@import url('https://fonts.googleapis.com/css2?family=Space+Mono:wght@400;700&family=IBM+Plex+Sans:wght@300;400;500;600;700&display=swap');

:root {
  --font-display: 'Space Mono', monospace;
  --font-body: 'IBM Plex Sans', sans-serif;
  --bg: #0a0a0a;
  --bg-card: #141414;
  --bg-hover: #1a1a1a;
  --text: #e8e8e8;
  --text-muted: #888;
  --border: #222;
  --radius: 6px;
  --accent: #EC4899;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.site-header {
  border-bottom: 1px solid var(--border);
  padding: 1rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  background: rgba(10,10,10,0.95);
  backdrop-filter: blur(10px);
  z-index: 100;
}

.site-logo {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--accent);
}

.site-nav { display: flex; gap: 1.5rem; align-items: center; }
.site-nav a { color: var(--text-muted); font-size: 0.9rem; font-weight: 500; }
.site-nav a:hover { color: var(--text); text-decoration: none; }

main { flex: 1; max-width: 1100px; width: 100%; margin: 0 auto; padding: 2rem; }

h1, h2, h3 { font-family: var(--font-display); }
h1 { font-size: 2rem; margin-bottom: 0.5rem; }
h2 { font-size: 1.4rem; margin-bottom: 0.75rem; }
h3 { font-size: 1.1rem; margin-bottom: 0.5rem; }

.hero { text-align: center; padding: 3rem 0 2rem; }
.hero p { color: var(--text-muted); font-size: 1.1rem; max-width: 600px; margin: 0.5rem auto 0; }

/* Controls */
.controls {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  margin-bottom: 1.5rem;
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  align-items: flex-end;
}

.control-group { display: flex; flex-direction: column; gap: 0.3rem; }

label {
  display: block;
  font-size: 0.8rem;
  color: var(--text-muted);
  font-weight: 500;
}

select, input[type="number"] {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  padding: 0.5rem 0.7rem;
  font-family: var(--font-display);
  font-size: 0.85rem;
  outline: none;
}

select:focus, input:focus { border-color: var(--accent); }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background: var(--accent);
  color: #000;
  border: none;
  border-radius: var(--radius);
  padding: 0.5rem 1rem;
  font-family: var(--font-body);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: opacity 0.2s;
}

.btn:hover { opacity: 0.85; }
.btn-outline { background: transparent; border: 1px solid var(--border); color: var(--text); }
.btn-outline:hover { border-color: var(--accent); color: var(--accent); }
.btn-sm { padding: 0.35rem 0.7rem; font-size: 0.8rem; }

/* Matrix input */
.matrix-area {
  display: flex;
  flex-wrap: wrap;
  gap: 2rem;
  margin-bottom: 1.5rem;
  align-items: flex-start;
}

.matrix-panel {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  flex: 1;
  min-width: 280px;
}

.matrix-panel h3 { color: var(--accent); margin-bottom: 0.75rem; font-size: 0.95rem; }

.matrix-grid {
  display: inline-grid;
  gap: 4px;
  margin-bottom: 0.75rem;
}

.matrix-grid input {
  width: 60px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 3px;
  color: var(--text);
  padding: 0.4rem;
  font-family: var(--font-display);
  font-size: 0.85rem;
  text-align: center;
  outline: none;
}

.matrix-grid input:focus { border-color: var(--accent); }

.matrix-actions { display: flex; gap: 0.5rem; flex-wrap: wrap; }

/* Operation selector */
.op-selector {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

.op-btn {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text-muted);
  padding: 0.5rem 0.9rem;
  font-family: var(--font-body);
  font-size: 0.85rem;
  cursor: pointer;
  transition: border-color 0.2s, color 0.2s;
}

.op-btn:hover { border-color: var(--accent); color: var(--text); }
.op-btn.active { border-color: var(--accent); color: var(--accent); background: rgba(236,72,153,0.1); }

/* Result */
.result-area {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  min-height: 80px;
}

.result-area h3 { color: var(--accent); margin-bottom: 1rem; }

.result-matrix {
  display: inline-grid;
  gap: 2px;
  background: var(--border);
  border: 2px solid var(--accent);
  border-radius: 4px;
  padding: 2px;
}

.result-cell {
  background: var(--bg);
  padding: 0.4rem 0.6rem;
  font-family: var(--font-display);
  font-size: 0.85rem;
  text-align: center;
  min-width: 55px;
}

.scalar-result {
  font-family: var(--font-display);
  font-size: 1.3rem;
  color: var(--accent);
  padding: 0.5rem 0;
}

/* Steps */
.steps {
  margin-top: 1.5rem;
  border-top: 1px solid var(--border);
  padding-top: 1rem;
}

.steps h4 { color: var(--text-muted); font-size: 0.85rem; margin-bottom: 0.75rem; font-family: var(--font-display); }

.step {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.75rem;
  margin-bottom: 0.5rem;
  font-size: 0.85rem;
  line-height: 1.5;
}

.step-label { color: var(--accent); font-weight: 600; margin-bottom: 0.25rem; }
.step .formula { font-family: var(--font-display); font-size: 0.8rem; }

.subscript { font-size: 0.65em; vertical-align: sub; }
.superscript { font-size: 0.65em; vertical-align: super; }

/* History */
.history-area {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  margin-bottom: 1.5rem;
}

.history-area h3 { color: var(--accent); margin-bottom: 0.75rem; font-size: 0.95rem; }

.history-item {
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.8rem;
  color: var(--text-muted);
  font-family: var(--font-display);
  cursor: pointer;
}

.history-item:hover { color: var(--text); }
.history-item:last-child { border-bottom: none; }

.error-msg { color: #ef4444; font-weight: 500; }

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 2rem;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
}

.site-footer a { color: var(--text-muted); }
.site-footer a:hover { color: var(--accent); }
.footer-links { display: flex; justify-content: center; gap: 1.5rem; margin-bottom: 0.75rem; flex-wrap: wrap; }

/* Blog */
.blog-list { list-style: none; }
.blog-list li { border-bottom: 1px solid var(--border); padding: 1.25rem 0; }
.blog-list li:last-child { border-bottom: none; }
.blog-list a { font-size: 1.1rem; font-weight: 600; }
.blog-meta { color: var(--text-muted); font-size: 0.8rem; margin-top: 0.25rem; }
.blog-excerpt { color: var(--text-muted); font-size: 0.9rem; margin-top: 0.35rem; }

.article-content { max-width: 720px; margin: 0 auto; }
.article-content h1 { font-size: 1.8rem; margin-bottom: 0.5rem; }
.article-content .blog-meta { margin-bottom: 2rem; }
.article-content p { margin-bottom: 1rem; }
.article-content h2 { margin-top: 2rem; }
.article-content h3 { margin-top: 1.5rem; }
.article-content ul, .article-content ol { margin-bottom: 1rem; padding-left: 1.5rem; }
.article-content li { margin-bottom: 0.35rem; }
.article-content pre {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem;
  overflow-x: auto;
  margin-bottom: 1rem;
  font-family: var(--font-display);
  font-size: 0.85rem;
}
.article-content code {
  font-family: var(--font-display);
  font-size: 0.85rem;
  background: var(--bg-card);
  padding: 0.15rem 0.35rem;
  border-radius: 3px;
}
.article-content pre code { background: none; padding: 0; }

@media (max-width: 700px) {
  .site-header { padding: 0.75rem 1rem; }
  main { padding: 1rem; }
  .hero { padding: 2rem 0 1rem; }
  h1 { font-size: 1.5rem; }
  .matrix-area { flex-direction: column; }
  .controls { flex-direction: column; }
  .matrix-grid input { width: 50px; }
}