/* ============================================
   Complete Spanish Course — Main Stylesheet
   Light/Dark mode via CSS custom properties
   ============================================ */

/* ---------- Reset (minimal) ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

/* ---------- Theme tokens ---------- */
:root {
  --bg:          #f8fafc;
  --bg-card:     #ffffff;
  --bg-code:     #f1f5f9;
  --bg-header:   #3b82f6;
  --text:        #334155;
  --text-muted:  #64748b;
  --text-heading:#ffffff;
  --accent:      #3b82f6;
  --accent2:     #4ecdc4;
  --border:      #e2e8f0;
  --shadow:      rgba(0,0,0,.08);
  --nav-bg:      #1e293b;
  --nav-text:    #f1f5f9;
  --code-color:  #16a34a;
  --link:        #3b82f6;
  --blockquote-bg:#e2e8f0;
  --table-border:#cbd5e1;
  --table-stripe:#f8fafc;
  --toggle-bg:   #cbd5e1;
}

[data-theme="dark"] {
  --bg:          #0f172a;
  --bg-card:     #1e293b;
  --bg-code:     #1e293b;
  --bg-header:   #1d4ed8;
  --text:        #e2e8f0;
  --text-muted:  #94a3b8;
  --text-heading:#ffffff;
  --accent:      #60a5fa;
  --accent2:     #2dd4bf;
  --border:      #334155;
  --shadow:      rgba(0,0,0,.3);
  --nav-bg:      #0f172a;
  --nav-text:    #e2e8f0;
  --code-color:  #4ade80;
  --link:        #60a5fa;
  --blockquote-bg:#1e293b;
  --table-border:#475569;
  --table-stripe:#1e293b;
  --toggle-bg:   #475569;
}

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

body {
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  font-size: 1rem;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
  padding: 0;
  margin: 0;
  transition: background .3s, color .3s;
}

/* ---------- Site header / nav ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--nav-bg);
  color: var(--nav-text);
  padding: .6rem 1.2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: .5rem;
  box-shadow: 0 2px 8px var(--shadow);
}

.site-header a {
  color: var(--nav-text);
  text-decoration: none;
  font-size: .9rem;
  padding: .35rem .7rem;
  border-radius: 6px;
  transition: background .2s;
}
.site-header a:hover { background: rgba(255,255,255,.12); }
.site-header .nav-links { display: flex; align-items: center; gap: .25rem; flex-wrap: wrap; }
.site-header .site-brand { font-weight: 700; font-size: 1.05rem; white-space: nowrap; }

/* Dark mode toggle */
.theme-toggle {
  background: var(--toggle-bg);
  border: none;
  border-radius: 999px;
  width: 52px;
  height: 28px;
  cursor: pointer;
  position: relative;
  transition: background .3s;
  flex-shrink: 0;
}
.theme-toggle::after {
  content: '';
  position: absolute;
  top: 3px; left: 3px;
  width: 22px; height: 22px;
  border-radius: 50%;
  background: #fff;
  transition: transform .3s;
  box-shadow: 0 1px 3px rgba(0,0,0,.2);
}
[data-theme="dark"] .theme-toggle { background: #3b82f6; }
[data-theme="dark"] .theme-toggle::after { transform: translateX(24px); }
.theme-toggle-label {
  display: flex; align-items: center; gap: .4rem; cursor: pointer;
  font-size: .85rem; color: var(--nav-text); user-select: none;
}
.theme-toggle-label .icon { font-size: 1rem; }

/* ---------- Content wrapper ---------- */
.content-wrap {
  max-width: 960px;
  margin: 0 auto;
  padding: 1.5rem 1.25rem 3rem;
}

/* ---------- Typography ---------- */
h1, h2, h3, h4 {
  font-weight: 700;
  line-height: 1.3;
  color: var(--text-heading);
  background: var(--bg-header);
  padding: .75rem 1rem;
  margin: 1.5rem 0 .75rem;
  border-radius: 8px;
}
h1 { font-size: 1.75rem; text-align: center; }
h2 { font-size: 1.35rem; }
h3 { font-size: 1.15rem; }
h4 { font-size: 1.05rem; }

p  { margin: .75rem 0; }
strong { font-weight: 700; color: var(--text); }
a  { color: var(--link); transition: color .2s; }
a:hover { text-decoration: underline; }

/* ---------- Lists ---------- */
ol, ul { margin: .5rem 0 .5rem 1.75rem; }
ol li { list-style: decimal; padding: .3rem 0; }
ul li { list-style: disc;    padding: .3rem 0; }
dl { margin: .5rem 0 .5rem 1.75rem; }
dd { margin-left: 1.25rem; padding-bottom: .5rem; }

/* ---------- Code ---------- */
code, pre {
  font-family: 'Fira Code', 'Cascadia Code', 'Courier New', monospace;
  color: var(--code-color);
  background: var(--bg-code);
  border-radius: 4px;
}
code { padding: .15rem .35rem; font-size: .9em; }
pre  { padding: 1rem; overflow-x: auto; margin: 1rem 0; line-height: 1.55; }
pre code { padding: 0; background: transparent; }

.code-comment { color: #0891b2; font-style: italic; }
.comment-block { border-left: 4px solid var(--accent); padding: .6rem 1rem; margin: 1rem 0; border-radius: 0 6px 6px 0; background: var(--bg-code); }

/* ---------- Tables ---------- */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem auto;
  font-size: .95rem;
}
th, td {
  border: 1px solid var(--table-border);
  padding: .55rem .75rem;
  text-align: center;
}
th { background: var(--accent); color: #fff; font-weight: 600; }
tr:nth-child(even) td { background: var(--table-stripe); }

/* ---------- Blockquote ---------- */
blockquote {
  margin: 1rem 0;
  padding: .85rem 1.25rem;
  background: var(--blockquote-bg);
  border-left: 4px solid var(--accent);
  border-radius: 0 8px 8px 0;
  color: var(--text);
}

/* ---------- Images & SVG ---------- */
img { max-width: 100%; height: auto; border-radius: 6px; }
svg { display: block; margin: 1rem auto; max-width: 100%; }

/* ---------- Mermaid diagrams ---------- */
.mermaid, .mermaid_container, .mermaid-diagram {
  margin: 1.5rem auto;
  padding: 1rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 8px;
  max-width: 100%;
  text-align: center;
  overflow-x: auto;
}
.mermaid svg { margin: 0 auto; display: block; }

/* ---------- Tip / info boxes ---------- */
.tip-box, .info-box, .warning-box {
  margin: 1rem 0;
  padding: 1rem 1.25rem;
  border-radius: 8px;
  border-left: 4px solid var(--accent2);
  background: var(--bg-card);
  box-shadow: 0 1px 4px var(--shadow);
}
.tip-box h3, .info-box h3, .warning-box h3 {
  background: transparent;
  color: var(--accent2);
  padding: 0;
  margin: 0 0 .4rem;
  font-size: 1.05rem;
}

/* ---------- Canvas (vowel charts etc.) ---------- */
canvas { display: block; margin: 1rem auto; max-width: 100%; }

/* ---------- Prev / Next nav ---------- */
.lesson-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  margin: 2.5rem 0 1rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  flex-wrap: wrap;
}
.lesson-nav a {
  display: inline-flex;
  align-items: center;
  gap: .35rem;
  padding: .6rem 1rem;
  background: var(--accent);
  color: #fff;
  border-radius: 8px;
  text-decoration: none;
  font-weight: 600;
  font-size: .9rem;
  transition: background .2s, transform .15s;
}
.lesson-nav a:hover { background: var(--accent2); transform: translateY(-1px); }
.lesson-nav .spacer { flex: 1; }

/* ---------- Footer ---------- */
.site-footer {
  text-align: center;
  padding: 1.5rem 1rem;
  font-size: .85rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border);
  margin-top: 2rem;
}
.site-footer a { color: var(--link); }

/* ==========================================
   INDEX PAGE — card grid & progress tracker
   ========================================== */
.index-hero {
  text-align: center;
  padding: 2rem 1rem;
}
.index-hero h1 {
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  font-size: clamp(1.75rem, 5vw, 2.75rem);
  padding: 0;
  margin-bottom: .25rem;
}
.index-hero .subtitle {
  color: var(--text-muted);
  font-size: 1.1rem;
}

.intro-section {
  background: var(--bg-card);
  border-radius: 12px;
  padding: 1.75rem;
  margin-bottom: 2rem;
  text-align: center;
  box-shadow: 0 2px 8px var(--shadow);
  border: 1px solid var(--border);
}
.intro-section h2 { background: transparent; color: var(--accent); padding: 0; margin: 0 0 .75rem; }

.progress-tracker {
  background: var(--bg-card);
  border-radius: 12px;
  padding: 1.5rem;
  margin-bottom: 2rem;
  box-shadow: 0 2px 8px var(--shadow);
  border: 1px solid var(--border);
}
.progress-tracker h3 { background: transparent; color: var(--accent); padding: 0; margin: 0 0 .5rem; font-size: 1.15rem; }
.progress-bar {
  width: 100%;
  height: 26px;
  background: var(--border);
  border-radius: 13px;
  overflow: hidden;
  margin: .75rem 0;
}
.progress-fill {
  height: 100%;
  background: linear-gradient(to right, var(--accent), var(--accent2));
  width: 0%;
  transition: width .5s;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 700;
  font-size: .8rem;
}

.course-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.25rem;
  margin-bottom: 2rem;
}

.lesson-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.25rem;
  text-decoration: none;
  color: var(--text);
  display: flex;
  flex-direction: column;
  gap: .4rem;
  transition: transform .2s, box-shadow .2s, border-color .2s;
  box-shadow: 0 1px 4px var(--shadow);
}
.lesson-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 6px 20px var(--shadow);
  border-color: var(--accent);
}

.lesson-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px; height: 36px;
  border-radius: 50%;
  background: var(--accent2);
  color: #fff;
  font-weight: 700;
  font-size: .9rem;
  flex-shrink: 0;
}

.lesson-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text);
}
.lesson-description { font-size: .9rem; color: var(--text-muted); }
.lesson-topics      { font-size: .8rem; color: var(--text-muted); }

.lesson-card.special-lesson {
  background: linear-gradient(135deg, #667eea, #764ba2);
  border-color: transparent;
  color: #fff;
}
.lesson-card.special-lesson .lesson-number { background: #fff; color: #667eea; }
.lesson-card.special-lesson .lesson-title,
.lesson-card.special-lesson .lesson-description,
.lesson-card.special-lesson .lesson-topics { color: #fff; }

/* ---------- Responsive ---------- */
@media (max-width: 600px) {
  .site-header { padding: .5rem .75rem; }
  .site-header .site-brand { font-size: .9rem; }
  .content-wrap { padding: 1rem .75rem 2rem; }
  h1 { font-size: 1.4rem; }
  h2 { font-size: 1.15rem; }
  .course-grid { grid-template-columns: 1fr; }
  .lesson-nav { flex-direction: column; align-items: stretch; text-align: center; }
  .lesson-nav a { justify-content: center; }
  table { font-size: .85rem; }
  th, td { padding: .4rem; }
}

/* BEGIN footer-nav-styles (managed by add_footer_nav.py) */
/* Home-link: outlined "ghost" variant to distinguish from prev/next */
.lesson-nav .home-link {
    background: transparent;
    color: var(--accent);
    border: 2px solid var(--accent);
}
.lesson-nav .home-link:hover {
    background: var(--accent);
    color: #fff;
    transform: translateY(-1px);
}

/* First lesson uses <span></span> as a prev placeholder; keep it inert */
.lesson-nav > span:empty { flex: 0 0 auto; }

.site-footer p { margin: .35rem 0; }

.footer-links {
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
    margin-top: .5rem;
}
.site-footer .footer-links a { text-decoration: none; }
.site-footer .footer-links a:hover { text-decoration: underline; }
/* END footer-nav-styles */