/* ============================================
   zihao-site -- Personal Site Stylesheet
   Namespace: site-
   ============================================ */

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 14px;
  line-height: 1.7;
  color: #1a1a1a;
  background: #fff;
}

/* ── Outer centering shell ── */
#site-wrap {
  display: grid;
  grid-template-columns: 200px 1fr;
  max-width: 1200px;
  margin: 0 auto;
  padding-top: 120px;
  min-height: 100vh;
}

/* ── Left sidebar ── */
#site-nav {
  position: fixed;
  /* Aligns the sidebar to where it sits inside the centered 960px wrap */
  left: max(0px, calc(50vw - 600px));
  top: 120px;
  width: 200px;
  padding: 0 32px 40px 0;
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  text-align: right;
}

.site-nav-name {
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
  color: #1a1a1a;
  line-height: 1.3;
  margin-bottom: 32px;
}

.site-nav-meta {
  font-size: 11px;
  color: #aaa;
  line-height: 1.5;
  margin-bottom: 40px;
}

.site-nav-links {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.site-nav-link {
  font-size: 13px;
  text-decoration: none;
  color: #888;
  transition: color 0.15s;
}
.site-nav-link:hover {
  color: #1a1a1a;
  text-decoration: underline;
  text-underline-offset: 3px;
}
.site-nav-link.active {
  color: #1a1a1a;
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ── Main content ── */
#site-main {
  grid-column: 2;
  padding: 0 60px 80px 60px;
  max-width: 720px;
}

/* ── Section label ── */
.site-label {
  font-size: 9px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: #aaa;
  margin-bottom: 20px;
  display: block;
}

/* ── Page title ── */
.site-title {
  font-size: 24px;
  font-weight: 700;
  letter-spacing: 0.01em;
  margin-bottom: 8px;
  line-height: 1.2;
}

.site-subtitle {
  font-size: 13px;
  color: #888;
  margin-bottom: 40px;
}

/* ── Rule ── */
.site-rule {
  border: none;
  border-top: 1px solid #e0e0e0;
  margin: 32px 0;
}

/* ── Course card grid (teaching/index.html) ── */
.course-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 16px;
  margin-top: 24px;
}

.course-card {
  display: block;
  position: relative;
  border: 1px solid #e0e0e0;
  border-radius: 6px;
  padding: 20px;
  text-decoration: none;
  color: #1a1a1a;
  transition: border-color 0.15s, box-shadow 0.15s;
}
.course-card:hover {
  border-color: #1a1a1a;
  box-shadow: 0 2px 8px rgba(0,0,0,0.06);
}

.course-card-code {
  font-family: 'Courier New', monospace;
  font-size: 9px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  background: #1a1a1a;
  color: #fff;
  padding: 2px 7px;
  border-radius: 3px;
  display: inline-block;
  margin-bottom: 10px;
}

.course-card-title {
  font-size: 14px;
  font-weight: 700;
  margin-bottom: 4px;
  line-height: 1.3;
}

.course-card-meta {
  font-size: 11px;
  color: #888;
}

.course-card-ext {
  position: absolute;
  top: 12px;
  right: 14px;
  font-size: 18px;
  color: #888;
  font-weight: 700;
  line-height: 1;
}

.course-card.placeholder {
  opacity: 0.4;
  pointer-events: none;
}

/* ── Placeholder page content ── */
.site-placeholder {
  padding: 80px 0;
  color: #bbb;
}
.site-placeholder .site-title { color: #bbb; }

/* ── Mobile ── */
@media (max-width: 700px) {
  #site-wrap {
    grid-template-columns: 1fr;
    padding-top: 0;
  }

  #site-nav {
    position: static;
    left: auto;
    top: auto;
    width: 100%;
    flex-direction: column;
    align-items: flex-start;
    text-align: left;
    padding: 32px 24px 24px;
    border-bottom: 1px solid #e0e0e0;
  }

  .site-nav-name { margin-bottom: 20px; }
  .site-nav-meta { margin-bottom: 20px; }

  .site-nav-links {
    flex-direction: row;
    flex-wrap: wrap;
    gap: 16px;
  }

  #site-main {
    grid-column: 1;
    padding: 32px 24px 60px;
    max-width: 100%;
  }

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