.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  backdrop-filter: blur(14px);
  background: color-mix(in srgb, var(--bg) 84%, transparent);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  min-height: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand {
  font-family: "Roboto", "Segoe UI", sans-serif;
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: 0.03em;
  color: var(--primary);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 1.35rem;
}

.site-nav a {
  position: relative;
  color: var(--muted);
  transition: color 200ms ease;
}

.site-nav a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -0.35rem;
  width: 100%;
  height: 1px;
  background: var(--primary);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 220ms ease;
}

.site-nav a:hover,
.site-nav a:focus-visible {
  color: var(--primary);
}

.site-nav a:hover::after,
.site-nav a:focus-visible::after {
  transform: scaleX(1);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.65rem;
}

.menu-toggle,
.control-btn {
  border: 1px solid var(--line);
  background: var(--surface);
  min-height: 2.35rem;
  border-radius: 999px;
  padding: 0.42rem 0.95rem;
  font-size: 0.84rem;
  font-weight: 500;
  color: var(--text);
  transition: transform 180ms ease, border-color 180ms ease;
}

.menu-toggle:hover,
.control-btn:hover {
  transform: translateY(-1px);
  border-color: var(--primary);
}

.menu-toggle {
  display: none;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.95rem;
  border-radius: 999px;
  padding: 0.62rem 1.32rem;
  font-weight: 500;
  font-size: 0.9rem;
  border: 1px solid transparent;
  transition: transform 180ms ease, background 220ms ease, color 220ms ease, border-color 220ms ease;
}

.btn:hover {
  transform: translateY(-2px);
}

.btn-solid {
  background: var(--accent);
  color: #ffffff;
  border-color: color-mix(in srgb, var(--accent) 76%, #2f3338);
}

.btn-solid:hover {
  background: color-mix(in srgb, var(--accent) 86%, #2f3338);
}

.btn-outline {
  border-color: var(--line);
  background: transparent;
  color: var(--text);
}

.btn-outline:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
}

.feature-card {
  border: 1px solid var(--line);
  background: linear-gradient(145deg, var(--surface), var(--surface-soft));
  border-radius: 20px;
  padding: 1.5rem;
  display: grid;
  gap: 0.7rem;
  box-shadow: var(--shadow);
}

.feature-card p {
  color: var(--muted);
}

.site-footer {
  padding: 1.8rem 0 2.4rem;
}

.footer-inner {
  border-top: 1px solid var(--line);
  padding-top: 1.4rem;
  color: var(--muted);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.75rem;
}

@media (max-width: 920px) {
  .feature-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 780px) {
  .menu-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
  }

  .site-nav {
    position: absolute;
    top: 76px;
    left: 0;
    right: 0;
    background: var(--surface);
    border-bottom: 1px solid var(--line);
    display: grid;
    gap: 0;
    padding: 0.4rem 1rem 0.8rem;
    max-height: 0;
    overflow: hidden;
    transition: max-height 220ms ease;
  }

  .site-nav.is-open {
    max-height: 260px;
  }

  .site-nav a {
    padding: 0.6rem 0.3rem;
  }

  .header-actions {
    margin-left: auto;
  }
}