/* RBD digital theme */

:root {
  --color-bg: #0B1C38;           /* primary background colour */
  --color-bg-alt: #101528;       /* slightly lighter navy for sections */
  --color-accent: #1e9bff;       /* electric blue highlight */
  --color-accent-light: #63c6ff; /* glow blue */
  --color-gold: #ffd700;         /* gold accent for math + details */
  --color-text: #e8ebf0;         /* soft white */
  --color-secondary: #7EB7F4;    /* secondary header color */
  --color-subtle: #A9CBF0;       /* secondary muted text */
  --font-display: 'Press Start 2P', monospace; /* pixel-art style */
  --font-body: 'Inter', 'Segoe UI', sans-serif;
}

body {
  font-family: var(--font-body);
  background: var(--color-bg);
  color: var(--color-text);
  margin: 0;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

header {
  text-align: center;
  padding-top: 2rem;
  background: linear-gradient(180deg, var(--color-bg-alt), var(--color-bg));
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

header img.logo {
  width: 240px;
  height: auto;
  display: block;
  margin: 0 auto 1.5rem;
  border-radius: 12px;
  box-shadow: 0 0 35px rgba(30, 155, 255, 0.25);
}

header h1 {
  font-family: var(--font-display);
  font-size: 1.2rem;
  letter-spacing: 2px;
  color: var(--color-accent-light);
  text-shadow: 0 0 10px var(--color-accent);
  margin: 0;
}

header h4 {
    color: var(--color-secondary);
    margin: 0.3rem;
}

header .spacer {
  padding: 1rem;
}

main {
  max-width: 860px;
  margin: 2rem auto;
  padding: 2rem;
  background: var(--color-bg-alt);
  border-radius: 12px;
  box-shadow: 0 0 35px rgba(0, 0, 0, 0.4);
}

.post h1, .post h2, .post h3 {
  color: var(--color-accent-light);
  font-weight: 600;
}

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: all 0.2s ease;
}

a:hover {
  color: var(--color-accent-light);
  text-shadow: 0 0 8px var(--color-accent-light);
}

code {
  background: #111830;
  color: var(--color-accent-light);
  padding: 0.2em 0.4em;
  border-radius: 4px;
  font-family: 'Source Code Pro', monospace;
  font-size: 0.9em;
}

pre code {
  display: block;
  overflow-x: auto;
  padding: 1rem;
  border-radius: 8px;
  background: #0d1228;
}

footer {
  text-align: center;
  color: var(--color-subtle);
  font-size: 0.8rem;
  padding: 2rem;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  margin-top: 3rem;
  letter-spacing: 0.3px;
}

footer p {
  margin: 0.3rem 0;
}

.post-list {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.post h2 a {
  color: var(--color-accent-light);
  font-family: var(--font-display);
  font-size: 1rem;
  text-shadow: 0 0 6px rgba(30, 155, 255, 0.4);
}

.post h2 a:hover {
  color: var(--color-accent);
}

.post-meta {
  color: var(--color-subtle);
  font-size: 0.85rem;
  margin-top: -0.5rem;
  margin-bottom: 1rem;
}

.summary {
  color: var(--color-text);
  font-size: 1rem;
  line-height: 1.7;
}

/* === KaTeX custom theme for RBD Digital === */
.katex {
  font-size: 1.05rem;
  color: #fdf6e3;
}

.katex-display {
  margin: 1.5em 0;
  text-align: center;
}

.katex .mord,
.katex .mop,
.katex .mbin,
.katex .mrel,
.katex .mord.text {
  color: #fdf6e3;
}

.katex .mord.mathit,
.katex .mord.operatorname,
.katex .mord.greek,
.katex .mop {
  color: var(--color-gold);
}

.katex .frac-line {
  border-color: var(--color-gold);
}

.katex .sqrt-line {
  border-top-color: var(--color-gold);
}

.katex .delimcenter {
  color: #fdf6e3;
}

.katex .msupsub {
  color: var(--color-gold);
}

.katex-error {
  color: #ff5555;
  background-color: rgba(255, 0, 0, 0.15);
  padding: 0.2em 0.4em;
  border-radius: 4px;
}

/* === Utility classes === */
.center {
  text-align: center;
}

hr {
  border: none;
  height: 1px;
  background: rgba(255, 255, 255, 0.05);
  margin: 2rem 0;
}