/* ===== CSS Variables & Google Fonts ===== */
@import url('https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@400;700&family=Crimson+Pro:ital,wght@0,400;0,600;1,400&display=swap');

:root {
  --bg-primary: #0d1117;
  --bg-secondary: #161b22;
  --bg-card: #21262d;
  --accent: #58a6ff;
  --accent-hover: #79c0ff;
  --text-primary: #e6edf3;
  --text-secondary: #8b949e;
  --border: #30363d;
  --success: #3fb950;
  --warning: #d29922;
  --fallback-color: var(--accent, #58a6ff);
}

/* ===== Universal Selector ===== */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

/* ===== Element Selector ===== */
body {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: 'Crimson Pro', Georgia, serif;
  font-size: 1.1rem;
  line-height: 1.7;
  min-width: 320px;
}

/* ===== Header ===== */
header {
  background-color: var(--bg-secondary);
  border-bottom: 2px solid var(--border);
  padding-top: 2rem;
  padding-right: 2rem;
  padding-bottom: 1rem;
  padding-left: 2rem;
  position: sticky;
  top: 0px;
  z-index: 100;
}

header h1 {
  font-family: 'JetBrains Mono', monospace;
  color: var(--accent);
  font-size: 1.8rem;
  margin-bottom: 0.3rem;
}

header h2 {
  color: var(--text-secondary);
  font-size: 1rem;
  font-weight: 400;
}

header h3 {
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-family: 'JetBrains Mono', monospace;
}

/* ===== Nav ===== */
nav {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  align-items: center;
  margin-top: 1rem;
  margin-bottom: 0.5rem;
}

nav a {
  color: var(--accent);
  text-decoration: none;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.85rem;
  padding: 4px 10px;
  border-radius: 20px;
  border: 1px solid var(--border);
  transition: all 0.2s;
}

/* ===== Pseudo-class: hover & active ===== */
nav a:hover {
  background-color: var(--accent);
  color: var(--bg-primary);
}

nav a:active {
  background-color: var(--accent-hover);
}

hr {
  border: none;
  border-top: 1px solid var(--border);
  margin-top: 1rem;
}

/* ===== Main Layout ===== */
main {
  max-width: 860px;
  min-width: 280px;
  width: 90%;
  margin: 2rem auto;
}

/* ===== Section Cards ===== */
section {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 8px;
  margin-bottom: 1.5rem;
  padding: 1.5rem;
}

/* ===== Descendant Combinator ===== */
section h2 {
  font-family: 'JetBrains Mono', monospace;
  color: var(--accent);
  font-size: 1.1rem;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border);
}

/* ===== Child Combinator ===== */
section > p {
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

/* ===== ID Selector ===== */
#attendance {
  border-left: 4px solid var(--success);
}

#agenda {
  border-left: 4px solid var(--accent);
}

#form {
  border-left: 4px solid var(--warning);
}

/* ===== Lists ===== */
ul, ol {
  padding-left: 1.5rem;
}

ul li, ol li {
  margin-bottom: 0.3rem;
  color: var(--text-primary);
}

/* ===== General Sibling Combinator ===== */
h2 ~ p {
  color: var(--text-secondary);
}

/* ===== Adjacent Sibling Combinator ===== */
p + p {
  margin-top: 0.5rem;
}

/* ===== Flexbox: Media Section ===== */
#media {
  display: flex;
  flex-direction: column;
  gap: 1.2rem;
  align-items: flex-start;
}

#media p {
  color: var(--text-secondary);
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.85rem;
}

/* ===== Attribute Selector ===== */
img[width] {
  border-radius: 8px;
  border: 2px solid var(--border);
  max-width: 100%;
  height: auto;
  display: block;
}

audio[controls], video[controls] {
  width: 100%;
  max-width: 400px;
}

/* ===== Grid: Form Layout ===== */
#form form {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.5rem;
}

fieldset {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.5rem;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  align-items: start;
}

legend {
  color: var(--accent);
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.9rem;
  padding: 0 0.5rem;
  grid-column: 1 / -1;
}

/* ===== Combining Two Selectors ===== */
fieldset p {
  grid-column: 1 / -1;
  margin: 0;
}

label {
  color: var(--text-secondary);
  font-size: 0.95rem;
  display: block;
  margin-bottom: 4px;
}

/* ===== Input Styling ===== */
input[type="text"],
input[type="date"],
textarea,
select {
  background-color: var(--bg-primary);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text-primary);
  padding: 8px 12px;
  width: 100%;
  font-family: 'Crimson Pro', serif;
  font-size: 1rem;
}

input[type="text"]:hover,
input[type="date"]:hover,
textarea:hover,
select:hover {
  border-color: var(--accent);
}

/* ===== Button ===== */
button[type="submit"] {
  background-color: var(--accent);
  color: var(--bg-primary);
  border: none;
  border-radius: 6px;
  padding: 10px 24px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.95rem;
  cursor: pointer;
  display: inline-block;
  grid-column: 1 / -1;
  width: fit-content;
}

button[type="submit"]:hover {
  background-color: var(--accent-hover);
}

button[type="submit"]:active {
  background-color: var(--success);
}

/* ===== Details / Summary ===== */
details {
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.8rem 1rem;
  margin-top: 0.8rem;
  background-color: var(--bg-secondary);
}

summary {
  color: var(--accent);
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.9rem;
  cursor: pointer;
}

details p {
  margin-top: 0.5rem;
  color: var(--text-secondary);
}

/* ===== Span ===== */
span {
  color: var(--warning);
  font-style: italic;
}

/* ===== Footer ===== */
footer {
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border);
  padding: 1.5rem 2rem;
  text-align: center;
}

footer p {
  color: var(--text-secondary);
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.85rem;
}

/* ===== :has() Selector ===== */
section:has(form) {
  border-color: var(--warning);
}

/* ===== Nested Selectors ===== */
nav {
  & a {
    letter-spacing: 0.03em;
  }
}

/* ===== Class Selector ===== */
.highlight {
  color: var(--accent);
  font-weight: 600;
}

/* ===== Selector List ===== */
h1, h2, h3 {
  line-height: 1.3;
}

/* ===== Wide-gamut Color ===== */
#new {
  border-left: 4px solid color(display-p3 0.2 0.6 1);
}

/* ===== color-mix ===== */
#misc {
  border-left: 4px solid color-mix(in srgb, var(--accent) 60%, var(--success) 40%);
}

/* ===== Display values ===== */
nav a {
  display: inline-block;
}

footer hr {
  display: none;
}

/* ===== Position ===== */
/* sticky already used in header */
/* relative used here */
section {
  position: relative;
}

/* ===== Box Model - absolute units ===== */
/* px, pt used in various places above */
body {
  margin: 0px;
  padding: 0pt;
}

/* ===== Media Query ===== */
@media (max-width: 600px) {
  header {
    position: static;
    padding: 1rem;
  }

  header h1 {
    font-size: 1.3rem;
  }

  nav {
    gap: 0.5rem;
  }

  nav a {
    font-size: 0.75rem;
    padding: 3px 8px;
  }

  fieldset {
    grid-template-columns: 1fr;
  }

  main {
    width: 95%;
    margin: 1rem auto;
  }
}

@media (min-width: 601px) and (max-width: 1024px) {
  main {
    width: 85%;
  }
}