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

:root {
  --bg: #f7f8fc;
  --surface: #ffffff;
  --primary: #3b6fd4;
  --primary-dark: #2a55b0;
  --text: #1e2330;
  --muted: #6b7280;
  --border: #e2e6f0;
  --radius: 10px;
}

body {
  font-family: 'Segoe UI', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.container {
  max-width: 860px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Header */
header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 10;
}

header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--primary);
  text-decoration: none;
}

nav a {
  color: var(--muted);
  text-decoration: none;
  margin-left: 1.5rem;
  font-size: 0.95rem;
  transition: color 0.2s;
}

nav a:hover { color: var(--primary); }

/* Main */
main {
  flex: 1;
  padding: 3rem 1.5rem;
}

/* Hero */
.hero {
  text-align: center;
  padding: 4rem 0 3rem;
}

.hero h1 {
  font-size: 2.4rem;
  margin-bottom: 0.75rem;
}

.hero p {
  color: var(--muted);
  font-size: 1.1rem;
  margin-bottom: 1.5rem;
}

/* Buttons */
.btn {
  display: inline-block;
  background: var(--primary);
  color: #fff;
  padding: 0.6rem 1.4rem;
  border-radius: var(--radius);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  transition: background 0.2s;
}

.btn:hover { background: var(--primary-dark); }

.btn.outline {
  background: transparent;
  color: var(--primary);
  border: 2px solid var(--primary);
  margin-top: 1rem;
}

.btn.outline:hover {
  background: var(--primary);
  color: #fff;
}

/* Recent posts */
.recent h2 {
  font-size: 1.5rem;
  margin-bottom: 1.5rem;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 1.25rem;
  margin-bottom: 1.5rem;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  text-decoration: none;
  color: var(--text);
  transition: box-shadow 0.2s, transform 0.2s;
}

.card:hover {
  box-shadow: 0 4px 16px rgba(59,111,212,0.12);
  transform: translateY(-2px);
}

.card h3 { font-size: 1rem; margin-bottom: 0.3rem; }
.card time { font-size: 0.8rem; color: var(--muted); display: block; margin-bottom: 0.6rem; }
.card p { font-size: 0.9rem; color: var(--muted); }

/* Blog list */
h1 { font-size: 2rem; margin-bottom: 2rem; }

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

.post-summary {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
}

.post-summary a { text-decoration: none; color: var(--text); }
.post-summary h2 { font-size: 1.3rem; margin-bottom: 0.3rem; transition: color 0.2s; }
.post-summary a:hover h2 { color: var(--primary); }
.post-summary time { font-size: 0.82rem; color: var(--muted); display: block; margin-bottom: 0.75rem; }
.post-summary p { color: var(--muted); margin-bottom: 0.75rem; }

.read-more { color: var(--primary); text-decoration: none; font-size: 0.9rem; font-weight: 600; }
.read-more:hover { text-decoration: underline; }

/* Single post */
.post { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 2.5rem; }

.post-header { margin-bottom: 2rem; border-bottom: 1px solid var(--border); padding-bottom: 1.25rem; }
.post-header h1 { font-size: 1.9rem; margin-bottom: 0.4rem; }
.post-header time { color: var(--muted); font-size: 0.85rem; }

.post-body { font-size: 1.05rem; line-height: 1.85; color: #2d3340; margin-bottom: 2rem; white-space: pre-wrap; }

/* Footer login link */
footer .container { position: relative; }
.footer-login { position: absolute; right: 0; top: 50%; transform: translateY(-50%); font-size: 0.75rem; color: var(--border); text-decoration: none; }
.footer-login:hover { color: var(--muted); }

/* Auth */
.auth-box { max-width: 380px; margin: 3rem auto; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 2rem; }
.auth-box h1 { margin-bottom: 1.5rem; font-size: 1.5rem; }
.auth-box label { display: block; font-size: 0.9rem; font-weight: 600; margin-bottom: 0.3rem; }
.auth-box input { width: 100%; padding: 0.55rem 0.75rem; border: 1px solid var(--border); border-radius: 6px; font-size: 1rem; margin-bottom: 1rem; }
.auth-box button { width: 100%; padding: 0.65rem; background: var(--primary); color: #fff; border: none; border-radius: 6px; font-size: 1rem; font-weight: 600; cursor: pointer; }
.auth-box button:hover { background: var(--primary-dark); }
.auth-error { color: #c0392b; background: #fdecea; border: 1px solid #f5c6cb; border-radius: 6px; padding: 0.6rem 0.9rem; margin-bottom: 1rem; font-size: 0.9rem; }

/* Footer */
footer {
  background: var(--surface);
  border-top: 1px solid var(--border);
  padding: 1.25rem 0;
  text-align: center;
  font-size: 0.85rem;
  color: var(--muted);
}