/* Visual identity replicated from jax-ml/scaling-book (al-folio theme, _sass/_variables.scss + _themes.scss) */
:root {
  --global-bg-color: #ffffff;
  --global-code-bg-color: rgba(181, 9, 172, 0.05);
  --global-text-color: #000000;
  --global-text-color-light: #828282;
  --global-theme-color: #b509ac;
  --global-hover-color: #b509ac;
  --global-hover-text-color: #ffffff;
  --global-divider-color: rgba(0, 0, 0, 0.1);
  --global-highlight-color: #b71c1c;
  --btt-bg: rgba(181, 9, 172, 0.62);
  --btt-text: #ffffff;
}
html[data-theme="dark"] {
  --global-bg-color: #1c1c1d;
  --global-code-bg-color: #2c3237;
  --global-text-color: #d8d8d8;
  --global-text-color-light: #828282;
  --global-theme-color: #2698ba;
  --global-hover-color: #2698ba;
  --global-hover-text-color: #ffffff;
  --global-divider-color: #424246;
  --global-highlight-color: #ff3636;
  --btt-bg: rgba(38, 152, 186, 0.62);
  --btt-text: #000000;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: "Roboto", "Helvetica Neue", Helvetica, Arial, sans-serif;
  font-weight: 400;
  color: var(--global-text-color);
  background: var(--global-bg-color);
  line-height: 1.7;
  font-size: 17px;
}
a { color: var(--global-theme-color); text-decoration: none; }
a:hover { color: var(--global-hover-color); text-decoration: underline; }

/* fixed navbar */
header.navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 50;
  display: flex; align-items: center; gap: 1.25rem;
  padding: 0.6rem 1.5rem;
  background: var(--global-bg-color);
  border-bottom: 1px solid var(--global-divider-color);
}
header.navbar .title { font-size: 1.15rem; font-weight: 500; color: var(--global-text-color); }
header.navbar .title:hover { color: var(--global-theme-color); text-decoration: none; }
header.navbar nav { margin-left: auto; display: flex; align-items: center; gap: 1.1rem; }
header.navbar nav a { color: var(--global-text-color); font-size: 0.95rem; }
header.navbar nav a:hover { color: var(--global-theme-color); text-decoration: none; }
#theme-toggle { background: none; border: none; font-size: 1.15rem; cursor: pointer; color: var(--global-text-color); }
#theme-toggle:hover { color: var(--global-theme-color); }

/* reading progress bar */
#progress {
  position: fixed; top: 0; left: 0; height: 3px; width: 0;
  background: var(--global-theme-color); z-index: 60;
}

main { max-width: 800px; margin: 0 auto; padding: 6.5rem 1.25rem 4rem; }

/* article typography (al-folio-ish) */
article h1 { font-size: 2rem; font-weight: 500; margin: 0 0 1.5rem; line-height: 1.25; }
article h2 {
  font-size: 1.4rem; font-weight: 500; margin: 3rem 0 1rem;
  padding-bottom: 0.35rem; border-bottom: 1px solid var(--global-divider-color);
}
article h3 { font-size: 1.13rem; font-weight: 600; margin: 2.2rem 0 0.8rem; }
article p { margin: 0.9rem 0; }
article ul, article ol { padding-left: 1.5rem; }
article li { margin: 0.35rem 0; }
article code {
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 0.86em; background: var(--global-code-bg-color);
  border-radius: 3px; padding: 0.15em 0.35em;
}
article pre {
  background: var(--global-code-bg-color); border: 1px solid var(--global-divider-color);
  border-radius: 6px; padding: 1rem 1.1rem; overflow-x: auto; line-height: 1.5;
}
article pre code { background: none; padding: 0; font-size: 0.85rem; }
article blockquote {
  margin: 1.2rem 0; padding: 0.4rem 1.1rem; color: var(--global-text-color-light);
  border-left: 4px solid var(--global-theme-color); background: var(--global-code-bg-color);
}
article table { border-collapse: collapse; width: 100%; margin: 1.2rem 0; font-size: 0.92rem; }
article th, article td { border: 1px solid var(--global-divider-color); padding: 0.5rem 0.7rem; text-align: left; }
article th { background: var(--global-code-bg-color); }
article hr { border: none; border-top: 1px solid var(--global-divider-color); margin: 2.5rem 0; }
article img { max-width: 100%; }

/* landing page cards */
.cards { display: grid; gap: 1.25rem; margin-top: 2rem; }
.card {
  display: block; padding: 1.4rem 1.5rem; border: 1px solid var(--global-divider-color);
  border-radius: 8px; color: var(--global-text-color); background: var(--global-bg-color);
  transition: border-color 0.15s ease, transform 0.15s ease;
}
.card:hover { border-color: var(--global-theme-color); text-decoration: none; transform: translateY(-2px); }
.card .card-title { font-weight: 600; font-size: 1.1rem; color: var(--global-theme-color); }
.card p { margin: 0.5rem 0 0; color: var(--global-text-color-light); font-size: 0.95rem; }

/* back to top */
#back-to-top {
  position: fixed; right: 30px; bottom: 30px; width: 40px; height: 40px;
  border-radius: 50%; border: none; cursor: pointer; z-index: 10;
  color: var(--btt-text); background: var(--btt-bg);
  display: none; align-items: center; justify-content: center; font-size: 1.1rem;
}
#back-to-top.visible { display: flex; }

footer {
  border-top: 1px solid var(--global-divider-color); color: var(--global-text-color-light);
  text-align: center; padding: 1.5rem; font-size: 0.85rem;
}