html, body { height: 100%; }
body { margin: 0; overflow-y: auto; }

.frame {
  display: grid;
  grid-template-columns: var(--rail-w) minmax(0, 1fr) var(--rail-w);
  min-height: 100dvh;
}

.rail {
  position: sticky;
  top: 0;
  align-self: start;
  height: 100dvh;
  background: var(--bg);
  display: flex;
  flex-direction: column;
  align-items: center;
  padding-block: 1.5rem;
  z-index: 10;
  transition: background var(--transition-base) ease;
}

.frame > :nth-child(2) { min-width: 0; }

.content {
  width: min(100% - 2rem, var(--content-max));
  margin-inline: auto;
  padding: clamp(1rem, 3dvw, 2rem) 1rem;
}

.brand {
  display: grid;
  grid-template-rows: auto auto;
  place-items: center;
  gap: 1rem;
  text-decoration: none;
  color: inherit;
  padding: 1rem;
  transition: all var(--transition-base) ease;
}
.brand:hover .brand__logo {
  transform: perspective(500px) rotateY(15deg) rotateX(-5deg) scale(1.1);
  filter: drop-shadow(0 8px 24px color-mix(in oklab, var(--accent-purple), transparent 60%));
}
.brand:hover .brand__name {
  transform: rotate(180deg) perspective(500px) translateZ(10px);
  letter-spacing: 0.16em;
}
.brand:hover .brand__role {
  transform: rotate(180deg) perspective(500px) translateZ(8px);
  color: var(--accent-purple);
}
.brand:focus-visible { outline: 2px solid var(--accent-purple); outline-offset: 2px; }

.brand__logo {
  inline-size: 100px;
  block-size: 100px;
  border-radius: 50%;
  transition: all var(--transition-slow) ease;
  filter: drop-shadow(0 4px 12px color-mix(in oklab, var(--accent-purple), transparent 80%));
}

.brand__text { display: flex; gap: 0.5rem; align-items: flex-start; }

.brand__name,
.brand__role {
  writing-mode: vertical-rl;
  text-orientation: mixed;
  transform: rotate(180deg);
  line-height: 1;
  transition: all var(--transition-slow) ease;
}

.brand__name {
  font-weight: 800;
  font-size: clamp(0.95rem, 0.4rem + 3vw, 1.4rem);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  background: linear-gradient(180deg, var(--ink) 0%, color-mix(in oklab, var(--ink), var(--accent-purple) 30%) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  transform-style: preserve-3d;
}

.brand__role {
  font-weight: 600;
  font-size: clamp(0.65rem, 0.4rem + 0.8vw, 0.8rem);
  letter-spacing: 0.18em;
  color: var(--muted);
  transform-style: preserve-3d;
  align-self: flex-start;
}

.rail--nav {
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  align-items: stretch;
  padding-block: 1rem;
  gap: 1.5rem;
}

.theme-toggle {
  align-self: center;
  margin-block-end: 0.5rem;
  padding: 0.5em 0.75em;
  border-radius: var(--radius-sm);
  background: color-mix(in oklab, var(--surface), white 6%);
  border: 1px solid var(--border);
  cursor: pointer;
  color: var(--ink);
  font-size: 1.25rem;
  transition: all var(--transition-base) ease;
}
.theme-toggle:hover {
  background: color-mix(in oklab, var(--accent-purple), transparent 85%);
  border-color: var(--accent-purple);
  transform: rotate(180deg) scale(1.1);
}
.theme-toggle:active { transform: rotate(180deg) scale(0.95); }

.vnav {
  display: grid;
  place-items: center;
  gap: 0.75rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.vnav a {
  display: inline-block;
  padding: 0.7em 1em;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: clamp(0.9rem, 0.75rem + 0.5vw, 1rem);
  color: var(--ink);
  text-decoration: none;
  transition: all var(--transition-base) ease;
  background: transparent;
  border: 1px solid transparent;
  position: relative;
  overflow: hidden;
}
.vnav a::before {
  content: '';
  position: absolute;
  inset-block-start: 0;
  inset-inline-start: -100%;
  inline-size: 100%;
  block-size: 100%;
  background: linear-gradient(135deg, var(--accent-purple), var(--accent-red));
  transition: inset-inline-start var(--transition-base) ease;
  z-index: -1;
}
.vnav a:hover {
  transform: translateY(-2px);
  border-color: var(--accent-purple);
  color: white;
  box-shadow: 0 4px 12px color-mix(in oklab, var(--accent-purple), transparent 75%);
}
.vnav a:hover::before { inset-inline-start: 0; }
.vnav a:active { transform: translateY(0); }
.vnav a:focus-visible { outline: 2px solid var(--accent-purple); outline-offset: 2px; }

.vnav a[aria-current="page"] {
  background: linear-gradient(135deg, var(--accent-purple), var(--accent-red));
  color: white;
  border-color: transparent;
  box-shadow: 0 4px 16px color-mix(in oklab, var(--accent-purple), transparent 70%);
}
.vnav a[aria-current="page"]:hover {
  transform: translateY(-2px) scale(1.02);
  box-shadow: 0 6px 20px color-mix(in oklab, var(--accent-purple), transparent 65%);
}

@media (max-width: 820px) {
  .frame {
    grid-template-columns: 1fr;
    grid-template-rows: auto 1fr auto;
    min-height: 100dvh;
  }

  .rail--brand {
    grid-row: 1;
    grid-column: 1;
    position: sticky;
    top: 0;
    height: auto;
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.5rem;
    backdrop-filter: blur(8px);
    background: color-mix(in oklab, var(--bg), transparent 5%);
    z-index: 100;
  }

  .brand { gap: 0.75rem; grid-template-rows: auto; grid-template-columns: auto 1fr; padding: 0; }
  .brand:hover .brand__logo { transform: perspective(500px) rotateY(-15deg) scale(1.1); }
  .brand:hover .brand__name { transform: perspective(500px) translateZ(10px); }
  .brand:hover .brand__role { transform: perspective(500px) translateZ(8px); color: var(--accent-purple); }

  .brand__logo { inline-size: 48px; block-size: 48px; }
  .brand__text { flex-direction: column; align-items: flex-start; gap: 0.25rem; }
  .brand__name, .brand__role { writing-mode: horizontal-tb; transform: none; }
  .brand__name { font-size: clamp(0.95rem, 2.5vw, 1.1rem); letter-spacing: 0.08em; }
  .brand__role { font-size: clamp(0.65rem, 1.8vw, 0.75rem); letter-spacing: 0.12em; }

  .rail--nav {
    grid-row: 3;
    grid-column: 1;
    position: sticky;
    bottom: 0;
    height: auto;
    flex-direction: row;
    justify-content: center;
    padding: 0.75rem 1rem;
    backdrop-filter: blur(8px);
    background: color-mix(in oklab, var(--bg), transparent 5%);
    z-index: 100;
    gap: 1rem;
  }

  .theme-toggle {
    position: absolute;
    inset-block-start: 50%;
    inset-inline-end: 1rem;
    transform: translateY(-50%);
    margin: 0;
    font-size: 1.1rem;
    padding: 0.4em 0.6em;
  }

  .vnav { grid-auto-flow: column; gap: 0.5rem; justify-content: center; width: 100%; }
  .vnav a { padding: 0.6em 1.2em; font-size: 0.9rem; }
}

@media (max-width: 480px) {
  .rail--brand { padding: 0.75rem 1rem; }
  .brand__logo { inline-size: 40px; block-size: 40px; }
  .brand__name { font-size: 0.85rem; }
  .brand__role { font-size: 0.6rem; }
  .rail--nav { padding: 0.5rem; }
  .vnav { gap: 0.25rem; }
  .vnav a { padding: 0.5em 0.8em; font-size: 0.85rem; }
  .theme-toggle { inset-inline-end: 0.5rem; font-size: 1rem; padding: 0.35em 0.5em; }
}