/* =========================
   1. RESET
========================= */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

/* =========================
   2. VARIABLES
========================= */
:root {
  --color-primary: #6a0000;
  --color-text: #222;
  --color-muted: #666;
  --bg-light: #f8f8f8;

  --max-width: 1200px;

  --space-xs: 8px;
  --space-sm: 16px;
  --space-md: 32px;
  --space-lg: 64px;
}

/* =========================
   3. BASE
========================= */
body {
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.7;
  font-size: 16px;
}

img {
  max-width: 100%;
  display: block;
}

p {
  margin-bottom: var(--space-sm);
}

ul,
ol {
  margin: var(--space-xs) 0 var(--space-sm) 0;
}

p + ul,
p + ol {
  margin-top: var(--space-xs);
}

h2 {
  font-size: 26px;
  margin-top: var(--space-md);
  margin-bottom: var(--space-sm);
}

h3 {
  font-size: 20px;
  margin-top: var(--space-md);
  margin-bottom: var(--space-xs);
  color: var(--color-primary);
}

/* =========================
   4. LAYOUT
========================= */
.layout {
  display: flex;
  align-items: flex-start;
  min-height: 100vh;
}

.container {
  width: 90%;
  max-width: var(--max-width);
  margin: auto;
}

.content {
  flex: 1;
  min-width: 0;
  padding: 0 var(--space-lg);
}

.grid {
  display: grid;
  gap: var(--space-md);
}

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

.flex {
  display: flex;
}

.flex-center {
  display: flex;
  align-items: center;
  justify-content: center;
}

/* =========================
   5. COMPONENTS
========================= */

/* Button */
.btn {
  display: inline-block;
  padding: 12px 24px;
  background: var(--color-primary);
  color: white;
  text-decoration: none;
  border-radius: 4px;
  transition: 0.2s;
}

.btn:hover {
  opacity: 0.85;
}

/* Card */
.card {
  background: white;
  border: 1px solid rgba(0,0,0,0.06);
  border-radius: 10px;
  padding: var(--space-sm);
  box-shadow: 0 2px 10px rgba(0,0,0,0.04);
}

/* =========================
   6. HEADER
========================= */
.header {
  background: var(--color-primary);
  color: white;
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-sm) 0;
}

.header img {
  width: 80px;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-weight: bold;
  font-size: 24px;
}

.navigation a {
  margin-left: var(--space-md);
  color: white;
  text-decoration: none;
}

.navigation a:hover {
  opacity: 0.8;
}

/* =========================
   7. HERO
========================= */
.hero {
  position: relative;
}

.hero-image img {
  width: 100%;
  height: 500px;
  object-fit: cover;
}

.hero-content {
  position: absolute;
  top: 50%;
  left: 5%;
  transform: translateY(-50%);
  max-width: 500px;
  color: white;
}

.hero h1 {
  font-size: 36px;
  margin-bottom: var(--space-md);
}

/* =========================
   8. PROJECT
========================= */
.section {
  padding: var(--space-sd) 0;
}

.section-title {
  font-size: 40px;
  color: var(--color-primary);
  padding-top: var(--space-md);
  font-weight: 700;
  letter-spacing: -0.5px;
}

.section-divider {
  height: 2px;
  background: linear-gradient(90deg, var(--color-primary), transparent);
  width: 300px;
  border-radius: 2px;
}

.project-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-lg);
  align-items: center;
}

.project p {
  font-size: 18px;
}

.video {
  width: 100%;
  border-radius: 6px;
}

/* =========================
   9. TEAM
========================= */
.team-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-md);
}

.team-member {
  text-align: center;
}

.team-member img {
  height: 250px;
  object-fit: cover;
  border-radius: 6px;
}

.team-description {
  margin-top: var(--space-md);
  text-align: center;
  font-size: 18px;
}

/* =========================
   10. FOOTER
========================= */
.footer {
  background: var(--color-primary);
  color: white;
  padding: var(--space-md) 0;
  text-align: center;
}

.footer-wave svg {
  display: block;
  width: 100%;
}

/* =========================
   11. RESPONSIVE
========================= */
@media (max-width: 900px) {

  .grid-3 {
    grid-template-columns: 1fr;
  }

  .project-content {
    grid-template-columns: 1fr;
  }

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

  .hero-content {
    position: static;
    transform: none;
    padding: var(--space-md);
    background: rgba(0,0,0,0.5);
  }

  .hero-image img {
    height: 300px;
  }
}

/* =========================
   12. ARCHITECTURE
========================= */

.arch-card {
  text-decoration: none;
  color: inherit;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.arch-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 25px rgba(0,0,0,0.1);
}

.arch-content {
  padding: var(--space-sm);
}

.arch-content h2 {
  color: var(--color-primary);
  margin-bottom: var(--space-xs);
}

.arch-content p {
  font-size: 14px;
  color: var(--color-muted);
}

/* =========================
   13. DOCUMENTATION UTILS
========================= */

.doc-list {
  padding-left: 20px;
}

.doc-list li {
  margin-left: var(--space-xs);
  padding-left: 18px;
}

.doc-block {
  background: #ffffff;
  padding: var(--space-xs);
  border-left: 4px solid var(--color-primary);
  margin: var(--space-sm) 0;
  border-radius: 6px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}

/* =========================
   14. TABLE
========================= */

.table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--space-md) 0;
  font-size: 15px;
  border-radius: 8px;
  overflow: hidden;
}

.table th,
.table td {
  text-align: left;
  padding: var(--space-sm);
  border-bottom: 1px solid #ddd;
}

.table th {
  background: var(--bg-light);
  color: var(--color-primary);
  font-weight: bold;
}

.table tr:hover {
  background: rgba(106, 0, 0, 0.05);
}

.table-compact th,
.table-compact td {
  padding: var(--space-xs);
  font-size: 14px;
}

pre {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  font-size: 13px;
  line-height: 1.5;
  overflow-x: auto;
  padding: var(--space-sm);
  border-radius: 8px;
}

/* =========================
   SIDEBAR
========================= */

.sidebar {
  position: sticky;
  top: 80px;
  width: 260px;
  height: calc(100vh - 80px);

  overflow-y: auto;

  padding: var(--space-md);
  border-right: 1px solid rgba(0,0,0,0.08);
  background: #fff;
}

.sidebar h3 {
  font-size: 18px;
  color: var(--color-primary);
}
.sidebar ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.sidebar li {
  margin-bottom: var(--space-xs);
}

.sidebar a {
  display: block;
  padding: 3px 3px;

  font-size: 14px;
  color: var(--color-text);
  text-decoration: none;

  border-radius: 6px;
  transition: background 0.2s ease, color 0.2s ease;
}

.sidebar a:hover {
  background: rgba(106, 0, 0, 0.06);
  color: var(--color-primary);
}

.sidebar a.active {
  color: var(--color-primary);
  font-weight: 600;
  background: rgba(106, 0, 0, 0.08);

  border-left: 3px solid var(--color-primary);
  padding-left: 7px; /* compense border-left */
}

.toc-sub {
  margin-left: var(--space-sm);
  padding-left: var(--space-xs);
  border-left: 1px solid rgba(0, 0, 0, 0.06);
}

.toc-sub a {
  font-size: 13px;
  color: var(--color-muted);
}

.sidebar {
  scrollbar-width: thin;
  scrollbar-color: rgba(0,0,0,0.2) transparent;
}

.sidebar::-webkit-scrollbar {
  width: 6px;
}

.sidebar::-webkit-scrollbar-thumb {
  background: rgba(0,0,0,0.2);
  border-radius: 10px;
}

.link {
  color: var(--color-primary);
  text-decoration: none;
  border-bottom: 1px solid rgba(106, 0, 0, 0.35);
  transition: color 0.2s ease, border-color 0.2s ease;
}

.link:hover {
  color: #4a0000;
  border-bottom-color: var(--color-primary);
}

.chip {
  display: inline-flex;
  align-items: center;

  padding: 2px 8px;
  border-radius: 6px;

  font-size: 13px;
  font-weight: 500;

  color: var(--color-primary);
  background: rgba(106, 0, 0, 0.08);
  border: 1px solid rgba(106, 0, 0, 0.15);

  line-height: 1.4;
}

.math-block {
  display: flex;
  flex-direction: column;
  align-items: center;

  gap: var(--space-xs);

  margin: var(--space-sm) 0;
  padding: var(--space-sm);

  font-family: ui-serif, Georgia, "Times New Roman", serif;
  font-style: italic;
  font-size: 18px;

  text-align: center;
}

.math-line {
  line-height: 1.6;
}