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

:root {
  --color-bg:        #ffffff;
  --color-primary:   #1a1a2e;
  --color-accent:    #0070d2;
  --color-text:      #333333;
  --color-muted:     #666666;
  --color-border:    #e0e0e0;
  --color-section-bg:#f7f9fc;
  --font-heading:    'Raleway', sans-serif;
  --font-body:       'Open Sans', sans-serif;
  --max-width:       860px;
  --nav-height:      64px;
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
}

/* ─── Navigation ───────────────────────────────────────────────────── */
nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-height);
  background: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 2rem;
  z-index: 100;
}

nav .logo-text {
  font-family: var(--font-heading);
  font-size: 1.4rem;
  font-weight: 700;
  color: #ffffff;
  letter-spacing: 0.05em;
  text-decoration: none;
}

nav ul {
  list-style: none;
  display: flex;
  gap: 2rem;
  align-items: center;
}

nav ul a {
  color: rgba(255,255,255,0.85);
  text-decoration: none;
  font-family: var(--font-heading);
  font-size: 0.875rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  transition: color 0.2s;
}

nav ul a:hover { color: #ffffff; }

nav ul a[target="_blank"]::after {
  content: ' ↗';
  font-size: 0.7em;
  opacity: 0.6;
}

.lang-switch {
  color: rgba(255,255,255,0.5) !important;
  font-size: 0.75rem !important;
  border: 1px solid rgba(255,255,255,0.25);
  padding: 0.2rem 0.5rem;
  transition: color 0.2s, border-color 0.2s !important;
}

.lang-switch:hover {
  color: #ffffff !important;
  border-color: rgba(255,255,255,0.6);
}

/* ─── Page Content ─────────────────────────────────────────────────── */
.page-content {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: calc(var(--nav-height) + 4rem) 2rem 5rem;
}

.page-title {
  font-family: var(--font-heading);
  font-size: clamp(1.8rem, 4vw, 2.5rem);
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 0.5rem;
  padding-bottom: 0.75rem;
  border-bottom: 3px solid var(--color-accent);
  display: inline-block;
}

.update-date {
  font-size: 0.875rem;
  color: var(--color-muted);
  margin-top: 0.5rem;
  margin-bottom: 2.5rem;
}

h2 {
  font-family: var(--font-heading);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-primary);
  margin-top: 2.5rem;
  margin-bottom: 0.75rem;
}

h3 {
  font-family: var(--font-heading);
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-primary);
  margin-top: 1.75rem;
  margin-bottom: 0.5rem;
}

p {
  font-size: 1rem;
  margin-bottom: 1rem;
  color: var(--color-text);
}

.page-content ul {
  margin: 0 0 1rem 1.5rem;
}

.page-content ul li {
  font-size: 1rem;
  margin-bottom: 0.5rem;
  color: var(--color-text);
}

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

a:hover { text-decoration: underline; }

/* ─── Footer ───────────────────────────────────────────────────────── */
footer {
  background: var(--color-primary);
  padding: 2rem;
  text-align: center;
}

footer p {
  color: rgba(255,255,255,0.55);
  font-size: 0.85rem;
  margin-bottom: 0.5rem;
}

footer a {
  color: rgba(255,255,255,0.7);
  text-decoration: none;
  margin: 0 0.5rem;
  font-size: 0.85rem;
  transition: color 0.2s;
}

footer a:hover { color: #ffffff; }

/* ─── Responsive ───────────────────────────────────────────────────── */
@media (max-width: 640px) {
  nav ul { gap: 1rem; }
  nav ul a { font-size: 0.75rem; }
}

@media (max-width: 480px) {
  nav { padding: 0 1rem; }
  nav ul { gap: 0.75rem; }
  nav ul a[target="_blank"]::after { display: none; }
}