/* =========================================================
   Eurotherm 2028 — light, bright, themeable.
   Five POC color schemes selected via the theme picker in the header.
   ========================================================= */

:root {
  /* Type scale */
  --text-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.8125rem);
  --text-sm: clamp(0.875rem, 0.8rem + 0.25vw, 0.9375rem);
  --text-base: clamp(1rem, 0.95rem + 0.2vw, 1.0625rem);
  --text-lg: clamp(1.125rem, 1rem + 0.6vw, 1.375rem);
  --text-xl: clamp(1.5rem, 1.2rem + 1.2vw, 2.125rem);
  --text-2xl: clamp(2rem, 1.2rem + 2.5vw, 3.25rem);
  --text-3xl: clamp(2.5rem, 1rem + 4vw, 4.5rem);

  /* 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;

  /* Status (theme-independent) */
  --color-success: #2f7a44;
  --color-success-bg: #e3f1e6;
  --color-warning: #b07a00;
  --color-warning-bg: #f7ecc9;
  --color-error: #b3322c;
  --color-error-bg: #fadcd8;

  /* Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 14px;
  --radius-full: 9999px;

  --transition-interactive: 200ms cubic-bezier(0.16, 1, 0.3, 1);

  --content-narrow: 720px;
  --content-default: 1040px;
  --content-wide: 1240px;

  --font-display: 'Fraunces', 'Iowan Old Style', Georgia, serif;
  --font-body: 'Inter', 'Helvetica Neue', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', 'IBM Plex Mono', ui-monospace, monospace;
}

/* =========================================================
   THEME PALETTES — five POC themes, all light & bright
   ========================================================= */

/* 1 · COPPER — warm cream + copper heat (default) */
:root,
[data-theme='copper'] {
  --color-bg: #fbf6ec;
  --color-surface: #ffffff;
  --color-surface-2: #fffdf7;
  --color-surface-offset: #f3ead6;
  --color-divider: #e6dcc4;
  --color-border: #d3c7a8;

  --color-text: #2a2520;
  --color-text-muted: #6a6358;
  --color-text-faint: #a39b8c;

  --color-ink: #2a2e44;

  --color-primary: #b6532a;
  --color-primary-hover: #94411f;
  --color-primary-active: #6d2f15;
  --color-primary-highlight: #f4e0cf;

  --heat-1: #ffb070;
  --heat-2: #f48a3c;
  --heat-3: #d96b22;
  --heat-4: #f5c79b;
  --heat-5: #ffe9d2;

  --shadow-sm: 0 1px 2px rgba(70, 50, 30, 0.06);
  --shadow-md: 0 8px 24px rgba(70, 50, 30, 0.08);
  --shadow-lg: 0 22px 48px rgba(70, 50, 30, 0.12);
}

/* 2 · OCEAN — cool blue */
[data-theme='ocean'] {
  --color-bg: #f2f6fb;
  --color-surface: #ffffff;
  --color-surface-2: #f9fbfe;
  --color-surface-offset: #e3ecf6;
  --color-divider: #d4dfeb;
  --color-border: #b9c8db;

  --color-text: #18243a;
  --color-text-muted: #54657f;
  --color-text-faint: #95a3bb;

  --color-ink: #182849;

  --color-primary: #1862a8;
  --color-primary-hover: #134d83;
  --color-primary-active: #0c365e;
  --color-primary-highlight: #d6e6f6;

  --heat-1: #6dafe2;
  --heat-2: #3a82c4;
  --heat-3: #1862a8;
  --heat-4: #a4cdec;
  --heat-5: #dcecf8;

  --shadow-sm: 0 1px 2px rgba(20, 50, 90, 0.06);
  --shadow-md: 0 8px 24px rgba(20, 50, 90, 0.08);
  --shadow-lg: 0 22px 48px rgba(20, 50, 90, 0.12);
}

/* 3 · FOREST — fresh sage / pine */
[data-theme='forest'] {
  --color-bg: #f3f7f0;
  --color-surface: #ffffff;
  --color-surface-2: #fafcf8;
  --color-surface-offset: #e3eedb;
  --color-divider: #d2dfc7;
  --color-border: #b6c7a8;

  --color-text: #1d2a1d;
  --color-text-muted: #57674f;
  --color-text-faint: #98a58c;

  --color-ink: #1f3320;

  --color-primary: #2f7a44;
  --color-primary-hover: #245d33;
  --color-primary-active: #194124;
  --color-primary-highlight: #d8ecdb;

  --heat-1: #7fbf8a;
  --heat-2: #4f9a5f;
  --heat-3: #2f7a44;
  --heat-4: #b3d6b6;
  --heat-5: #e0eeda;

  --shadow-sm: 0 1px 2px rgba(30, 60, 30, 0.06);
  --shadow-md: 0 8px 24px rgba(30, 60, 30, 0.08);
  --shadow-lg: 0 22px 48px rgba(30, 60, 30, 0.12);
}

/* 4 · PLUM — soft lavender + aubergine */
[data-theme='plum'] {
  --color-bg: #f7f3f8;
  --color-surface: #ffffff;
  --color-surface-2: #fcfaff;
  --color-surface-offset: #ece2ee;
  --color-divider: #ddd0e0;
  --color-border: #c2b1c8;

  --color-text: #2a1d2e;
  --color-text-muted: #685a6e;
  --color-text-faint: #a597a8;

  --color-ink: #2d1f3a;

  --color-primary: #7a3a8a;
  --color-primary-hover: #5d296a;
  --color-primary-active: #3f1948;
  --color-primary-highlight: #ecdcef;

  --heat-1: #c08fcc;
  --heat-2: #9a59ab;
  --heat-3: #7a3a8a;
  --heat-4: #d6b6dd;
  --heat-5: #ece0ee;

  --shadow-sm: 0 1px 2px rgba(60, 30, 70, 0.06);
  --shadow-md: 0 8px 24px rgba(60, 30, 70, 0.08);
  --shadow-lg: 0 22px 48px rgba(60, 30, 70, 0.12);
}

/* 5 · SLATE — neutral graphite + accent */
[data-theme='slate'] {
  --color-bg: #f4f5f7;
  --color-surface: #ffffff;
  --color-surface-2: #fafbfc;
  --color-surface-offset: #e4e7ec;
  --color-divider: #d6d9df;
  --color-border: #b9bdc6;

  --color-text: #1c1f25;
  --color-text-muted: #5a606c;
  --color-text-faint: #97a1ad;

  --color-ink: #1f2330;

  --color-primary: #2f4858;
  --color-primary-hover: #1f3340;
  --color-primary-active: #131f29;
  --color-primary-highlight: #d9e2e8;

  --heat-1: #6f8a99;
  --heat-2: #486578;
  --heat-3: #2f4858;
  --heat-4: #a8bac4;
  --heat-5: #dde4ea;

  --shadow-sm: 0 1px 2px rgba(20, 30, 40, 0.06);
  --shadow-md: 0 8px 24px rgba(20, 30, 40, 0.08);
  --shadow-lg: 0 22px 48px rgba(20, 30, 40, 0.12);
}

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

html {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  scroll-behavior: smooth;
  scroll-padding-top: var(--space-20);
}

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,
svg {
  display: block;
  max-width: 100%;
  height: auto;
}
button {
  cursor: pointer;
  background: none;
  border: none;
  color: inherit;
  font: inherit;
}
input,
button,
textarea,
select {
  font: inherit;
  color: inherit;
}
a {
  color: var(--color-primary);
  text-decoration: none;
  text-underline-offset: 3px;
}
a:hover {
  text-decoration: underline;
}

h1,
h2,
h3,
h4 {
  font-family: var(--font-display);
  font-weight: 500;
  letter-spacing: -0.015em;
  line-height: 1.1;
  color: var(--color-text);
  font-variation-settings: 'SOFT' 50, 'WONK' 0, 'opsz' 144;
  font-feature-settings: 'ss01' off, 'ss02' off;
}
h1 {
  font-size: var(--text-2xl);
}
h2 {
  font-size: var(--text-xl);
}
h3 {
  font-size: var(--text-lg);
}
p,
li {
  text-wrap: pretty;
}

::selection {
  background: var(--color-primary-highlight);
  color: var(--color-text);
}
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

a,
button,
[role='button'],
input,
textarea,
select {
  transition:
    color var(--transition-interactive),
    background var(--transition-interactive),
    border-color var(--transition-interactive),
    box-shadow var(--transition-interactive);
}

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

.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;
}

/* =========================================================
   Layout helpers
   ========================================================= */
.container {
  width: 100%;
  max-width: var(--content-wide);
  padding-inline: clamp(var(--space-4), 4vw, var(--space-12));
  margin-inline: auto;
}
.container--narrow {
  max-width: var(--content-default);
}
.section {
  padding-block: clamp(var(--space-12), 6vw, var(--space-24));
}
.section--tight {
  padding-block: clamp(var(--space-10), 4vw, var(--space-16));
}

/* =========================================================
   Header
   ========================================================= */
.demo-banner {
  background: var(--color-primary-highlight);
  border-bottom: 1px solid color-mix(in oklab, var(--color-primary) 25%, transparent);
  font-size: 0.8125rem;
  text-align: center;
  padding: 0.55rem var(--space-4);
  color: var(--color-text);
}
.demo-banner strong {
  color: var(--color-primary);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in oklab, var(--color-bg) 92%, transparent);
  backdrop-filter: saturate(140%) blur(12px);
  border-bottom: 1px solid var(--color-divider);
}
.site-header__inner {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding-block: var(--space-4);
}
.site-header__brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  color: var(--color-text);
}
.site-header__brand:hover {
  text-decoration: none;
}
.brand-mark {
  width: 38px;
  height: 38px;
  flex: 0 0 38px;
}
.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.05;
}
.brand-text strong {
  font-family: var(--font-display);
  font-size: 1.0625rem;
  letter-spacing: -0.01em;
  font-weight: 600;
}
.brand-text span {
  font-size: 0.6875rem;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  color: var(--color-text-muted);
}
.site-nav {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: var(--space-1);
}
.site-nav a {
  color: var(--color-text);
  font-size: 0.9375rem;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-sm);
  text-decoration: none;
}
.site-nav a:hover {
  color: var(--color-primary);
  text-decoration: none;
}
.site-nav a.is-active {
  color: var(--color-primary);
  background: var(--color-primary-highlight);
}

/* Header tools (theme picker, language) */
.header-tools {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.lang-toggle {
  display: inline-flex;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  overflow: hidden;
  background: var(--color-surface);
}
.lang-toggle button {
  padding: 0.35rem 0.6rem;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--color-text-muted);
}
.lang-toggle button.is-active {
  background: var(--color-primary);
  color: #fff;
}

/* Theme picker */
.theme-picker {
  position: relative;
}
.theme-picker__btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  padding: 0.3rem 0.55rem 0.3rem 0.45rem;
  background: var(--color-surface);
  font-size: 0.8125rem;
  color: var(--color-text);
}
.theme-picker__btn:hover {
  border-color: var(--color-primary);
}
.theme-picker__swatch {
  width: 16px;
  height: 16px;
  border-radius: var(--radius-full);
  background: linear-gradient(135deg, var(--heat-2), var(--color-primary));
  border: 1px solid color-mix(in oklab, var(--color-text) 12%, transparent);
}
.theme-picker__menu {
  position: absolute;
  top: calc(100% + 6px);
  right: 0;
  background: var(--color-surface);
  border: 1px solid var(--color-divider);
  border-radius: var(--radius-md);
  padding: var(--space-2);
  box-shadow: var(--shadow-lg);
  display: none;
  min-width: 220px;
  z-index: 60;
}
.theme-picker.is-open .theme-picker__menu {
  display: block;
}
.theme-picker__menu button {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  width: 100%;
  padding: 0.55rem 0.65rem;
  font-size: 0.875rem;
  border-radius: var(--radius-sm);
  color: var(--color-text);
}
.theme-picker__menu button:hover {
  background: var(--color-surface-offset);
}
.theme-picker__menu button.is-active {
  background: var(--color-primary-highlight);
  color: var(--color-primary);
  font-weight: 600;
}
.theme-picker__menu .swatch {
  width: 18px;
  height: 18px;
  border-radius: var(--radius-full);
  border: 1px solid rgba(0, 0, 0, 0.08);
  flex: 0 0 18px;
}

.menu-toggle {
  display: none;
  width: 38px;
  height: 38px;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
}
@media (max-width: 1080px) {
  .site-nav {
    display: none;
    position: absolute;
    inset-inline: 0;
    top: 100%;
    flex-direction: column;
    align-items: stretch;
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-divider);
    padding: var(--space-3);
    box-shadow: var(--shadow-md);
  }
  .site-nav a {
    padding: var(--space-3);
  }
  .site-nav.is-open {
    display: flex;
  }
  .menu-toggle {
    display: inline-flex;
  }
  .site-header__cta {
    display: none;
  }
}

/* =========================================================
   Buttons
   ========================================================= */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 0.7rem 1.1rem;
  font-size: 0.9375rem;
  font-weight: 500;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  text-decoration: none;
  white-space: nowrap;
  line-height: 1;
}
.btn:hover {
  text-decoration: none;
}
.btn--primary {
  background: var(--color-primary);
  color: #fff;
  box-shadow: var(--shadow-sm);
}
.btn--primary:hover {
  background: var(--color-primary-hover);
}
.btn--ghost {
  background: var(--color-surface);
  color: var(--color-text);
  border-color: var(--color-border);
}
.btn--ghost:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}
.btn--lg {
  padding: 0.95rem 1.5rem;
  font-size: 1rem;
}
.btn--block {
  width: 100%;
  justify-content: center;
}

/* =========================================================
   Hero
   ========================================================= */
.hero {
  position: relative;
  padding-block: clamp(var(--space-16), 9vw, var(--space-32)) clamp(var(--space-12), 6vw, var(--space-24));
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute;
  top: -10%;
  right: -5%;
  width: 50%;
  height: 80%;
  background: radial-gradient(circle, var(--color-primary-highlight), transparent 70%);
  opacity: 0.5;
  pointer-events: none;
  z-index: -1;
}
.hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr);
  gap: clamp(var(--space-8), 5vw, var(--space-16));
  align-items: center;
}
@media (max-width: 900px) {
  .hero__grid {
    grid-template-columns: 1fr;
  }
}
.hero__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: var(--space-5);
}
.hero__eyebrow::before {
  content: '';
  width: 28px;
  height: 1px;
  background: var(--color-primary);
}
.hero h1 {
  font-size: var(--text-3xl);
  font-weight: 400;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-6);
}
.hero h1 em {
  font-style: italic;
  color: var(--color-primary);
}
.hero__lede {
  font-size: var(--text-lg);
  color: var(--color-text-muted);
  max-width: 60ch;
  margin-bottom: var(--space-8);
}
.hero__meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-6) var(--space-10);
  margin-bottom: var(--space-8);
}
.hero__meta-item {
  border-left: 2px solid var(--color-primary);
  padding-left: var(--space-3);
}
.hero__meta-item span {
  display: block;
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  color: var(--color-text-muted);
  margin-bottom: 0.2rem;
}
.hero__meta-item strong {
  font-family: var(--font-display);
  font-size: 1.125rem;
  font-weight: 500;
}
.hero__cta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

/* Isotherm illustration */
.hero__visual {
  position: relative;
  aspect-ratio: 1 / 1;
  border-radius: var(--radius-lg);
  background: var(--color-surface);
  border: 1px solid var(--color-divider);
  padding: var(--space-6);
  box-shadow: var(--shadow-md);
  overflow: hidden;
}
.hero__visual svg {
  width: 100%;
  height: 100%;
}
.hero__visual-caption {
  position: absolute;
  bottom: var(--space-5);
  left: var(--space-6);
  right: var(--space-6);
  display: flex;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-text-muted);
}

/* Marquee — slower, larger, far more readable */
.marquee {
  border-block: 1px solid var(--color-divider);
  background: var(--color-surface);
  padding-block: var(--space-6);
  overflow: hidden;
  position: relative;
  mask-image: linear-gradient(90deg, transparent, #000 8%, #000 92%, transparent);
}
.marquee__track {
  display: flex;
  gap: clamp(var(--space-10), 6vw, var(--space-16));
  font-family: var(--font-display);
  font-size: 1.125rem;
  font-weight: 500;
  color: var(--color-text);
  white-space: nowrap;
  animation: marquee 90s linear infinite;
  width: max-content;
  align-items: center;
}
.marquee__item {
  display: inline-flex;
  align-items: baseline;
  gap: var(--space-3);
}
.marquee__item .yr {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  color: var(--color-primary);
}
.marquee__item .city {
  font-style: italic;
}
.marquee__item .sep {
  color: var(--color-border);
  font-family: var(--font-body);
  font-style: normal;
}
@media (prefers-reduced-motion: reduce) {
  .marquee__track {
    animation: none;
  }
}
@keyframes marquee {
  to {
    transform: translateX(-50%);
  }
}

/* =========================================================
   Sections / cards
   ========================================================= */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: var(--space-3);
}
.eyebrow::before {
  content: '';
  width: 24px;
  height: 1px;
  background: var(--color-primary);
}
.section__head {
  max-width: 52ch;
  margin-bottom: var(--space-10);
}
.section__head p {
  color: var(--color-text-muted);
  margin-top: var(--space-3);
}

.grid-cols-2 {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-6);
}
.grid-cols-3 {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: var(--space-6);
}
.grid-cols-4 {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--space-6);
}
@media (max-width: 900px) {
  .grid-cols-3,
  .grid-cols-4 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}
@media (max-width: 600px) {
  .grid-cols-2,
  .grid-cols-3,
  .grid-cols-4 {
    grid-template-columns: 1fr;
  }
}

.card {
  background: var(--color-surface);
  border: 1px solid var(--color-divider);
  border-radius: var(--radius-md);
  padding: var(--space-6);
  transition:
    border-color var(--transition-interactive),
    box-shadow var(--transition-interactive),
    transform var(--transition-interactive);
}
.card:hover {
  border-color: var(--color-primary);
}
.card h3 {
  margin-bottom: var(--space-2);
}
.card p {
  color: var(--color-text-muted);
}

.feature-card {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  height: 100%;
}
.feature-card .icon {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  background: var(--color-primary-highlight);
  color: var(--color-primary);
  display: grid;
  place-items: center;
}

/* Important dates */
.dates {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--space-4);
}
.date {
  background: var(--color-surface);
  border: 1px solid var(--color-divider);
  border-radius: var(--radius-md);
  padding: var(--space-5);
  position: relative;
  overflow: hidden;
}
.date::before {
  content: '';
  position: absolute;
  inset: 0 auto 0 0;
  width: 3px;
  background: var(--color-primary);
  opacity: 0.4;
}
.date[data-stage='abstract']::before { background: var(--heat-3); }
.date[data-stage='full']::before { background: var(--heat-2); }
.date[data-stage='final']::before { background: var(--heat-1); }
.date[data-stage='registration']::before { background: var(--color-success); }
.date[data-stage='conference']::before { background: var(--color-ink); opacity: 1; }
.date__label {
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: var(--space-2);
}
.date__value {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 500;
}

/* Topics */
.topics {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-8);
}
@media (max-width: 700px) {
  .topics { grid-template-columns: 1fr; }
}
.topics ul {
  list-style: none;
  columns: 2;
  column-gap: var(--space-6);
}
.topics li {
  font-size: 0.9375rem;
  padding: 0.35rem 0;
  border-bottom: 1px dashed var(--color-divider);
  break-inside: avoid;
}
@media (max-width: 600px) {
  .topics ul { columns: 1; }
}

/* =========================================================
   Pricing
   ========================================================= */
.pricing {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: var(--space-5);
}
@media (max-width: 900px) {
  .pricing { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 600px) {
  .pricing { grid-template-columns: 1fr; }
}
.tier {
  background: var(--color-surface);
  border: 1px solid var(--color-divider);
  border-radius: var(--radius-md);
  padding: var(--space-6);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  position: relative;
}
.tier--highlight {
  border-color: var(--color-primary);
  background: linear-gradient(180deg, var(--color-primary-highlight), var(--color-surface) 80%);
}
.tier__badge {
  position: absolute;
  top: -10px;
  left: var(--space-5);
  background: var(--color-primary);
  color: #fff;
  font-size: 0.6875rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: 0.25rem 0.6rem;
  border-radius: var(--radius-full);
}
.tier__label {
  font-family: var(--font-display);
  font-size: 1.25rem;
}
.tier__price {
  font-family: var(--font-display);
  font-size: 2.5rem;
  font-weight: 500;
  letter-spacing: -0.02em;
  line-height: 1;
}
.tier__price small {
  font-family: var(--font-body);
  font-size: 0.875rem;
  font-weight: 400;
  color: var(--color-text-muted);
}
.tier__deadline {
  font-size: 0.8125rem;
  color: var(--color-text-muted);
}
.tier__audience {
  font-size: 0.9375rem;
  color: var(--color-text-muted);
  margin-top: auto;
}

/* =========================================================
   Forms
   ========================================================= */
.form { display: grid; gap: var(--space-5); }
.form__row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-5);
}
@media (max-width: 600px) { .form__row { grid-template-columns: 1fr; } }
.field { display: flex; flex-direction: column; gap: var(--space-2); }
.field label { font-size: 0.875rem; font-weight: 500; }
.field label .req { color: var(--color-primary); margin-left: 2px; }
.field input,
.field textarea,
.field select {
  width: 100%;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 0.7rem 0.85rem;
  font-size: 0.9375rem;
}
.field textarea { min-height: 120px; resize: vertical; }
.field input:focus,
.field textarea:focus,
.field select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-highlight);
}
.field--error input,
.field--error textarea,
.field--error select {
  border-color: var(--color-error);
  background: var(--color-error-bg);
}
.field--error input:focus,
.field--error textarea:focus,
.field--error select:focus {
  box-shadow: 0 0 0 3px color-mix(in oklab, var(--color-error) 18%, transparent);
}
.field__error {
  display: none;
  font-size: 0.8125rem;
  color: var(--color-error);
}
.field--error .field__error {
  display: flex;
  gap: 0.35rem;
  align-items: center;
}
.field__hint { font-size: 0.8125rem; color: var(--color-text-muted); }

.checkbox {
  display: inline-flex;
  align-items: flex-start;
  gap: var(--space-3);
  font-size: 0.9375rem;
  cursor: pointer;
  line-height: 1.5;
}
.checkbox input {
  width: 18px; height: 18px; margin-top: 2px;
  accent-color: var(--color-primary);
}

.tier-pick { display: grid; gap: var(--space-3); }
.tier-pick label {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-4);
  border: 1px solid var(--color-divider);
  border-radius: var(--radius-md);
  cursor: pointer;
  background: var(--color-surface);
}
.tier-pick label:hover { border-color: var(--color-primary); }
.tier-pick input[type='radio'] {
  accent-color: var(--color-primary);
  flex: 0 0 18px; width: 18px; height: 18px; margin: 0;
}
.tier-pick label:has(input:checked) {
  border-color: var(--color-primary);
  background: var(--color-primary-highlight);
}
.tier-pick__body {
  flex: 1 1 auto;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  min-width: 0;
}
.tier-pick__price {
  font-family: var(--font-display);
  font-size: 1.25rem;
  flex: 0 0 auto;
  margin-left: auto;
}

/* Multi-step form */
.stepper {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-3);
  margin-bottom: var(--space-8);
}
.stepper__item {
  display: flex; flex-direction: column; gap: var(--space-2);
}
.stepper__bar {
  height: 4px;
  background: var(--color-divider);
  border-radius: var(--radius-full);
  overflow: hidden;
}
.stepper__bar > span {
  display: block; height: 100%; width: 0;
  background: var(--color-primary);
  transition: width 600ms cubic-bezier(0.16, 1, 0.3, 1);
}
.stepper__item.is-done .stepper__bar > span { width: 100%; }
.stepper__item.is-current .stepper__bar > span { width: 50%; }
.stepper__label {
  display: flex; align-items: center; gap: var(--space-2);
  font-size: 0.8125rem;
  color: var(--color-text-muted);
}
.stepper__label .num {
  width: 22px; height: 22px;
  border-radius: var(--radius-full);
  background: var(--color-divider);
  color: var(--color-text);
  font-size: 0.75rem; font-weight: 600;
  display: grid; place-items: center;
}
.stepper__item.is-current .stepper__label,
.stepper__item.is-done .stepper__label { color: var(--color-text); }
.stepper__item.is-current .stepper__label .num,
.stepper__item.is-done .stepper__label .num {
  background: var(--color-primary);
  color: #fff;
}

.progress-bar {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  background: var(--color-surface);
  border: 1px solid var(--color-divider);
  border-radius: var(--radius-md);
  padding: var(--space-3) var(--space-4);
  margin-bottom: var(--space-6);
  font-size: 0.875rem;
  flex-wrap: wrap;
}
.progress-bar__bar {
  flex: 1; min-width: 120px;
  height: 6px;
  background: var(--color-divider);
  border-radius: var(--radius-full);
  overflow: hidden;
}
.progress-bar__bar > span {
  display: block; height: 100%;
  background: linear-gradient(90deg, var(--heat-3), var(--heat-2));
  transition: width 400ms ease;
}
.progress-bar__pct {
  font-variant-numeric: tabular-nums;
  font-weight: 600;
  color: var(--color-primary);
}
.progress-bar__resume {
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  width: 100%;
}

.step-actions {
  display: flex;
  justify-content: space-between;
  gap: var(--space-3);
  padding-top: var(--space-4);
  border-top: 1px solid var(--color-divider);
}

.alert {
  display: flex;
  gap: var(--space-3);
  padding: var(--space-4);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-divider);
  background: var(--color-surface);
  font-size: 0.9375rem;
}
.alert--success {
  background: var(--color-success-bg);
  border-color: color-mix(in oklab, var(--color-success) 30%, transparent);
}
.alert--warning {
  background: var(--color-warning-bg);
  border-color: color-mix(in oklab, var(--color-warning) 30%, transparent);
}
.alert--error {
  background: var(--color-error-bg);
  border-color: color-mix(in oklab, var(--color-error) 30%, transparent);
}

/* =========================================================
   Tables
   ========================================================= */
table.simple {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9375rem;
  background: var(--color-surface);
  border: 1px solid var(--color-divider);
  border-radius: var(--radius-md);
  overflow: hidden;
}
table.simple th,
table.simple td {
  padding: var(--space-3) var(--space-4);
  text-align: left;
  border-bottom: 1px solid var(--color-divider);
  vertical-align: top;
}
table.simple th {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-text-muted);
  background: var(--color-surface-offset);
  font-weight: 500;
}
table.simple tr:last-child td { border-bottom: none; }

.pill {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.25rem 0.55rem;
  font-size: 0.75rem;
  font-weight: 500;
  border-radius: var(--radius-full);
  background: var(--color-divider);
  color: var(--color-text);
}
.pill--accepted { background: var(--color-success-bg); color: var(--color-success); }
.pill--review { background: var(--color-warning-bg); color: var(--color-warning); }
.pill--final { background: var(--color-primary-highlight); color: var(--color-primary); }
.pill--rejected { background: var(--color-error-bg); color: var(--color-error); }

/* Drop zone */
.dropzone {
  border: 1.5px dashed var(--color-border);
  background: var(--color-surface);
  border-radius: var(--radius-md);
  padding: var(--space-10);
  text-align: center;
  color: var(--color-text-muted);
  cursor: pointer;
  transition: all var(--transition-interactive);
}
.dropzone:hover,
.dropzone.is-dragging {
  border-color: var(--color-primary);
  background: var(--color-primary-highlight);
  color: var(--color-text);
}
.dropzone strong {
  color: var(--color-text);
  display: block;
  margin-bottom: 0.4rem;
  font-family: var(--font-display);
  font-size: 1.125rem;
}

/* =========================================================
   Program / schedule
   ========================================================= */
.day {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: var(--space-8);
  padding-block: var(--space-8);
  border-bottom: 1px solid var(--color-divider);
}
@media (max-width: 700px) { .day { grid-template-columns: 1fr; gap: var(--space-4); } }
.day h3 {
  font-family: var(--font-display);
  font-size: 1.5rem;
  position: sticky;
  top: 80px;
}
.session {
  display: grid;
  grid-template-columns: 140px 1fr;
  gap: var(--space-4);
  padding: var(--space-3) 0;
  border-bottom: 1px dashed var(--color-divider);
}
.session:last-child { border-bottom: none; }
.session__time {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--color-text-muted);
}
.session__title { font-weight: 500; }
.session__room { font-size: 0.8125rem; color: var(--color-text-muted); }

/* =========================================================
   Footer
   ========================================================= */
.site-footer {
  background: var(--color-ink);
  color: rgba(255, 255, 255, 0.78);
  padding-block: var(--space-16) var(--space-8);
  margin-top: var(--space-24);
}
.site-footer h4 {
  color: #fff;
  font-family: var(--font-display);
  font-size: 1rem;
  margin-bottom: var(--space-4);
}
.site-footer a { color: rgba(255, 255, 255, 0.78); }
.site-footer a:hover { color: var(--color-primary-highlight); text-decoration: underline; }
.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr;
  gap: var(--space-10);
}
@media (max-width: 800px) { .footer-grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 500px) { .footer-grid { grid-template-columns: 1fr; } }
.footer-grid ul {
  list-style: none;
  display: grid;
  gap: var(--space-2);
  font-size: 0.9375rem;
}
.footer-bottom {
  margin-top: var(--space-12);
  padding-top: var(--space-6);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  display: flex;
  justify-content: space-between;
  font-size: 0.8125rem;
  color: rgba(255, 255, 255, 0.55);
  flex-wrap: wrap;
  gap: var(--space-3);
}

/* =========================================================
   Login card
   ========================================================= */
.login-card {
  max-width: 420px;
  margin-inline: auto;
  background: var(--color-surface);
  border: 1px solid var(--color-divider);
  border-radius: var(--radius-md);
  padding: var(--space-10);
  box-shadow: var(--shadow-sm);
}