/* Data Center 101. Clean, readable, no framework. */

:root {
  --ink: #1c1e21;
  --ink-soft: #55606b;
  --paper: #fbfaf7;
  --card: #ffffff;
  --line: #e3e0d8;
  --accent: #0b5d68;
  --accent-dark: #083f47;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: Georgia, 'Times New Roman', serif;
  font-size: 1.075rem;
  line-height: 1.65;
}

.wrap {
  max-width: 760px;
  margin: 0 auto;
  padding: 0 1.25rem;
}

/* Header */
.site-header {
  border-bottom: 1px solid var(--line);
  background: var(--card);
}
.site-header .wrap {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  padding-top: 1rem;
  padding-bottom: 1rem;
}
.site-name {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  font-weight: 700;
  font-size: 1.2rem;
  letter-spacing: 0.01em;
  color: var(--ink);
  text-decoration: none;
}
.site-header nav a {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  font-size: 0.95rem;
  color: var(--accent);
  text-decoration: none;
  margin-left: 1.25rem;
}
.site-header nav a:hover { text-decoration: underline; }

/* Homepage */
.intro { padding: 2.5rem 0 0.5rem; }
.intro h1 {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  font-size: 1.85rem;
  line-height: 1.25;
  margin: 0 0 0.75rem;
}
.intro p { color: var(--ink-soft); margin: 0 0 1rem; }

.topic-group { margin: 2.25rem 0; }
.topic-group h2 {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  font-size: 1.05rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--accent-dark);
  border-bottom: 1px solid var(--line);
  padding-bottom: 0.4rem;
  margin: 0 0 1rem;
}
.article-list { list-style: none; margin: 0; padding: 0; }
.article-list li { margin: 0 0 1.4rem; }
.article-list a {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  font-weight: 600;
  font-size: 1.15rem;
  color: var(--accent);
  text-decoration: none;
}
.article-list a:hover { text-decoration: underline; }
.article-list p {
  margin: 0.25rem 0 0;
  font-size: 0.98rem;
  color: var(--ink-soft);
}

/* Article pages */
.article { padding: 2.25rem 0 3rem; }
.article .hero {
  width: 100%;
  height: auto;
  border-radius: 8px;
  margin-bottom: 1.5rem;
  display: block;
}
.kicker {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent-dark);
  margin: 0 0 0.5rem;
}
.article h1 {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  font-size: 2.1rem;
  line-height: 1.2;
  margin: 0 0 0.5rem;
}
.byline {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  font-size: 0.95rem;
  color: var(--ink-soft);
  margin: 0 0 1.75rem;
}
.byline a { color: var(--ink-soft); }
.article h2 {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  font-size: 1.45rem;
  line-height: 1.3;
  margin: 2.25rem 0 0.75rem;
}
.article h3 {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  font-size: 1.15rem;
  margin: 1.75rem 0 0.5rem;
}
.article a { color: var(--accent); }
.article a:hover { color: var(--accent-dark); }
.article img { max-width: 100%; height: auto; border-radius: 8px; }
.article blockquote {
  margin: 1.5rem 0;
  padding: 0.25rem 0 0.25rem 1.25rem;
  border-left: 3px solid var(--accent);
  color: var(--ink-soft);
}
.article ul, .article ol { padding-left: 1.5rem; }
.article li { margin-bottom: 0.5rem; }
.article hr {
  border: none;
  border-top: 1px solid var(--line);
  margin: 2.5rem 0;
}
.article code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.9em;
  background: #f0eee8;
  padding: 0.1em 0.35em;
  border-radius: 4px;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--line);
  background: var(--card);
  margin-top: 2rem;
}
.site-footer .wrap { padding-top: 1.5rem; padding-bottom: 1.75rem; }
.site-footer p {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  font-size: 0.9rem;
  color: var(--ink-soft);
  margin: 0 0 0.4rem;
}
.site-footer a { color: var(--accent); text-decoration: none; }
.site-footer a:hover { text-decoration: underline; }
.footnote { font-size: 0.82rem; }

@media (max-width: 600px) {
  body { font-size: 1.02rem; }
  .intro h1 { font-size: 1.5rem; }
  .article h1 { font-size: 1.65rem; }
  .site-header .wrap { flex-direction: column; gap: 0.35rem; }
  .site-header nav a { margin-left: 0; margin-right: 1.25rem; }
}

/* Contact form (About page). Netlify form; markup lives in build.js. */
.contact-form {
  margin-top: 1.25rem;
  padding: 1.5rem;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 8px;
}
.contact-form .field { margin-bottom: 1.1rem; }
.contact-form label {
  display: block;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--ink);
  margin-bottom: 0.35rem;
}
.contact-form .opt {
  font-weight: 400;
  color: var(--ink-soft);
  font-size: 0.85rem;
}
.contact-form input[type="text"],
.contact-form input[type="email"],
.contact-form select,
.contact-form textarea {
  width: 100%;
  font-family: Georgia, 'Times New Roman', serif;
  font-size: 1rem;
  color: var(--ink);
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 5px;
  padding: 0.6rem 0.7rem;
  line-height: 1.5;
}
.contact-form textarea { resize: vertical; min-height: 8rem; }
.contact-form input:focus,
.contact-form select:focus,
.contact-form textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 2px rgba(11, 93, 104, 0.12);
}
.contact-form .field-row { display: flex; gap: 1rem; }
.contact-form .field-row .field { flex: 1; }
.contact-form .form-note {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  font-size: 0.86rem;
  color: var(--ink-soft);
  margin: 0 0 1.1rem;
}
.contact-form .btn {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  font-size: 0.95rem;
  font-weight: 600;
  color: #fff;
  background: var(--accent);
  border: none;
  border-radius: 5px;
  padding: 0.65rem 1.6rem;
  cursor: pointer;
}
.contact-form .btn:hover { background: var(--accent-dark); }
/* Honeypot. Hidden from people, visible to bots that fill every field. */
.hp-field { position: absolute; left: -9999px; width: 1px; height: 1px; overflow: hidden; }

@media (max-width: 600px) {
  .contact-form { padding: 1.15rem; }
  .contact-form .field-row { flex-direction: column; gap: 0; }
}

/* Topic filter (homepage). Progressive enhancement: sections render visible,
   the script only hides after a click. Markup lives in build.js. */
.topic-filter {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 1.75rem 0 2.25rem;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--line);
}
.tf-btn {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--ink-soft);
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.45rem 0.95rem;
  cursor: pointer;
  transition: border-color 0.12s, color 0.12s, background 0.12s;
}
.tf-btn:hover { border-color: var(--accent); color: var(--accent); }
.tf-btn.is-active {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}
.tf-n {
  font-variant-numeric: tabular-nums;
  font-weight: 500;
  opacity: 0.65;
  margin-left: 0.15rem;
}
.tf-btn.is-active .tf-n { opacity: 0.8; }
.topic-group[hidden] { display: none; }

@media (max-width: 600px) {
  .topic-filter { gap: 0.4rem; margin: 1.25rem 0 1.75rem; }
  .tf-btn { font-size: 0.85rem; padding: 0.4rem 0.8rem; }
}