/* =====================================================
   BASE STYLES
   ===================================================== */

:root {
  --bg: #ffffff;
  --text: #1a1a1a;
  --sidebar-bg: #f7f7f7;
  --border: #ddd;
  --accent: #6aa0ff;
  --sidebar-width: 260px;
} 

/* Dark mode */
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #1a1a1a;
    --text: #e0e0e0;
    --sidebar-bg: #2a2a2a;
    --border: #444;
    --accent: #8bb3ff;
  }
}

body {
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  line-height: 1.6;
  margin: 0;
  color: var(--text);
  background: var(--bg);
}

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


/* =====================================================
   LAYOUT SYSTEMS
   ===================================================== */

/* Global container spacing (base layout only) */
.layout-base header,
.layout-base main,
.layout-base footer {
  max-width: 900px;
  margin: 0 auto;
  padding: 24px;
}

/* Teaching Layout (with sidebar) */
.layout-teaching {
  display: grid;
  grid-template-columns: var(--sidebar-width) minmax(0, 1fr);
  column-gap: 24px;
  min-height: 100vh;
  align-items: start;
}

/* Sidebar styles live under COMPONENTS for clarity */ 

.main-column {
  min-width: 0; /* allow content to shrink on small screens */
  display: flex;
  flex-direction: column;
}

.content-area {
  padding: 2rem 3rem;
  max-width: 900px;
  margin: 0 auto;
}


/* =====================================================
   COMPONENTS
   ===================================================== */

/* Header */
header {
  border-bottom: 1px solid #e7e7e7;
}

/* Navigation (base layout only) */
.layout-base nav ul {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  padding: 0;
  margin: 12px 0 0;
}

.layout-base nav a {
  text-decoration: none;
  color: #1a1a1a;
  padding: 6px 10px;
  border-radius: 6px;
}

.layout-base nav a[aria-current="page"] {
  background: #f0f0f0;
  font-weight: 600;
}

/* Sidebar navigation items */
.sidebar-nav ul {
  list-style: none;
  padding: 0;
  margin: 1rem 0;
}

.sidebar-nav li {
  margin-bottom: 0.5rem;
}

.sidebar-nav a {
  display: block;
  padding: 0.2rem 0.3rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  text-decoration: none;
  color: var(--text);
  background: transparent;
  transition: background 0.2s, border-color 0.2s;
}

.sidebar-nav a:hover {
  background: rgba(0,0,0,0.04);
  border-color: var(--border);
}

.sidebar-nav li.active a {
  background: var(--accent);
  border-color: var(--accent);
  font-weight: 600;
  color: #fff;
} 

/* Sidebar container */
.sidebar {
  width: var(--sidebar-width);
  min-width: var(--sidebar-width);
  max-width: var(--sidebar-width);
  background: var(--sidebar-bg);
  padding: 2rem 1.5rem;
  border-right: 1px solid var(--border);
  position: relative;
  height: auto;
  overflow: visible;
} 

/* Sidebar title */
.sidebar-title {
  margin-top: 0;
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
  color: var(--text);
} 


/* Article Components */
.article-header {
  margin-bottom: 2rem;
}

.subtitle {
  color: #666;
  margin-top: -1rem;
}

.article-footer {
  margin-top: 3rem;
  text-align: center;
  color: #888;
  font-size: 0.9rem;
}

/* Site footer */
.site-footer {
  box-sizing: border-box;
  width: 100%;
  border-top: 1px solid var(--border);
  padding: 24px 0; /* vertical padding only; inner container handles horizontal padding */
  color: #666;
  font-size: 0.95rem;
  margin-top: 2rem; /* space above footer only */
}

.site-footer-inner {
  max-width: 900px; /* align with main content width */
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  justify-content: flex-end; /* right-aligned footer content */
  align-items: center;
  gap: 1rem;
}

.site-footer p {
  margin: 0;
}

/* Cookie banner */
.cookie-banner {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0,0,0,0.85);
  color: #fff;
  padding: 14px 0;
  z-index: 9999;
  display: none;
}

.cookie-banner.show,
.cookie-banner[aria-hidden="false"] {
  display: block;
}

.cookie-inner {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.cookie-inner p { margin: 0; font-size: 0.95rem; opacity: 0.95; }

.cookie-inner a { color: #fff; text-decoration: underline; }

.cookie-actions { display: flex; gap: 0.5rem; align-items: center; }

.cookie-accept {
  background: var(--accent);
  color: #fff;
  border: none;
  padding: 8px 12px;
  border-radius: 6px;
  cursor: pointer;
}

.cookie-accept:focus { outline: 2px solid #fff; outline-offset: 2px; }

@media (max-width: 600px) {
  .cookie-inner { flex-direction: column; align-items: flex-start; }
  .cookie-actions { width: 100%; justify-content: flex-end; }
}

/* Sticky sidebar only on wider screens */
@media (min-width: 900px) {
  .sidebar {
    position: sticky;
    top: 0;
    height: 100vh;
    overflow-y: auto;
  }
}

/* Stack layout on small screens */
@media (max-width: 600px) {
  .layout-teaching {
    grid-template-columns: 1fr;
  }
  .sidebar {
    width: 100%;
    min-width: 0;
    max-width: none;
    position: relative;
    height: auto;
  }
}

/* =====================================================
   IMAGE UTILITIES
   ===================================================== */

/* Size variants */
.img-smallest { width: 100px; height: auto; }
.img-smaller { width: 150px; height: auto; }
.img-small { width: 200px; height: auto; }
.img-medium { width: 400px; height: auto; }
.img-large { width: 800px; height: auto; }

/* Hero image */
.hero {
  width: 100%;
  height: auto;
  margin: 2rem 0;
  border-radius: 6px;
}

/* Positioning utilities */
.float-right {
  float: right;
  margin: 0 0 1rem 1rem;
}

.float-left {
  float: left;
  margin: 0 1rem 1rem 0;
}

/* Center an image utility (use on the <img> element) */
.float-center {
  display: block;
  margin: 1.5rem auto;
  clear: both;
}

/* Support `.img-center` as wrapper or image */
.img-center {
  text-align: center;
  margin: 2rem 0;
}

img.img-center,
.img-center img {
  display: block;
  margin: 0 auto;
}

/* Gallery layouts */
.gallery img {
  margin: 0.5rem;
}

.img-row {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin: 1.5rem 0;
}

.img-row img {
  flex: 1 1 250px;
  width: 100%;
  max-width: 250px;
  height: auto;
  border-radius: 4px;
  object-fit: cover;
}


/* =====================================================
   MEDIA QUERIES
   ===================================================== */

@media (max-width: 800px) {
  .img-large {
    width: 100%;
    max-width: 800px;
  }
}

@media (max-width: 480px) {
  .img-smallest,
  .img-smaller,
  .img-small,
  .img-medium {
    width: 100%;
    max-width: none;
  }
}