/* theme variables: default = light, overridden by body.dark */

:root {
  --bg-color: #ffffff;
  --text-color: #1a202c;
  --secondary-text: #4b5563;
  --card-bg: #f3f4f6;
  --border-color: #d1d5db;
  --link-color: #2563eb;

  --button-bg: var(--link-color);
  --button-text: #ffffff;
  --button-border: transparent;
  --button-hover: rgba(0,0,0,0.06);
}

/* dark theme override */
body.dark {
  --bg-color: #0b1220;
  --text-color: #e6eef8;
  --secondary-text: #9ca3af;
  --card-bg: #111827;
  --border-color: #374151;
  --link-color: #60a5fa;

  --button-bg: #2563eb;
  --button-text: #ffffff;
  --button-border: transparent;
  --button-hover: rgba(255,255,255,0.04);
}

/* base */
body {
  margin: 0;
  font-family: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, Arial;
  background-color: var(--bg-color);
  color: var(--text-color);
  line-height: 1.6;
  transition: background-color 0.25s ease, color 0.25s ease;
}

/* layout */
.container { max-width: 900px; margin: 0 auto; padding: 1.5rem; }
.header { display: flex; gap: 1rem; align-items: center; justify-content: space-between; flex-wrap: wrap; }
.info h1 { margin: 0; font-size: 1.9rem; font-weight: 800; }
.info p { margin: 0.25rem 0 0; color: var(--secondary-text); }

/* actions */
.actions { display: flex; gap: 0.8rem; align-items: center; }

/* buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.45rem 0.9rem;
  border-radius: 10px;
  background: transparent;
  color: var(--text-color);
  border: 1px solid var(--border-color);
  cursor: pointer;
  font-weight: 600;
  transition: background 0.18s ease, transform 0.06s ease;
  text-decoration: none;
}
.btn:active { transform: translateY(1px); }
.btn:focus-visible { outline: 3px solid rgba(99,102,241,0.3); outline-offset: 2px; }
.btn:focus { outline: none; }

/* primary button */
.btn.primary {
  background: var(--button-bg);
  color: var(--button-text);
  border: 1px solid var(--button-border);
}
.btn.primary:hover { filter: brightness(0.95); }

/* content */
.content h2 { margin-top: 1.8rem; margin-bottom: 0.8rem; font-size: 1.4rem; font-weight: 700; }
.tags { display: flex; flex-wrap: wrap; gap: 0.5rem; }
.tags span {
  padding: 0.28rem 0.8rem;
  background: var(--card-bg);
  color: var(--text-color);
  border-radius: 999px;
  font-size: 0.92rem;
  border: 1px solid var(--border-color);
}

/* timeline */
.timeline { margin-top: 0.8rem; padding-left: 1rem; border-left: 2px solid var(--border-color); }
.timeline h3 { margin: 0.15rem 0; }
.timeline .period { color: var(--secondary-text); font-size: 0.88rem; }
.timeline ul { margin: 0.5rem 0 1.2rem; padding-left: 1.1rem; }

/* links */
a { color: var(--link-color); text-decoration: none; }
a:hover { text-decoration: underline; }
/* no underline for buttons */
a.btn { text-decoration: none !important; }
a.btn:hover { text-decoration: none !important; }

/* footer */
.footer { color: var(--secondary-text); text-align: center; padding: 2rem 1rem; font-size: 0.9rem; }

/* animations */
.fade-in { opacity: 0; transform: translateY(18px); animation: fadeInUp 0.7s ease-out forwards; }
.delay-200 { animation-delay: 0.2s; } .delay-400 { animation-delay: 0.4s; }
.delay-600 { animation-delay: 0.6s; } .delay-800 { animation-delay: 0.8s; }
.delay-1000 { animation-delay: 1s; } .delay-1200 { animation-delay: 1.2s; }
.delay-1400 { animation-delay: 1.4s; }
@keyframes fadeInUp { to { opacity: 1; transform: translateY(0); } }

/* responsive */
@media (max-width: 768px) { .info h1 { font-size: 1.6rem; } .content h2 { font-size: 1.2rem; } }
@media (max-width: 480px) { .actions { width: 100%; flex-direction: column; } .btn { width: 100%; } }