent-bg);
  color: var(--color-accent);
  font-weight: 600;
  font-size: .85rem;
  padding: .2rem .65rem;
  border-radius: var(--radius-sm);
}

/* --- Callout / News Box --- */
.callout {
  background: var(--color-surface-alt);
  border-left: 4px solid var(--color-accent);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 1.25rem 1.5rem;
  margin: 1rem 0;
}

.callout-warning {
  border-left-color: #e6a817;
  background: #fffdf5;
}

.callout-info {
  border-left-color: var(--color-accent);
  background: var(--color-accent-bg);
}

/* --- Rule Cards --- */
.rule-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: box-shadow var(--transition);
}

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

.rule-card-header {
  background: var(--color-surface-alt);
  border-bottom: 1px solid var(--color-border);
  padding: .85rem 1.25rem;
  font-size: .95rem;
  font-weight: 600;
  color: var(--color-primary);
}

.rule-card-header i {
  color: var(--color-accent);
  margin-right: .4rem;
}

.rule-card-body {
  padding: 1.25rem;
}

.rule-card-body p {
  font-size: .9rem;
  line-height: 1.6;
  margin-bottom: .75rem;
}

/* --- Submit Cards --- */
.submit-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  text-align: center;
  transition: box-shadow var(--transition), transform var(--transition);
}

.submit-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.submit-card i {
  margin-bottom: .75rem;
}

.submit-card h4 {
  font-size: .9rem;
  font-weight: 600;
  color: var(--color-primary);
  margin-top: .25rem !important;
  margin-bottom: .35rem;
  padding-top: 0 !important;
}

.submit-card p {
  font-size: .8rem;
  color: var(--color-text-muted);
  margin-bottom: 0;
  line-height: 1.5;
}

/* --- Organizer Cards --- */
.organizer-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: box-shadow var(--transition), transform var(--transition);
  height: 100%;
}

.organizer-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-3px);
}

.organizer-card img {
  width: 100%;
  aspect-ratio: 1;
  object-fit: cover;
}

.organizer-card .card-body {
  padding: 1rem 1.25rem;
}

.organizer-card .card-title {
  font-size: .95rem;
  font-weight: 600;
  margin-bottom: .25rem;
}

.organizer-card .card-text {
  font-size: .85rem;
  color: var(--color-text-muted);
}

/* --- Bottom Info Block --- */
.bottom-block {
  background: var(--color-primary);
  color: rgba(255,255,255,.85);
  padding: 3rem 0;
}

.bottom-block h5 {
  color: #fff;
  font-size: .9rem;
  font-weight: 600;
  letter-spacing: .5px;
  text-transform: uppercase;
  margin-bottom: 1rem;
}

.bottom-block p {
  font-size: .9rem;
  color: rgba(255,255,255,.7);
}

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

.bottom-links li {
  margin-bottom: .5rem;
}

.bottom-links a {
  color: rgba(255,255,255,.8) !important;
  font-size: .9rem;
  transition: color var(--transition);
}

.bottom-links a:hover {
  color: var(--color-accent-light) !important;
}

/* --- Footer --- */
.site-footer {
  background: var(--color-primary);
  border-top: 1px solid rgba(255,255,255,.1);
  color: rgba(255,255,255,.7);
  padding: 2rem 0;
  font-size: .8rem;
  text-align: center;
}

.site-footer a {
  color: rgba(255,255,255,.9) !important;
  font-weight: 600;
}

#license-img {
  height: 2.5em;
  opacity: .85;
  transition: opacity var(--transition);
}

#license-img:hover {
  opacity: 1;
}

/* --- Utility --- */
.text-accent {
  color: var(--color-accent) !important;
}

.bg-accent-subtle {
  background: var(--color-accent-bg) !important;
}

/* --- Responsive --- */
@media (max-width: 768px) {
  .hero {
    padding: 3rem 1rem 2.5rem;
  }

  .hero h1 {
    font-size: 1.65rem;
  }

  .hero .hero-subtitle {
    font-size: 1rem;
  }

  .hero-facts {
    gap: .75rem;
    padding: .75rem 1rem;
  }

  .hero-fact {
    font-size: .75rem;
  }

  .header-logo-img {
    height: 30px;
  }

  .header-edition {
    font-size: .9rem;
  }

  section {
    padding: 2.5rem 0;
  }

  .section-heading {
    font-size: 1.4rem;
  }

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

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

  .task-illustration {
    flex-direction: column;
    padding: 1.5rem 1rem;
  }

  .task-arrow {
    transform: rotate(90deg);
  }

  .content-card {
    padding: 1.25rem;
  }
}

@media (max-width: 480px) {
  .new-grid {
    grid-template-columns: 1fr;
  }

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

  .btn-hero {
    display: block;
    width: 100%;
    margin: .35rem 0;
  }

  .hero-facts {
    flex-direction: column;
    gap: .4rem;
    align-items: center;
  }
}