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

.container--narrow {
  max-width: var(--container-narrow);
  margin: 0 auto;
  padding: 0 var(--container-px);
}

/* ── Header ── */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(250, 250, 250, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.header.is-scrolled {
  border-color: var(--color-border);
  box-shadow: var(--shadow-sm);
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.header__logo {
  font-size: var(--text-xl);
  font-weight: var(--font-bold);
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.02em;
}

.header__nav {
  display: flex;
  align-items: center;
  gap: var(--space-6);
}

.header__nav-link {
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-text-muted);
  transition: color var(--transition);
}

.header__nav-link:hover {
  color: var(--color-primary);
}

.header__menu-btn {
  display: none;
  flex-direction: column;
  gap: 5px;
  width: 28px;
  padding: 4px;
}

.header__menu-btn span {
  display: block;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}

/* Mobile Nav Drawer */
.mobile-nav {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 200;
}

.mobile-nav.is-open { display: flex; }

.mobile-nav__overlay {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.4);
}

.mobile-nav__panel {
  position: absolute;
  top: 0;
  right: 0;
  width: 280px;
  height: 100%;
  background: var(--color-bg-card);
  padding: var(--space-6);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  animation: slideIn 0.25s ease;
}

@keyframes slideIn {
  from { transform: translateX(100%); }
  to   { transform: translateX(0); }
}

.mobile-nav__close {
  align-self: flex-end;
  font-size: var(--text-xl);
  color: var(--color-text-muted);
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  transition: background var(--transition);
}

.mobile-nav__close:hover { background: var(--color-primary-light); }

.mobile-nav__link {
  font-size: var(--text-lg);
  font-weight: var(--font-medium);
  color: var(--color-text);
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--color-border);
  transition: color var(--transition);
}

.mobile-nav__link:hover { color: var(--color-primary); }

/* ── Footer ── */
.footer {
  margin-top: var(--space-16);
  border-top: 1px solid var(--color-border);
  background: var(--color-bg-card);
}

.footer__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-8) 0;
  gap: var(--space-4);
  flex-wrap: wrap;
}

.footer__copy {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.footer__links {
  display: flex;
  gap: var(--space-6);
}

.footer__link {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  transition: color var(--transition);
}

.footer__link:hover { color: var(--color-primary); }

/* ── Main Wrapper ── */
.main {
  min-height: calc(100vh - 64px - 120px);
  padding: var(--space-12) 0;
}

/* ── Section Title ── */
.section-title {
  font-size: var(--text-2xl);
  font-weight: var(--font-bold);
  margin-bottom: var(--space-8);
  position: relative;
  display: inline-block;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -6px;
  left: 0;
  width: 40px;
  height: 3px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-secondary));
  border-radius: var(--radius-full);
}

/* ── Back to Top ── */
.back-to-top {
  position: fixed;
  bottom: var(--space-8);
  right: var(--space-8);
  width: 44px;
  height: 44px;
  border-radius: var(--radius-full);
  background: var(--color-primary);
  color: var(--color-text-on-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-lg);
  box-shadow: var(--shadow-md);
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition), transform var(--transition);
  z-index: 50;
}

.back-to-top.is-visible {
  opacity: 1;
  pointer-events: auto;
}

.back-to-top:hover { transform: translateY(-2px); }

/* ── Responsive ── */
@media (max-width: 768px) {
  .header__nav-link { display: none; }
  .header__menu-btn { display: flex; }

  .footer__inner {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }

  .back-to-top {
    bottom: var(--space-6);
    right: var(--space-6);
  }
}