/**
 *  Zeppe-Lin Linux main CSS style
 *  See LICENSE file for license terms and copyright notices.
 */

/* --- Theme Variables --- */
:root {
  --bg: #f7f5f1;
  --txt: #2c2c2c;
  --gld: #b08340;
  --pre: #f0ede6;
  --brd: rgba(176, 131, 64, 0.25);
  --link: #a67c3a;
  --link-hover: #2c2c2c;
  --toc-w: 280px;

  --fs-base: 16px;
  --fs-h1: calc(var(--fs-base) * 2.37);
  --fs-h2: calc(var(--fs-base) * 1.78);
  --fs-h3: calc(var(--fs-base) * 1.33);
  --fs-small: calc(var(--fs-base) * 0.85);

  --rhythm: 1.25rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #1b1b17;
    --txt: #dcd6c9;
    --gld: #e2c07a;
    --pre: #25241f;
    --brd: rgba(226, 192, 122, 0.25);
    --link: #e2c07a;
    --link-hover: #ffffff;
  }
}

/* --- Layout Foundation --- */
html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--txt);
  font-family: ui-monospace, "Cascadia Code", monospace;
  font-size: var(--fs-base);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  font-feature-settings: "liga" 1, "calt" 1, "tnum" 1;
}

/* --- Sidebar TOC --- */
#TOC {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--toc-w);
  height: 100vh;
  padding: calc(var(--rhythm) * 2.5) 1.5rem;
  box-sizing: border-box;
  border-right: 1px solid var(--brd);
  overflow-y: auto;
  font-size: var(--fs-small);
  background: var(--bg);
  z-index: 1000;
}

#TOC ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

/*
#TOC li {
  margin: calc(var(--rhythm) * 0.35) 0;
  line-height: 1.4;
  padding-left: 0.5em;
}
*/
#TOC li {
  margin: calc(var(--rhythm) * 0.5) 0;
  padding-left: 0.5em; /* gentle indent */
}

#TOC ul ul {
  border-left: 1px solid var(--brd);
  margin-left: 0.25em;
  padding-left: 0.75em;
}

#TOC ul ul li {
  padding-left: 1em; /* slightly deeper for nested levels */
}

#TOC a {
  color: var(--link);
  text-decoration: none;
  opacity: 0.85;
  transition: color 0.2s ease, opacity 0.2s ease;
}

#TOC a:hover {
  opacity: 1;
  color: var(--link-hover);
}

/* --- Target highlight --- */
h1, h2, h3 {
  transition: color 0.4s ease, border-bottom-color 0.4s ease;
}

h1:target,
h2:target,
h3:target {
  border-bottom-color: var(--gld);
  color: var(--gld);
}

/* --- Main Container --- */
main {
  margin-left: var(--toc-w);              /* always reserve space for TOC */
  margin-right: auto;
  padding: calc(var(--rhythm) * 3) 2rem;  /* stable horizontal padding */
  max-width: 72ch;                        /* normalized readable width */
  box-sizing: border-box;
}

/* When no TOC is present */
/*
body:not(:has(#TOC)) main {
  margin: 0 auto;
  padding: calc(var(--rhythm) * 3) clamp(1rem, 4vw, 3rem);
  text-align: left;
}
*/

/* --- Headers --- */
h1, h2, h3 {
  margin-top: calc(var(--rhythm) * 2);
  margin-bottom: calc(var(--rhythm) * 0.75);
  border-bottom: 1px solid var(--brd);
  padding-bottom: 0.3rem;
  font-weight: 600;
  letter-spacing: 0.02em;
}

h1 { font-size: var(--fs-h1); color: var(--gld); }
h2 { font-size: var(--fs-h2); color: var(--gld); }
h3 { font-size: var(--fs-h3); color: var(--txt); }

h1::before {
  content: "";
  display: block;
  width: 2.5ch;
  height: 2px;
  background: var(--gld);
  margin-bottom: 0.7rem;
  opacity: 0.45;
}

/* --- Text --- */
p { margin: calc(var(--rhythm) * 1) 0; }
small, .secondary { color: #6e6e6e; font-size: var(--fs-small); }

a {
  color: var(--link);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.15em;
}

a:hover { color: var(--link-hover); }

/* --- Harmonized Markdown Separator --- */
hr {
  border: none;
  height: 1px;
  margin: calc(var(--rhythm) * 2.5) auto;
  max-width: 40ch;
  background:
    linear-gradient(
      to right,
      transparent,
      var(--gld),
      transparent
    );
  opacity: 0.45;
}

/* Optional: tighter separator for dense sections */
section hr {
  margin: calc(var(--rhythm) * 2) auto;
  max-width: 32ch;
  opacity: 0.35;
}

/* --- Code & Pre --- */
code, pre {
  background: var(--pre);
  padding: 0.2em 0.4em;
  border-radius: 4px;
  font-size: var(--fs-small);
  font-variant-numeric: tabular-nums;
}

pre {
  padding: 1rem;
  overflow-x: auto;
}

pre code {
  display: block;
  padding: 0.4rem 0.6rem;
  border-radius: 3px;
  font-family: "Cascadia Mono", monospace;
  white-space: pre;
}

code {
  white-space: nowrap;       /* prevent wrapping entirely */
}

/* --- Tables --- */
table {
  width: 100%;
  border-collapse: collapse;
  margin: calc(var(--rhythm) * 2) 0;
  font-size: var(--fs-small);
  font-family: "Cascadia Mono", monospace;
  font-variant-numeric: tabular-nums;
  border: 1px solid var(--brd);
  border-radius: 6px;          /* rounded corners */
  overflow: hidden;            /* clip child borders to radius */
}

th, td {
  padding: 0.6rem 1rem;
  border-bottom: 1px solid var(--brd);
  text-align: left;
  vertical-align: middle;
}

th {
  background: var(--pre);
  color: var(--gld);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

td {
  color: var(--txt);
}

tr:last-child td {
  border-bottom: none;         /* clean bottom edge */
}

tr:nth-child(even) td {
  background: rgba(176, 131, 64, 0.04);
}

tr:hover td {
  background: rgba(176, 131, 64, 0.08);
}

/* Alignment helpers */
td.num, th.num { text-align: right; }
td.center, th.center { text-align: center; }

/* --- Figures --- */
img {
  max-width: 100%;
  height: auto;
  border: 1px solid var(--brd);
  padding: 5px;
  background: var(--pre);
  margin: calc(var(--rhythm) * 2) auto;
  display: block;
  box-shadow: 6px 6px 0 var(--brd);
  border-radius: 2px;
}

figure {
  margin: calc(var(--rhythm) * 2) 0;
  text-align: center;
}

figcaption {
  margin-top: 0.75rem;
  font-size: var(--fs-small);
  font-style: italic;
  border-top: 1px solid var(--brd);
  padding-top: 0.5rem;
  max-width: 65ch;
  margin-left: auto;
  margin-right: auto;
  opacity: 0.85;
}

/* --- Blockquotes --- */
blockquote {
  margin: calc(var(--rhythm) * 1.5) auto;
  padding: 0.75rem 1.25rem;
  max-width: 65ch;
  font-size: var(--fs-small);
  font-style: italic;
  border-left: 3px solid var(--gld);
  background: var(--pre);
  border-radius: 2px;
  opacity: 0.9;
}

blockquote p { margin: 0; }

blockquote code {
  background: transparent;
  padding: 0;
  border-radius: 0;
  font-size: 0.95em;
  white-space: normal;
  color: var(--txt);
  opacity: 0.75;
  /*
  text-decoration: underline;
  text-decoration-thickness: 0.5px;
  text-underline-offset: 0.15em;
  text-decoration-color: var(--brd);
  */
}

/* --- Blockquote Footer --- */
blockquote footer {
  margin-top: 0.75rem;
  font-size: var(--fs-small);
  font-style: normal;
  color: var(--gld);
  text-align: right;
  border-top: 1px solid var(--brd);
  padding-top: 0.5rem;
  opacity: 0.85;
}

/* --- Responsive --- */
@media screen and (max-width: 1024px) {
  #TOC {
    position: relative;
    width: 100%;
    height: auto;
    border-right: none;
    border-bottom: 1px solid var(--brd);
  }

  main {
    margin: 0 auto;                       /* center content on mobile */
    max-width: 100%;                      /* full width for small screens */
    padding: 2rem 1.25rem;                /* normalized side padding */
  }
}

/* End of file. */