/* ===================================================================
   THE HTML CODEX — style.css
   =================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;500;700&family=JetBrains+Mono:wght@400;500;700&display=swap');

:root {
  --bg: #0d0d0d;
  --fg: #f8f8f8;
  --muted: #8a8a8a;
  --accent: #CCFF00;
  --accent-2: #FF6B00;
  --border: #f8f8f8;
  --card: #1a1a1a;
  --shadow-offset: 6px;
  --mono: 'JetBrains Mono', ui-monospace, monospace;
  --sans: 'Space Grotesk', sans-serif;
}

html[data-theme="light"] {
  --bg: #f8f8f8;
  --fg: #0d0d0d;
  --muted: #555555;
  --accent: #FF6B00;
  --accent-2: #CCFF00;
  --border: #0d0d0d;
  --card: #ffffff;
}

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

html { scroll-behavior: smooth; scroll-padding-top: 100px; }

body {
  margin: 0;
  background-color: var(--bg);
  background-image: 
    linear-gradient(rgba(248, 248, 248, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(248, 248, 248, 0.03) 1px, transparent 1px);
  background-size: 32px 32px;
  color: var(--fg);
  font-family: var(--mono);
  font-size: 15px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--sans);
  font-weight: 700;
  line-height: 1.05;
  margin: 0 0 1rem;
  text-transform: uppercase;
  letter-spacing: -0.02em;
}

code, pre, kbd, samp { font-family: var(--mono); font-size: 0.9em; }

a { color: var(--accent); text-decoration: none; border-bottom: 2px solid transparent; transition: border-color 0.1s ease; font-weight: 700; }
a:hover { border-bottom-color: var(--accent); }

/* --- Top Bar --- */
.topbar {
  position: sticky; top: 0; z-index: 100;
  display: flex; justify-content: space-between; align-items: center;
  padding: 1rem 2rem; background: var(--bg);
  border-bottom: 3px solid var(--border);
  flex-wrap: wrap; gap: 1rem;
}

.brand { display: flex; align-items: center; gap: 0.75rem; font-family: var(--sans); font-weight: 700; font-size: 1.2rem; text-transform: uppercase; }
.logo { display: inline-flex; align-items: center; justify-content: center; width: 36px; height: 36px; background: var(--accent); color: var(--bg); border: 2px solid var(--border); font-family: var(--mono); font-weight: 700; box-shadow: 4px 4px 0px var(--accent-2); }

.topbar-search { flex: 1; max-width: 400px; }
.topbar-search input {
  width: 100%; padding: 0.6rem 0.75rem; background: var(--card);
  border: 2px solid var(--border); color: var(--fg); font-family: var(--mono);
  font-size: 0.85rem; text-transform: uppercase; letter-spacing: 0.05em;
}
.topbar-search input:focus { outline: none; border-color: var(--accent); box-shadow: 4px 4px 0px var(--accent-2); }

.icon-btn {
  background: var(--card); border: 2px solid var(--border); color: var(--fg); height: 36px;
  padding: 0 1rem; cursor: pointer; display: flex; align-items: center; justify-content: center;
  font-family: var(--sans); font-weight: 700; font-size: 0.8rem; text-transform: uppercase;
  transition: all 0.1s; box-shadow: 3px 3px 0px var(--border);
}
.icon-btn:hover { background: var(--accent); color: var(--bg); transform: translate(2px, 2px); box-shadow: 1px 1px 0px var(--border); }

/* --- Hero --- */
.hero { position: relative; min-height: 80vh; display: flex; align-items: center; padding: 4rem 2rem; overflow: hidden; border-bottom: 3px solid var(--border); }
.hero-canvas { position: absolute; inset: 0; width: 100%; height: 100%; z-index: 0; opacity: 0.4; }
.hero-content { position: relative; z-index: 2; max-width: 1200px; width: 100%; margin: 0 auto; }
.kicker { text-transform: uppercase; letter-spacing: 0.2em; font-size: 0.8rem; color: var(--accent); margin-bottom: 1.5rem; display: inline-block; border: 1px solid var(--accent); padding: 0.25rem 0.75rem; }
.hero-title { font-size: clamp(3rem, 9vw, 7.5rem); margin-bottom: 2rem; }
.hero-title span { display: block; }
.title-em { color: var(--accent); }
.title-script { font-family: var(--mono); font-size: 0.4em; font-weight: 400; letter-spacing: 0; color: var(--muted); margin-top: 1rem; text-transform: lowercase; }
.hero-sub { max-width: 600px; font-size: 1.1rem; color: var(--fg); margin-bottom: 3rem; }
.hero-sub code { background: var(--card); border: 1px solid var(--border); padding: 0.1em 0.4em; color: var(--accent); }
.hero-meta { display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); gap: 1px; max-width: 800px; margin-bottom: 3rem; border: 2px solid var(--border); background: var(--border); }
.meta-cell { display: flex; flex-direction: column; background: var(--bg); padding: 1rem; }
.meta-num { font-family: var(--sans); font-size: 2.5rem; font-weight: 700; color: var(--accent); line-height: 1; }
.meta-label { font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.1em; color: var(--muted); margin-top: 0.5rem; }
.hero-cta { display: inline-flex; align-items: center; gap: 0.5rem; background: var(--accent); color: var(--bg); padding: 1rem 2rem; font-weight: 700; font-family: var(--sans); text-transform: uppercase; border: 2px solid var(--border); box-shadow: var(--shadow-offset) var(--shadow-offset) 0px var(--accent-2); transition: all 0.1s ease-in-out; }
.hero-cta:hover { transform: translate(var(--shadow-offset), var(--shadow-offset)); box-shadow: 0px 0px 0px var(--accent-2); }

/* --- Layout & Sidebar --- */
.layout { display: grid; grid-template-columns: 260px 1fr; max-width: 1400px; margin: 0 auto; }
.sidebar { position: sticky; top: 85px; height: calc(100vh - 85px); padding: 2rem 1.5rem; border-right: 3px solid var(--border); overflow-y: auto; }
.nav-title { text-transform: uppercase; letter-spacing: 0.15em; font-size: 0.7rem; color: var(--muted); margin-bottom: 1rem; }
.nav-list { list-style: none; padding: 0; margin: 0; display: flex; flex-direction: column; gap: 0; }
.nav-list a { display: block; padding: 0.6rem 0.75rem; border-left: 4px solid transparent; color: var(--fg); font-size: 0.85rem; border-bottom: none; transition: all 0.1s ease; margin-bottom: 2px; }
.nav-list a:hover { background: var(--card); border-left-color: var(--accent-2); color: var(--accent-2); }
.nav-list a.active { background: var(--card); color: var(--accent); border-left-color: var(--accent); font-weight: 700; }
.sidebar-progress { position: absolute; bottom: 0; left: 0; width: 100%; height: 4px; background: var(--card); }
.progress-bar { height: 100%; width: 0%; background: var(--accent); }

main { padding: 3rem 3rem 6rem; min-width: 0; }

/* --- Chapters & Specimens --- */
.chapter { margin-bottom: 5rem; }
.chapter hgroup { margin-bottom: 2rem; border-bottom: 3px solid var(--border); padding-bottom: 1rem; }
.chapter h2 { font-size: clamp(2rem, 5vw, 3rem); display: flex; align-items: center; gap: 1rem; flex-wrap: wrap; }
.ch-num { font-family: var(--mono); font-size: 1rem; font-weight: 700; color: var(--bg); background: var(--accent); padding: 0.25rem 0.75rem; border: 2px solid var(--border); box-shadow: 3px 3px 0px var(--accent-2); }
.ch-sub { font-size: 1.1rem; color: var(--muted); font-family: var(--sans); margin: 0; text-transform: none; letter-spacing: 0; }

.specimen-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 1.5rem; align-items: start; }
.specimen-grid .span-2 { grid-column: 1 / -1; }

.specimen { background: var(--card); border: 2px solid var(--border); padding: 1.5rem; display: flex; flex-direction: column; gap: 1rem; transition: transform 0.1s ease, box-shadow 0.1s ease; box-shadow: var(--shadow-offset) var(--shadow-offset) 0px var(--bg); }
.specimen:hover { border-color: var(--accent); transform: translate(-3px, -3px); box-shadow: 9px 9px 0px var(--accent-2); }
.specimen-head { display: flex; justify-content: space-between; align-items: center; border-bottom: 2px dashed var(--border); padding-bottom: 0.75rem; gap: 1rem; }
.tag { font-family: var(--mono); font-weight: 700; color: var(--accent); font-size: 1rem; }
.cat { font-size: 0.65rem; text-transform: uppercase; letter-spacing: 0.1em; color: var(--bg); background: var(--accent-2); padding: 0.25rem 0.5rem; font-weight: 700; }
.desc { font-size: 0.85rem; color: var(--muted); margin: 0; }

.demo { background: var(--bg); border: 1px solid var(--muted); padding: 1.5rem; font-size: 0.85rem; overflow-x: auto; }
.demo.prose { padding: 2rem; line-height: 1.7; }

/* --- Specific Element Styles --- */
.heading-demo h1, .heading-demo h2, .heading-demo h3, .heading-demo h4, .heading-demo h5, .heading-demo h6 { margin: 0.2rem 0; font-size: 1.1rem; }
.generic-box { border: 2px dashed var(--accent); padding: 1rem; color: var(--accent); }
pre { background: var(--bg); padding: 0; margin: 0; white-space: pre-wrap; word-break: break-all; color: var(--accent); }
code { color: var(--accent); }

blockquote { margin: 0; border-left: 4px solid var(--accent-2); padding-left: 1.5rem; font-style: normal; color: var(--fg); }
blockquote footer, blockquote cite { color: var(--muted); font-size: 0.8rem; font-style: normal; display: block; margin-top: 0.5rem; }
address { font-style: normal; color: var(--muted); }

/* Tables */
table { width: 100%; border-collapse: collapse; font-size: 0.85rem; min-width: 400px; }
caption { caption-side: bottom; text-align: left; color: var(--muted); padding: 0.5rem; font-size: 0.75rem; }
th, td { padding: 0.75rem; border: 2px solid var(--border); text-align: left; }
th { background: var(--card); font-weight: 700; color: var(--accent); text-transform: uppercase; }

/* Forms */
.demo-form { display: grid; gap: 1.5rem; }
fieldset { border: 2px solid var(--border); background: var(--card); padding: 1.5rem; }
legend { padding: 0.5rem 1rem; color: var(--bg); background: var(--accent); font-weight: 700; text-transform: uppercase; border: 2px solid var(--border); }

.form-row { display: flex; flex-direction: column; gap: 0.5rem; margin-bottom: 1.25rem; }
.form-row:last-child { margin-bottom: 0; }
.form-row label { color: var(--fg); font-size: 0.75rem; text-transform: uppercase; letter-spacing: 0.05em; font-weight: 700; }
.form-row-check, .form-row-btn { margin-bottom: 1.25rem; }
.form-row-check label { display: flex; align-items: center; gap: 0.5rem; color: var(--fg); cursor: pointer; text-transform: none; font-size: 0.9rem; }
.radio-group { padding: 0; border: none; display: flex; flex-direction: column; gap: 0.5rem; }
.radio-group legend { color: var(--fg); background: transparent; border: none; padding: 0; margin-bottom: 0.5rem; }
.radio-group label { display: flex; align-items: center; gap: 0.5rem; color: var(--fg); cursor: pointer; text-transform: none; font-size: 0.9rem; }

input[type="text"], input[type="email"], input[type="password"], input[type="url"],
input[type="tel"], input[type="search"], input[type="number"], input[type="date"],
input[type="time"], input[type="datetime-local"], input[type="month"], input[type="week"],
input[list], select, textarea {
  width: 100%; padding: 0.75rem; background: var(--bg); border: 2px solid var(--border);
  color: var(--fg); font-family: var(--mono); font-size: 0.9rem; transition: border-color 0.1s, box-shadow 0.1s;
}
input:focus, select:focus, textarea:focus { outline: none; border-color: var(--accent); box-shadow: 4px 4px 0px var(--accent-2); }
input[type="range"] { width: 100%; accent-color: var(--accent); padding: 0; background: transparent; border: none; }
input[type="color"] { width: 100%; height: 48px; padding: 0; border: 2px solid var(--border); background: var(--bg); cursor: pointer; }
input[type="file"] { padding: 0.5rem; border: 2px dashed var(--border); background: var(--bg); width: 100%; }
input[type="checkbox"], input[type="radio"] { accent-color: var(--accent); width: 18px; height: 18px; }

button, input[type="submit"], input[type="reset"], input[type="button"] {
  padding: 0.75rem 1.5rem; background: var(--card); border: 2px solid var(--border); color: var(--fg);
  font-family: var(--sans); font-size: 0.85rem; font-weight: 700; text-transform: uppercase;
  cursor: pointer; transition: all 0.1s; margin-right: 0.5rem; margin-bottom: 0.5rem;
  display: inline-flex; align-items: center; justify-content: center; box-shadow: 4px 4px 0px var(--border);
}
button:hover, input[type="submit"]:hover, input[type="reset"]:hover, input[type="button"]:hover { background: var(--accent); color: var(--bg); border-color: var(--border); transform: translate(2px, 2px); box-shadow: 2px 2px 0px var(--border); }
input[type="image"] { padding: 0; border: none; background: none; box-shadow: none; }
.cta-mini { background: var(--accent) !important; color: var(--bg) !important; }
.cta-mini:hover { background: var(--accent-2) !important; }

progress, meter { width: 100%; height: 20px; accent-color: var(--accent); border: 2px solid var(--border); }

/* Interactive Elements */
details { background: var(--bg); border: 2px solid var(--border); padding: 1rem; margin-bottom: 0.5rem; }
summary { cursor: pointer; font-weight: 700; color: var(--accent); text-transform: uppercase; }
details[open] summary { border-bottom: 2px dashed var(--border); padding-bottom: 0.5rem; margin-bottom: 0.5rem; }

dialog { background: var(--bg); border: 3px solid var(--accent); padding: 2rem; color: var(--fg); max-width: 400px; box-shadow: 15px 15px 0px var(--accent-2); top: 50%; left: 50%; transform: translate(-50%, -50%); }
dialog::backdrop { background: rgba(13, 13, 13, 0.85); backdrop-filter: blur(4px); }

/* Structure Diagram */
.structure-diagram { display: flex; flex-direction: column; gap: 0.5rem; border: 2px solid var(--border); padding: 1.5rem; margin-bottom: 2rem; background: var(--card); }
.struct-box { border: 2px solid var(--accent-2); padding: 1rem; text-align: center; color: var(--accent-2); font-family: var(--mono); font-size: 0.8rem; }
.struct-row { display: flex; gap: 0.5rem; }
.struct-aside { flex: 1; }
.struct-main { flex: 2; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 0.5rem; }
.struct-inner { border: 2px dashed var(--muted); padding: 0.5rem; width: 80%; color: var(--muted); }

/* SVG / Canvas / Math */
canvas { display: block; width: 100%; max-width: 100%; height: auto; border: 1px solid var(--border); background: var(--bg); }
#demo-canvas { height: 200px; }
.math-demo { display: flex; justify-content: center; align-items: center; padding: 2rem; overflow-x: auto; }
math { font-size: 1.5rem; color: var(--accent); }

/* Cloned Card (Template) */
.cloned-card { background: var(--bg); border: 2px solid var(--accent); padding: 1rem; margin-bottom: 0.5rem; }
.cloned-card p { margin: 0 0 0.25rem; color: var(--fg); }
.cloned-card small { color: var(--muted); }

/* --- CSS LAB --- */
.css-lab {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  border: 2px solid var(--border);
  background: var(--card);
  padding: 1.5rem;
  box-shadow: 6px 6px 0px var(--bg);
}
.lab-controls { display: flex; flex-direction: column; gap: 1rem; }
.lab-preview { 
  display: flex; 
  flex-direction: column; 
  border: 2px solid var(--border); 
  background: var(--bg); 
  min-height: 400px; 
}
#lab-iframe {
  width: 100%; 
  height: 500px; /* Explicitly set height to prevent collapse */
  border: none; 
  background: var(--bg);
  display: block;
}
.lab-controls textarea {
  resize: vertical; 
  min-height: 300px; 
  white-space: pre; 
  overflow-x: auto;
}

/* --- Footer --- */
.site-footer { border-top: 3px solid var(--border); padding: 4rem 3rem 2rem; background: var(--bg); }
.footer-cols { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 2rem; max-width: 1200px; margin: 0 auto 2rem; }
.footer-col h4 { color: var(--accent); font-size: 1.2rem; margin-bottom: 1rem; }
.footer-col p, .footer-col ul { color: var(--muted); font-size: 0.85rem; }
.footer-col ul { list-style: none; padding: 0; }
.footer-col li { margin-bottom: 0.5rem; }
.footer-bottom { text-align: center; padding-top: 2rem; border-top: 2px dashed var(--border); color: var(--muted); }

/* --- Responsive --- */
@media (max-width: 900px) {
  .layout { grid-template-columns: 1fr; }
  .sidebar { position: relative; top: 0; height: auto; border-right: none; border-bottom: 3px solid var(--border); overflow-x: auto; }
  .nav-list { flex-direction: row; flex-wrap: nowrap; gap: 1rem; }
  .nav-list a { border-left: none; border-bottom: 3px solid transparent; white-space: nowrap; }
  .nav-list a.active { border-left: none; border-bottom-color: var(--accent); }
  main { padding: 2rem 1.5rem 4rem; }
  .hero { min-height: auto; padding-top: 4rem; }
  .footer-cols { gap: 2rem; }
  .site-footer { padding: 2rem 1.5rem; }
  .css-lab { grid-template-columns: 1fr; }
}