@layer components {
  app-shell:not(:defined),
  book-card:not(:defined),
  book-rating:not(:defined) {
    visibility: hidden;
  }

  .site-header {
    position: sticky;
    inset-block-start: 0;
    z-index: 10;
    background: color-mix(in srgb, var(--color-page) 92%, transparent);
    border-block-end: var(--line);
    backdrop-filter: blur(14px);
  }

  .site-header__inner {
    inline-size: min(100% - 2rem, var(--max-width));
    min-block-size: 4.5rem;
    margin-inline: auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-4);
  }

  .brand {
    display: inline-flex;
    align-items: center;
    gap: var(--space-3);
    font-family: var(--font-display);
    font-size: clamp(1.4rem, 3vw, 2rem);
    font-weight: 700;
    text-decoration: none;
  }

  .brand img {
    inline-size: 3rem;
    block-size: 3rem;
    border-radius: var(--radius-1);
  }

  .site-nav {
    display: flex;
    align-items: center;
    gap: var(--space-4);
  }

  .site-nav a {
    padding-block: var(--space-2);
    text-decoration: none;
    color: var(--color-muted);
    border-block-end: 2px solid transparent;
  }

  .site-nav a[aria-current] {
    color: var(--color-text);
    border-color: var(--color-accent);
  }

  .button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    min-block-size: 2.75rem;
    padding-inline: var(--space-4);
    border: 1px solid var(--color-primary);
    border-radius: var(--radius-1);
    background: var(--color-primary);
    color: #fff;
    font-weight: 700;
    text-decoration: none;
  }

  .button.secondary {
    background: transparent;
    color: var(--color-primary);
  }

  .button:hover {
    background: var(--color-primary-strong);
  }

  .button.secondary:hover {
    background: color-mix(in srgb, var(--color-primary) 8%, transparent);
  }

  .eyebrow {
    margin: 0 0 var(--space-2);
    color: var(--color-accent);
    font-size: 0.78rem;
    font-weight: 800;
    letter-spacing: 0.08em;
    text-transform: uppercase;
  }

  h1,
  h2,
  h3 {
    font-family: var(--font-display);
    line-height: 1.05;
  }

  h1 {
    margin: 0 0 var(--space-4);
    font-size: clamp(2.4rem, 5vw, 4.4rem);
  }

  h2 {
    margin-block: 0 var(--space-3);
    font-size: clamp(1.7rem, 4vw, 3rem);
  }

  .card,
  .filter-panel {
    border: var(--line);
    border-radius: var(--radius-2);
    background: var(--color-surface);
  }

  .filter-panel {
    padding: var(--space-4);
  }

  .filter-panel[data-active],
  .filter-panel:has(input:not(:placeholder-shown)) {
    border-color: color-mix(in srgb, var(--color-accent) 75%, var(--color-border));
    background: color-mix(in srgb, var(--color-accent-soft) 45%, white);
  }

  .field {
    display: grid;
    gap: var(--space-1);
  }

  .field span {
    color: var(--color-muted);
    font-size: 0.85rem;
    font-weight: 700;
  }

  .field input,
  .field select,
  customer-name {
    inline-size: 100%;
    min-block-size: 2.75rem;
  }

  input,
  select {
    border: var(--line);
    border-radius: var(--radius-1);
    background: #fff;
    color: var(--color-text);
    padding-inline: var(--space-3);
  }

  form:has(:user-invalid) .form-status,
  form:has(customer-name:state(user-invalid)) .form-status {
    color: var(--color-danger);
  }

  input:user-invalid {
    border-color: var(--color-danger);
  }

  /* customer-name exposes a matching custom state; overriding --line recolors
     its shadow input's border, since custom properties cross the shadow. */
  customer-name:state(user-invalid) {
    --line: 1px solid var(--color-danger);
  }

  input:user-valid {
    border-color: color-mix(in srgb, var(--color-primary) 65%, var(--color-border));
  }

  .book-cover {
    position: relative;
    isolation: isolate;
    display: grid;
    grid-template-rows: 1fr auto 1fr;
    align-items: center;
    justify-items: center;
    gap: var(--space-3);
    aspect-ratio: 3 / 4;
    border-radius: var(--radius-1);
    background:
      radial-gradient(circle at 50% 72%, color-mix(in srgb, var(--color-accent) 26%, transparent), transparent 28%),
      linear-gradient(145deg, color-mix(in srgb, var(--color-primary) 92%, black), var(--color-primary));
    box-shadow: 0 1.1rem 2.4rem color-mix(in srgb, var(--color-primary) 22%, transparent);
    color: #fff;
    font-family: var(--font-display);
    padding: clamp(var(--space-4), 7cqi, var(--space-6));
    text-align: center;
    text-decoration: none;
    overflow: hidden;
  }

  .book-cover::before,
  .book-cover::after {
    position: absolute;
    z-index: -1;
    content: "";
    border: 1px solid color-mix(in srgb, #fff 18%, transparent);
    opacity: 0.7;
  }

  .book-cover::before {
    inset: 0.6rem;
  }

  .book-cover::after {
    inline-size: 5rem;
    block-size: 5rem;
    inset-block-end: 18%;
    inset-inline-end: -1.6rem;
    border-radius: 50%;
    background: color-mix(in srgb, var(--color-accent) 28%, transparent);
  }

  .book-cover__title {
    align-self: end;
    max-inline-size: 10ch;
    font-size: clamp(1.35rem, 16cqi, 2.4rem);
    line-height: 1.05;
  }

  .book-cover__mark {
    color: color-mix(in srgb, var(--color-accent) 82%, white);
    font-size: clamp(1rem, 11cqi, 1.8rem);
    font-weight: 700;
    letter-spacing: 0.06em;
  }

  .book-cover__author {
    align-self: end;
    font-family: var(--font-ui);
    font-size: clamp(0.58rem, 4.5cqi, 0.72rem);
    font-weight: 800;
    letter-spacing: 0.16em;
    text-transform: uppercase;
  }

  .book-cover__ornament {
    inline-size: min(7rem, 45%);
    block-size: min(7rem, 45%);
    border-radius: 60% 40% 55% 45%;
    background:
      linear-gradient(50deg, transparent 48%, color-mix(in srgb, var(--color-accent) 78%, white) 49% 52%, transparent 53%),
      radial-gradient(ellipse at 40% 20%, color-mix(in srgb, var(--color-accent) 78%, white) 0 24%, transparent 25%),
      radial-gradient(ellipse at 68% 38%, color-mix(in srgb, var(--color-accent) 78%, white) 0 20%, transparent 21%),
      radial-gradient(ellipse at 35% 65%, color-mix(in srgb, var(--color-accent) 78%, white) 0 18%, transparent 19%);
  }

  .book-cover--hero {
    inline-size: min(100%, 14rem);
    justify-self: center;
  }

  .book-cover[data-book="designing-with-web-standards"],
  .book-cover[data-book="small-habits"] {
    background:
      radial-gradient(circle at 78% 78%, color-mix(in srgb, var(--color-accent) 30%, transparent), transparent 25%),
      linear-gradient(145deg, #f7efd9, #fffaf0);
    color: var(--color-text);
  }

  .book-cover[data-book="wander-north"] {
    background:
      radial-gradient(circle at 50% 70%, rgba(255, 255, 255, 0.18), transparent 30%),
      linear-gradient(145deg, #124f5a, #0b2f36);
  }

  .store-hero__copy {
    max-inline-size: 34rem;
  }

  .store-hero__copy > p:not(.eyebrow, .cluster, .book-price) {
    font-size: 1.05rem;
    line-height: 1.7;
  }

  .hero-price {
    margin-block: var(--space-5);
    font-size: 1.35rem;
  }

  .book-price {
    color: var(--color-primary);
    font-weight: 800;
  }

  .home-loading {
    min-block-size: 40vh;
    display: grid;
    place-items: center;
    color: var(--color-muted);
  }

  .intro-card {
    padding: var(--space-6);
  }

  .mini-cart {
    padding: var(--space-5);
  }

  .mini-cart__header,
  .mini-cart__total,
  .mini-cart__list li {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-3);
  }

  .mini-cart h2 {
    margin: 0;
    font-family: var(--font-ui);
    font-size: 1.05rem;
  }

  .mini-cart__list {
    display: grid;
    gap: var(--space-3);
    padding: 0;
    margin: var(--space-5) 0;
    list-style: none;
  }

  .mini-cart__list li {
    display: grid;
    grid-template-columns: auto minmax(0, 1fr) auto auto;
  }

  .mini-cart__list span:not(.book-cover) {
    font-weight: 700;
  }

  .mini-cart__list small {
    color: var(--color-muted);
  }

  .mini-cart__empty {
    margin-block: var(--space-5);
  }

  .mini-cart__total {
    padding-block-start: var(--space-4);
    border-block-start: var(--line);
  }

  .mini-cart__button {
    inline-size: 100%;
    margin-block-start: var(--space-4);
  }

  .catalog-filter {
    min-inline-size: 7rem;
  }

  .book-card {
    container-type: inline-size;
    display: grid;
    gap: var(--space-4);
    padding: var(--space-4);
  }

  .book-card h2 {
    font-family: var(--font-ui);
    font-size: 1.05rem;
    line-height: 1.2;
  }

  .book-card h2 a {
    text-decoration: none;
  }

  .book-card__body {
    display: grid;
    gap: var(--space-2);
  }

  .book-card__body p {
    margin: 0;
  }

  .book-card__footer {
    display: flex;
    justify-content: space-between;
    gap: var(--space-3);
    align-items: center;
    margin-block-start: var(--space-2);
  }

  @container (min-width: 22rem) {
    .book-card {
      grid-template-columns: 8rem 1fr;
    }
  }

  .book-cover.mini {
    inline-size: 3rem;
    block-size: 4rem;
    aspect-ratio: auto;
    padding: var(--space-2);
    box-shadow: none;
  }

  .book-cover.mini .book-cover__mark {
    font-size: 0.85rem;
  }

  .cart-list {
    display: grid;
    gap: var(--space-3);
    padding: 0;
    margin: var(--space-6) 0;
    list-style: none;
  }

  .cart-row {
    display: grid;
    grid-template-columns: auto minmax(0, 1fr) auto;
    gap: var(--space-4);
    align-items: center;
    padding: var(--space-4);
  }

  .cart-total {
    font-size: 1.4rem;
  }

  quantity-stepper {
    display: inline-grid;
    grid-template-columns: 2.25rem 2.5rem 2.25rem;
    align-items: center;
    border: var(--line);
    border-radius: var(--radius-1);
    overflow: hidden;
  }

  quantity-stepper button {
    min-block-size: 2.25rem;
    border: 0;
    background: var(--color-surface-muted);
  }

  quantity-stepper output {
    text-align: center;
  }

  .checkout-form {
    display: grid;
    max-inline-size: 34rem;
    gap: var(--space-4);
  }

  code {
    border-radius: var(--radius-1);
    background: var(--color-surface-muted);
    padding: 0.1rem 0.25rem;
  }
}

@layer utilities {
  .cluster {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-3);
    align-items: center;
  }

  .muted {
    color: var(--color-muted);
  }

  .visually-hidden {
    position: absolute;
    inline-size: 1px;
    block-size: 1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
    white-space: nowrap;
  }

  @media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
      scroll-behavior: auto !important;
      transition-duration: 0.01ms !important;
      animation-duration: 0.01ms !important;
    }
  }
}