/* ==========================================================================
   Klimakætteren — design system
   Art direction: the existing book identity. Signal yellow, black ink,
   a blunt serif. Pamphlet, not brochure.
   ========================================================================== */

:root,
[data-theme='light'] {
  /* Type scale */
  --text-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.875rem);
  --text-sm: clamp(0.875rem, 0.8rem + 0.35vw, 1rem);
  --text-base: clamp(1rem, 0.95rem + 0.25vw, 1.125rem);
  --text-lg: clamp(1.125rem, 1rem + 0.75vw, 1.5rem);
  --text-xl: clamp(1.5rem, 1.2rem + 1.25vw, 2.25rem);
  --text-2xl: clamp(2rem, 1.2rem + 2.5vw, 3.5rem);
  --text-3xl: clamp(2.5rem, 1rem + 4vw, 5rem);

  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  --space-32: 8rem;

  /* Surfaces — warm paper */
  --color-bg: #fbf8f0;
  --color-surface: #ffffff;
  --color-surface-offset: #f2eee1;
  --color-divider: #e0dac9;
  --color-border: #cfc8b4;

  /* Ink */
  --color-text: #16150f;
  --color-text-muted: #5d5a4d;
  --color-text-faint: #918d7d;
  --color-text-inverse: #fbf8f0;

  /* The brand: signal yellow as a field, ink as the action colour */
  --color-accent: #ffe500;
  --color-accent-deep: #e6ce00;
  --color-on-accent: #16150f;

  --color-primary: #16150f;
  --color-primary-hover: #000000;

  --radius-sm: 0.25rem;
  --radius-md: 0.375rem;
  --radius-lg: 0.5rem;
  --radius-full: 9999px;

  --transition-interactive: 180ms cubic-bezier(0.16, 1, 0.3, 1);

  --shadow-sm: 0 1px 2px rgb(22 21 15 / 0.07);
  --shadow-md: 0 6px 18px rgb(22 21 15 / 0.1);
  --shadow-lg: 0 18px 48px rgb(22 21 15 / 0.16);

  --content-narrow: 640px;
  --content-default: 960px;
  --content-wide: 1220px;

  --font-display: 'Zodiak', 'Iowan Old Style', Georgia, serif;
  --font-body: 'Switzer', 'Helvetica Neue', system-ui, sans-serif;
}

[data-theme='dark'] {
  --color-bg: #14140f;
  --color-surface: #1d1c16;
  --color-surface-offset: #24231b;
  --color-divider: #302e24;
  --color-border: #413e30;
  --color-text: #edeadf;
  --color-text-muted: #a09c8c;
  --color-text-faint: #6f6c5f;
  --color-text-inverse: #14140f;
  --color-accent: #ffe500;
  --color-accent-deep: #ffe500;
  --color-on-accent: #14140f;
  --color-primary: #ffe500;
  --color-primary-hover: #fff35c;
  --shadow-sm: 0 1px 2px rgb(0 0 0 / 0.4);
  --shadow-md: 0 6px 18px rgb(0 0 0 / 0.5);
  --shadow-lg: 0 18px 48px rgb(0 0 0 / 0.6);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --color-bg: #14140f;
    --color-surface: #1d1c16;
    --color-surface-offset: #24231b;
    --color-divider: #302e24;
    --color-border: #413e30;
    --color-text: #edeadf;
    --color-text-muted: #a09c8c;
    --color-text-faint: #6f6c5f;
    --color-text-inverse: #14140f;
    --color-primary: #ffe500;
    --color-primary-hover: #fff35c;
  }
}

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

html {
  -webkit-text-size-adjust: none;
  text-size-adjust: none;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  scroll-behavior: smooth;
  scroll-padding-top: var(--space-16);
}

body {
  min-height: 100dvh;
  line-height: 1.6;
  font-family: var(--font-body);
  font-size: var(--text-base);
  color: var(--color-text);
  background-color: var(--color-bg);
}

img,
picture,
svg {
  display: block;
  max-width: 100%;
  height: auto;
}

h1,
h2,
h3 {
  text-wrap: balance;
  line-height: 1.08;
  font-family: var(--font-display);
  font-weight: 700;
  letter-spacing: -0.015em;
}

p {
  text-wrap: pretty;
  max-width: 68ch;
}

button {
  cursor: pointer;
  background: none;
  border: none;
  font: inherit;
  color: inherit;
}

a {
  color: inherit;
  transition:
    color var(--transition-interactive),
    background var(--transition-interactive),
    border-color var(--transition-interactive),
    box-shadow var(--transition-interactive),
    transform var(--transition-interactive);
}

::selection {
  background: var(--color-accent);
  color: var(--color-on-accent);
}

:focus-visible {
  outline: 3px solid var(--color-text);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

[data-theme='dark'] :focus-visible {
  outline-color: var(--color-accent);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ---------- layout ---------- */
.wrap {
  width: 100%;
  max-width: var(--content-wide);
  margin-inline: auto;
  padding-inline: clamp(var(--space-5), 4vw, var(--space-12));
}

.wrap--narrow {
  max-width: var(--content-default);
}

.section {
  padding-block: clamp(var(--space-16), 9vw, var(--space-32));
}

/* ---------- header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in oklab, var(--color-bg) 88%, transparent);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-divider);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  min-height: 4.25rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
}

.brand__mark {
  flex: none;
  width: 1.875rem;
  height: 1.875rem;
  color: var(--color-text);
}

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.brand__name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.0625rem;
  letter-spacing: -0.01em;
}

.brand__by {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: clamp(var(--space-3), 2vw, var(--space-8));
}

.site-nav__link {
  font-size: var(--text-sm);
  text-decoration: none;
  color: var(--color-text-muted);
  padding-block: var(--space-2);
  border-bottom: 2px solid transparent;
}

.site-nav__link:hover {
  color: var(--color-text);
  border-bottom-color: var(--color-accent);
}

.theme-toggle {
  display: grid;
  place-items: center;
  width: 2.25rem;
  height: 2.25rem;
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border);
  color: var(--color-text-muted);
}

.theme-toggle:hover {
  color: var(--color-text);
  border-color: var(--color-text);
}

@media (max-width: 34rem) {
  .site-nav__link {
    display: none;
  }
  .site-nav__link--keep {
    display: inline-block;
  }
}

/* ---------- hero ---------- */
.hero {
  position: relative;
  background: var(--color-accent);
  color: var(--color-on-accent);
  overflow: hidden;
  border-bottom: 3px solid var(--color-text);
}

[data-theme='dark'] .hero {
  border-bottom-color: var(--color-accent-deep);
}

.hero__inner {
  position: relative;
  z-index: 1;
  padding-block: clamp(var(--space-16), 11vw, var(--space-32));
  display: grid;
  gap: clamp(var(--space-8), 5vw, var(--space-16));
  grid-template-columns: 1fr;
  align-items: center;
}

@media (min-width: 62rem) {
  .hero__inner {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
  }
}

.hero__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  padding: var(--space-2) var(--space-4);
  border: 2px solid var(--color-on-accent);
  border-radius: var(--radius-full);
  margin-bottom: var(--space-6);
}

.hero__title {
  font-size: var(--text-3xl);
  letter-spacing: -0.03em;
  margin-bottom: var(--space-5);
}

.hero__lead {
  font-size: var(--text-lg);
  max-width: 30ch;
  color: color-mix(in oklab, var(--color-on-accent) 82%, transparent);
  margin-bottom: var(--space-8);
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  align-items: center;
}

.hero__meta {
  margin-top: var(--space-8);
  font-size: var(--text-sm);
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2) var(--space-6);
  color: color-mix(in oklab, var(--color-on-accent) 72%, transparent);
}

.hero__meta span {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
}

/* Decorative turbine-cross, bleeding off the hero edge */
.hero__glyph {
  position: absolute;
  right: -6%;
  top: 50%;
  translate: 0 -50%;
  width: min(46rem, 52vw);
  color: var(--color-on-accent);
  opacity: 0.07;
  pointer-events: none;
  z-index: 0;
}

@media (max-width: 62rem) {
  .hero__glyph {
    right: -22%;
    width: 34rem;
  }
}

/* Stack of cover images in the hero */
.hero__stack {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-4);
  align-items: end;
  max-width: 30rem;
  margin-inline: auto;
}

.hero__stack img {
  width: 100%;
  aspect-ratio: 1 / 1.414;
  object-fit: cover;
  border: 2px solid var(--color-text);
  box-shadow: var(--shadow-lg);
  border-radius: 2px;
}

.hero__stack img:nth-child(1) {
  rotate: -4deg;
  translate: 0 var(--space-3);
}

.hero__stack img:nth-child(2) {
  rotate: 1deg;
  scale: 1.08;
  z-index: 2;
}

.hero__stack img:nth-child(3) {
  rotate: 5deg;
  translate: 0 var(--space-4);
}

/* ---------- buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.01em;
  text-decoration: none;
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius-md);
  border: 2px solid transparent;
  white-space: nowrap;
}

.btn svg {
  flex: none;
}

.btn--primary {
  background: var(--color-text);
  color: var(--color-bg);
  border-color: var(--color-text);
}

.btn--primary:hover {
  background: var(--color-primary-hover);
  border-color: var(--color-primary-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

[data-theme='dark'] .btn--primary {
  background: var(--color-accent);
  color: var(--color-on-accent);
  border-color: var(--color-accent);
}

/* On the yellow hero the ink button must stay ink in both themes */
.hero .btn--primary {
  background: #16150f;
  color: #ffe500;
  border-color: #16150f;
}

.hero .btn--primary:hover {
  background: #000;
  border-color: #000;
}

.btn--ghost {
  background: transparent;
  border-color: currentColor;
  color: inherit;
}

.btn--ghost:hover {
  background: color-mix(in oklab, currentColor 10%, transparent);
}

.btn--block {
  width: 100%;
}

/* ---------- section heads ---------- */
.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-4);
  flex-wrap: wrap;
  padding-bottom: var(--space-5);
  border-bottom: 2px solid var(--color-text);
  margin-bottom: clamp(var(--space-8), 4vw, var(--space-12));
}

.section-head__title {
  font-size: var(--text-xl);
}

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

/* ---------- featured book ---------- */
.featured {
  display: grid;
  gap: clamp(var(--space-6), 4vw, var(--space-12));
  grid-template-columns: 1fr;
  align-items: start;
  padding-bottom: clamp(var(--space-12), 6vw, var(--space-20));
  margin-bottom: clamp(var(--space-12), 6vw, var(--space-20));
  border-bottom: 1px solid var(--color-divider);
}

@media (min-width: 50rem) {
  .featured {
    grid-template-columns: minmax(0, 0.8fr) minmax(0, 1.2fr);
  }
}

.featured__cover {
  position: relative;
  display: block;
  border: 2px solid var(--color-text);
  border-radius: 2px;
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  background: var(--color-surface);
}

.featured__cover img {
  width: 100%;
  aspect-ratio: 1 / 1.414;
  object-fit: cover;
}

.featured__badge {
  display: inline-block;
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  background: var(--color-accent);
  color: var(--color-on-accent);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  margin-bottom: var(--space-4);
}

.featured__title {
  font-size: var(--text-2xl);
  margin-bottom: var(--space-4);
}

.featured__subtitle {
  font-size: var(--text-lg);
  color: var(--color-text-muted);
  margin-bottom: var(--space-6);
}

.featured__actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-top: var(--space-8);
}

/* ---------- book grid ---------- */
.book-grid {
  display: grid;
  gap: clamp(var(--space-6), 3vw, var(--space-10));
  grid-template-columns: repeat(auto-fill, minmax(15rem, 1fr));
}

.book-card {
  display: flex;
  flex-direction: column;
  height: 100%;
}

.book-card__cover {
  display: block;
  position: relative;
  border: 2px solid var(--color-text);
  border-radius: 2px;
  overflow: hidden;
  background: var(--color-surface);
  box-shadow: var(--shadow-sm);
}

.book-card__cover img {
  width: 100%;
  aspect-ratio: 1 / 1.414;
  object-fit: cover;
  transition: scale var(--transition-interactive);
}

.book-card__cover:hover {
  box-shadow: var(--shadow-md);
}

.book-card__cover:hover img {
  scale: 1.025;
}

.book-card__body {
  padding-top: var(--space-5);
  display: flex;
  flex-direction: column;
  flex: 1;
}

.book-card__title {
  font-size: var(--text-lg);
  margin-bottom: var(--space-2);
}

.book-card__subtitle {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-4);
}

.book-card__meta {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: var(--space-4);
  display: flex;
  gap: var(--space-3);
  flex-wrap: wrap;
}

.book-card__foot {
  margin-top: auto;
}

/* ---------- about ---------- */
.about {
  background: var(--color-surface-offset);
  border-block: 1px solid var(--color-divider);
}

.about__grid {
  display: grid;
  gap: clamp(var(--space-8), 5vw, var(--space-16));
  grid-template-columns: 1fr;
}

@media (min-width: 52rem) {
  .about__grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  }
}

.about__title {
  font-size: var(--text-xl);
  margin-bottom: var(--space-6);
}

.about__body p + p {
  margin-top: var(--space-4);
}

.pull {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  line-height: 1.3;
  padding-left: var(--space-6);
  border-left: 4px solid var(--color-accent);
  margin-block: var(--space-8);
}

.pull cite {
  display: block;
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-style: normal;
  color: var(--color-text-muted);
  margin-top: var(--space-3);
}

/* ---------- footer ---------- */
.site-footer {
  padding-block: var(--space-12);
  border-top: 1px solid var(--color-divider);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

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

.site-footer a {
  color: var(--color-text-muted);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

.site-footer a:hover {
  color: var(--color-text);
}

/* ---------- scroll reveal ---------- */
@media (prefers-reduced-motion: no-preference) {
  .reveal {
    opacity: 0;
    transform: translateY(18px);
    transition:
      opacity 600ms cubic-bezier(0.16, 1, 0.3, 1),
      transform 600ms cubic-bezier(0.16, 1, 0.3, 1);
  }
  .reveal.is-visible {
    opacity: 1;
    transform: none;
  }
}