/* ========================================
   ratopi.dev – minimal cool stylesheet
   ======================================== */

:root {
  --color-bg: #1a1b26;
  --color-surface: #222336;
  --color-text: #c0caf5;
  --color-text-muted: #737aa2;
  --color-accent: #7aa2f7;
  --color-accent-hover: #89b4fa;
  --color-accent-dim: #3d59a1;
  --color-border: #2e3150;
  --color-code-bg: #16161e;
  --color-hero-bg: linear-gradient(135deg, #1a1b26 0%, #24283b 50%, #1a1b26 100%);
  --font-body: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-mono: ui-monospace, 'SF Mono', SFMono-Regular, Menlo, Consolas, 'Liberation Mono', monospace;
  --max-width: 720px;
  --nav-height: 60px;
}

/* --- Reset --- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.7;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

/* --- Container --- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* --- Navigation --- */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(26, 27, 38, 0.85);
  backdrop-filter: blur(16px) saturate(1.5);
  -webkit-backdrop-filter: blur(16px) saturate(1.5);
  border-bottom: 1px solid var(--color-border);
  height: var(--nav-height);
  display: flex;
  align-items: center;
}

.site-nav .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
}

.nav-brand {
  font-weight: 800;
  font-size: 1.1rem;
  color: var(--color-text);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.nav-brand:hover { color: var(--color-accent); }

.nav-links { display: flex; gap: 1.8rem; }

.nav-links a {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color 0.2s;
  letter-spacing: 0.01em;
}

.nav-links a:hover { color: var(--color-accent); }

.nav-feed {
  display: inline-flex;
  align-items: center;
}

.nav-feed svg {
  opacity: 0.5;
  transition: opacity 0.2s, color 0.2s;
}

.nav-feed:hover svg {
  opacity: 1;
}

/* --- Hero (Home page) --- */
.hero {
  background: var(--color-hero-bg);
  color: var(--color-text);
  padding: 6rem 1.5rem 5rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: 50%;
  transform: translateX(-50%);
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(122, 162, 247, 0.12) 0%, transparent 70%);
  pointer-events: none;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 0.5rem;
}

.hero .subtitle {
  font-size: 1.15rem;
  font-weight: 300;
  opacity: 0.85;
  max-width: 500px;
  margin: 0 auto 2rem;
}

.hero blockquote {
  font-style: italic;
  font-size: 1.05rem;
  opacity: 0.75;
  border: none;
  padding: 0;
  margin: 2rem auto 0;
  max-width: 480px;
}

.hero blockquote cite,
.hero blockquote small {
  display: block;
  font-style: normal;
  font-size: 0.85rem;
  margin-top: 0.4rem;
  opacity: 0.6;
}

/* --- Page Header --- */
.page-header {
  padding: 3rem 0 2rem;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 2.5rem;
}

.page-header h1 {
  font-size: clamp(1.8rem, 4vw, 2.5rem);
  font-weight: 800;
  letter-spacing: -0.03em;
}

.page-header .lead {
  font-size: 1.1rem;
  color: var(--color-text-muted);
  margin-top: 0.5rem;
  font-weight: 300;
}

/* --- Page Content --- */
.page-content {
  padding-bottom: 4rem;
}

.page-content h1,
.page-content h2,
.page-content h3,
.page-content h4 {
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-top: 2.5rem;
  margin-bottom: 0.8rem;
}

.page-content h1 { font-size: 1.8rem; }
.page-content h2 { font-size: 1.5rem; }
.page-content h3 { font-size: 1.25rem; }

.page-content p { margin-bottom: 1.2rem; }

.page-content a {
  color: var(--color-accent);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
  transition: color 0.2s;
}

.page-content a:hover { color: var(--color-accent-hover); }

.page-content ul,
.page-content ol {
  padding-left: 1.4rem;
  margin-bottom: 1.2rem;
}

.page-content li { margin-bottom: 0.4rem; }

.page-content blockquote {
  border-left: 3px solid var(--color-accent-dim);
  padding: 0.8rem 1.2rem;
  margin: 1.5rem 0;
  color: var(--color-text-muted);
  font-style: italic;
  background: var(--color-surface);
  border-radius: 0 6px 6px 0;
}

.page-content blockquote small {
  display: block;
  font-style: normal;
  font-size: 0.85rem;
  margin-top: 0.3rem;
  opacity: 0.7;
}

.page-content img {
  max-width: 100%;
  border-radius: 8px;
  margin: 1.5rem 0;
}

/* --- Code --- */
.page-content code,
.post-content code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background: var(--color-code-bg);
  padding: 0.15em 0.4em;
  border-radius: 4px;
}

.page-content pre,
.post-content pre {
  background: var(--color-code-bg);
  color: #a9b1d6;
  padding: 1.2rem 1.4rem;
  border-radius: 8px;
  border: 1px solid var(--color-border);
  overflow-x: auto;
  margin: 1.5rem 0;
  font-size: 0.9rem;
  line-height: 1.6;
}

.page-content pre code,
.post-content pre code {
  background: none;
  padding: 0;
  color: inherit;
}

/* --- Blog Post List --- */
.post-list {
  list-style: none;
  padding: 0;
}

.post-list-item {
  padding: 1.5rem 1rem;
  border-bottom: 1px solid var(--color-border);
  border-radius: 8px;
  transition: background 0.2s;
}

.post-list-item:hover {
  background: var(--color-surface);
}

.post-list-item:last-child { border-bottom: none; }

.post-list-item a {
  text-decoration: none;
  color: inherit;
  display: block;
}

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

.post-list-item h2 {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 0.3rem;
  transition: color 0.2s;
  letter-spacing: -0.01em;
}

.post-list-item .post-abstract {
  color: var(--color-text-muted);
  font-size: 0.95rem;
  margin-bottom: 0.3rem;
}

.post-list-item .post-meta {
  font-size: 0.82rem;
  color: var(--color-text-muted);
  opacity: 0.7;
}

/* --- Blog Post (single) --- */
.post-header {
  padding: 3rem 0 2rem;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 2.5rem;
}

.post-header h1 {
  font-size: clamp(1.8rem, 4vw, 2.4rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 0.5rem;
}

.post-header .post-abstract {
  font-size: 1.1rem;
  color: var(--color-text-muted);
  font-weight: 300;
  margin-bottom: 0.4rem;
}

.post-header .post-meta {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  opacity: 0.7;
}

.post-content {
  padding-bottom: 4rem;
}

/* Reuse page-content styles for post-content */
.post-content h1,
.post-content h2,
.post-content h3,
.post-content h4 {
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-top: 2.5rem;
  margin-bottom: 0.8rem;
}

.post-content h1 { font-size: 1.8rem; }
.post-content h2 { font-size: 1.5rem; }
.post-content h3 { font-size: 1.25rem; }

.post-content p { margin-bottom: 1.2rem; }

.post-content a {
  color: var(--color-accent);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
  transition: color 0.2s;
}

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

.post-content ul,
.post-content ol {
  padding-left: 1.4rem;
  margin-bottom: 1.2rem;
}

.post-content li { margin-bottom: 0.4rem; }

.post-content blockquote {
  border-left: 3px solid var(--color-accent-dim);
  padding: 0.8rem 1.2rem;
  margin: 1.5rem 0;
  color: var(--color-text-muted);
  font-style: italic;
  background: var(--color-surface);
  border-radius: 0 6px 6px 0;
}

.post-content img {
  max-width: 100%;
  border-radius: 8px;
  margin: 1.5rem 0;
}

/* --- Footer --- */
.site-footer {
  border-top: 1px solid var(--color-border);
  padding: 2.5rem 0;
  text-align: center;
  margin-top: 2rem;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 2rem;
  margin-bottom: 1rem;
}

.footer-links a {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.2s;
}

.footer-links a:hover { color: var(--color-accent); }

.copyright {
  font-size: 0.8rem;
  color: var(--color-text-muted);
  opacity: 0.6;
}

/* --- 404 --- */
.page-404 {
  text-align: center;
  padding: 6rem 1.5rem;
}

.page-404 h1 {
  font-size: 5rem;
  font-weight: 800;
  color: var(--color-accent-dim);
  margin-bottom: 0.5rem;
}

/* --- Selected Writings --- */
.selected-writings {
  padding: 3rem 1.5rem 2rem;
}

.selected-writings h2 {
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-text-muted);
  margin-bottom: 1.2rem;
}

.selected-writings ul {
  list-style: none;
  padding: 0;
}

.selected-writings li {
  margin-bottom: 0.8rem;
}

.selected-writings a {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-text);
  text-decoration: none;
  transition: color 0.2s;
}

.selected-writings a:hover {
  color: var(--color-accent);
}

/* --- Responsive --- */
@media (max-width: 600px) {
  body { font-size: 16px; }

  .nav-links { gap: 1.2rem; }
  .nav-links a { font-size: 0.85rem; }
  .nav-brand { font-size: 1rem; }

  .hero { padding: 4rem 1.2rem 3rem; }
  .page-header { padding: 2rem 0 1.5rem; }
  .post-header { padding: 2rem 0 1.5rem; }
}

/* --- Selection color --- */
::selection {
  background: var(--color-accent);
  color: #fff;
}

/* --- Smooth transitions --- */
a { transition: color 0.2s ease; }

/* --- Horizontal rule --- */
hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 2rem 0;
}

/* --- Notice box --- */
.notice {
  background: rgba(192, 168, 128, 0.06);
  border: 1px solid rgba(192, 168, 128, 0.25);
  border-left: 3px solid rgba(192, 168, 128, 0.5);
  padding: 1rem 1.5rem;
  margin: 0 2rem 2rem;
  border-radius: 6px;
  color: #b0a080;
  font-size: 0.95rem;
  line-height: 1.6;
}