:root {
  /* Colors — clean white page background with black top notice accent */
  --color-bg: #ffffff;
  --color-bg-subtle: #f8fafc;
  --color-bg-muted: #f1f5f9;
  --color-card-bg: #ffffff;
  --color-card-border: #e2e8f0;
  --color-text: #0f172a;
  --color-text-secondary: #334155;
  --color-text-muted: #64748b;
  --color-accent: #0284c7;
  --color-accent-hover: #0369a1;
  --color-accent-subtle: rgba(2, 132, 199, 0.1);
  --color-border: #e2e8f0;
  --color-border-light: #f1f5f9;
  --color-success: #15803d;
  --color-success-bg: rgba(21, 128, 61, 0.08);
  --color-success-border: rgba(21, 128, 61, 0.25);

  /* Typography */
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    Helvetica, Arial, sans-serif;
  --font-mono: "SF Mono", SFMono-Regular, Consolas, "Liberation Mono", Menlo,
    monospace;

  /* Font sizes */
  --text-hero: clamp(2.5rem, 6vw, 4.5rem);
  --text-h1: clamp(2rem, 4vw, 3rem);
  --text-h2: clamp(1.5rem, 3vw, 2rem);
  --text-h3: 1.25rem;
  --text-body: 1.125rem;
  --text-small: 0.9375rem;
  --text-xs: 0.8125rem;

  /* Line heights */
  --leading-tight: 1.15;
  --leading-normal: 1.6;
  --leading-relaxed: 1.75;

  /* Spacing */
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 2.5rem;
  --space-xl: 4rem;
  --space-2xl: 6rem;
  --space-3xl: 8rem;

  /* Layout */
  --max-width: 720px;
  --max-width-wide: 960px;
  --radius-sm: 6px;
  --radius-md: 12px;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.08);
  --shadow-glow: 0 0 30px rgba(2, 132, 199, 0.15);
}

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

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  background-color: var(--color-bg);
  color-scheme: light;
}

body {
  font-family: var(--font-sans);
  font-size: var(--text-body);
  line-height: var(--leading-normal);
  color: var(--color-text);
  background-color: var(--color-bg);
}

/* Page wrapper */
.page {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  position: relative;
  background-color: var(--color-bg);
}

/* Section layout */
.section {
  width: 100%;
  padding: var(--space-2xl) var(--space-md);
}

.section--alt {
  background-color: var(--color-bg-subtle);
  border-top: 1px solid var(--color-border-light);
  border-bottom: 1px solid var(--color-border-light);
}

.section__inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.section__inner--wide {
  max-width: var(--max-width-wide);
}

/* Responsive breakpoints */
@media (max-width: 768px) {
  .section {
    padding: var(--space-xl) var(--space-sm);
  }
}

@media (max-width: 480px) {
  .section {
    padding: var(--space-lg) var(--space-sm);
  }
}

/* ============================================
   Top Announcement Banner (Black Theme Notice Banner)
   ============================================ */
.top-banner {
  background: #000000;
  border-bottom: 1px solid rgba(255, 255, 255, 0.14);
  padding: 0.875rem 1.5rem;
  text-align: center;
  font-size: 0.9375rem;
  line-height: 1.5;
  color: #f8fafc;
  position: relative;
  z-index: 90;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
}

.top-banner__inner {
  max-width: 900px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  flex-wrap: wrap;
}

.top-banner__tag {
  display: inline-block;
  background: #18181b;
  color: #ffffff;
  border: 1px solid rgba(255, 255, 255, 0.25);
  padding: 0.15rem 0.6rem;
  border-radius: 9999px;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.top-banner__content {
  color: rgba(255, 255, 255, 0.95);
  font-weight: 500;
}

/* Version Tag */
.version-tag {
  position: absolute;
  top: 2rem;
  right: 2rem;
  display: flex;
  align-items: center;
  gap: 1rem;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  font-size: 0.875rem;
  z-index: 100;
}

.version-tag__label {
  font-weight: 700;
  color: #8e8e93;
  font-family: var(--font-mono);
  letter-spacing: -0.02em;
}

/* ============================================
   Hero
   ============================================ */
.hero {
  min-height: 85vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--space-3xl) var(--space-md);
  background: radial-gradient(circle at 50% 30%, rgba(10, 132, 255, 0.08) 0%, transparent 70%);
}

.hero__inner {
  max-width: var(--max-width);
}

.hero__headline {
  font-size: var(--text-hero);
  font-weight: 700;
  line-height: var(--leading-tight);
  letter-spacing: -0.03em;
  color: #0f172a;
  margin-bottom: var(--space-md);
}

.hero__subheadline {
  font-size: var(--text-h3);
  font-weight: 400;
  line-height: var(--leading-relaxed);
  color: var(--color-text-secondary);
  max-width: 580px;
  margin: 0 auto var(--space-lg);
}

.hero__cta {
  display: inline-block;
  padding: 0.875rem 2.25rem;
  font-size: var(--text-body);
  font-weight: 600;
  color: #ffffff;
  background-color: var(--color-accent);
  border: none;
  border-radius: 8px;
  cursor: pointer;
  text-decoration: none;
  box-shadow: 0 4px 14px rgba(2, 132, 199, 0.25);
  transition: background-color var(--transition-fast),
    transform var(--transition-fast),
    box-shadow var(--transition-fast);
}

.hero__cta:hover {
  background-color: var(--color-accent-hover);
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(2, 132, 199, 0.35);
}

.hero__cta:active {
  transform: translateY(0);
}

/* ============================================
   Section headings
   ============================================ */
.section__label {
  font-size: var(--text-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-xs);
}

.section__title {
  font-size: var(--text-h1);
  font-weight: 700;
  line-height: var(--leading-tight);
  letter-spacing: -0.02em;
  color: #0f172a;
  margin-bottom: var(--space-md);
}

.section__body {
  font-size: var(--text-body);
  line-height: var(--leading-relaxed);
  color: var(--color-text-secondary);
}

.section__body p {
  margin-bottom: var(--space-sm);
}

.section__body p:last-child {
  margin-bottom: 0;
}

.section__body strong {
  color: var(--color-text);
  font-weight: 600;
}

.section__link {
  display: inline-block;
  margin-top: var(--space-md);
  font-size: var(--text-small);
  font-weight: 600;
  color: var(--color-accent);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.section__link:hover {
  color: var(--color-accent-hover);
}

/* ============================================
   Plan items
   ============================================ */
.plan-items {
  list-style: none;
  margin-top: var(--space-md);
}

.plan-item {
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--color-border-light);
}

.plan-item:last-child {
  border-bottom: none;
}

.plan-item__title {
  font-weight: 600;
  color: #0f172a;
  margin-bottom: 0.25rem;
}

.plan-item__desc {
  font-size: var(--text-small);
  color: var(--color-text-secondary);
  line-height: var(--leading-normal);
}

.plan-item__desc p {
  margin-bottom: var(--space-sm);
}

.plan-item__desc p:last-child {
  margin-bottom: 0;
}

/* ============================================
   Sign-up form & Cards
   ============================================ */
.form {
  margin-top: var(--space-lg);
}

.form__group {
  margin-bottom: var(--space-md);
}

.form__label {
  display: block;
  font-size: var(--text-small);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 0.375rem;
}

.form__hint {
  display: block;
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-bottom: 0.375rem;
}

.form__input,
.form__textarea {
  width: 100%;
  padding: 0.75rem 1rem;
  font-family: var(--font-sans);
  font-size: var(--text-body);
  color: var(--color-text);
  background-color: #ffffff;
  border: 1.5px solid var(--color-border);
  border-radius: 8px;
  outline: none;
  transition: border-color var(--transition-fast),
    box-shadow var(--transition-fast),
    background-color var(--transition-fast);
}

.form__input:focus,
.form__textarea:focus {
  background-color: #ffffff;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px var(--color-accent-subtle);
}

.form__textarea {
  min-height: 120px;
  resize: vertical;
}

.form__submit {
  display: inline-block;
  padding: 0.875rem 2.25rem;
  font-family: var(--font-sans);
  font-size: var(--text-body);
  font-weight: 600;
  color: #fff;
  background-color: var(--color-accent);
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: background-color var(--transition-fast),
    transform var(--transition-fast);
}

.form__submit:hover {
  background-color: var(--color-accent-hover);
  transform: translateY(-1px);
}

.form__submit:active {
  transform: translateY(0);
}

.form__submit:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

/* ============================================
   Transparency toggle
   ============================================ */
.transparency {
  margin-top: var(--space-md);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  overflow: hidden;
}

.transparency__toggle {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1rem;
  background-color: #f8fafc;
  border: none;
  width: 100%;
  cursor: pointer;
  font-family: var(--font-sans);
  font-size: var(--text-small);
  font-weight: 600;
  color: var(--color-text-secondary);
  transition: background-color var(--transition-fast);
}

.transparency__toggle:hover {
  background-color: #f1f5f9;
}

.transparency__icon {
  font-size: var(--text-xs);
  transition: transform var(--transition-normal);
}

.transparency__icon--open {
  transform: rotate(180deg);
}

.transparency__payload {
  display: none;
  padding: 1rem;
  background-color: #f1f5f9;
  border-top: 1px solid var(--color-border);
}

.transparency__payload--visible {
  display: block;
}

.transparency__code {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-text-secondary);
  white-space: pre-wrap;
  word-break: break-word;
  line-height: 1.6;
}

/* ============================================
   Privacy statement
   ============================================ */
.privacy-note {
  margin-top: var(--space-md);
  padding: var(--space-sm) var(--space-md);
  background-color: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--color-border-light);
  border-radius: 8px;
  font-size: var(--text-small);
  color: var(--color-text-muted);
  line-height: var(--leading-relaxed);
}

/* ============================================
   Resources
   ============================================ */
.resource-cards {
  display: grid;
  gap: var(--space-md);
  margin-top: var(--space-md);
}

.resource-card {
  padding: var(--space-md);
  background-color: var(--color-card-bg);
  border: 1px solid var(--color-card-border);
  border-radius: 8px;
  transition: box-shadow var(--transition-normal);
}

.resource-card:hover {
  box-shadow: var(--shadow-md);
}

.resource-card__title {
  font-size: var(--text-h3);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 0.5rem;
}

.resource-card__desc {
  font-size: var(--text-small);
  color: var(--color-text-secondary);
  line-height: var(--leading-normal);
}

/* ============================================
   Footer
   ============================================ */
.footer {
  padding: var(--space-lg) var(--space-md);
  border-top: 1px solid var(--color-border-light);
  text-align: center;
  background-color: var(--color-bg);
}

.footer__inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.footer__brand {
  font-size: var(--text-small);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 0.25rem;
}

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

/* ============================================
   Scroll-reveal animation
   ============================================ */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal--visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================
   Success message
   ============================================ */
.form__success {
  display: none;
  padding: var(--space-md);
  background-color: var(--color-success-bg);
  border: 1px solid var(--color-success-border);
  border-radius: 8px;
  color: var(--color-success);
  font-weight: 600;
  text-align: center;
}

.form__success--visible {
  display: block;
}

/* ============================================
   Share URL
   ============================================ */
.share-url {
  display: none;
  margin-top: var(--space-md);
  padding: var(--space-sm) var(--space-md);
  background-color: #f8fafc;
  border: 1px solid var(--color-border);
  border-radius: 8px;
}

.share-url--visible {
  display: block;
}

.share-url__label {
  font-size: var(--text-small);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 0.375rem;
}

.share-url__row {
  display: flex;
  gap: 0.5rem;
}

.share-url__input {
  flex: 1;
  padding: 0.5rem 0.75rem;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-text-secondary);
  background-color: #ffffff;
  border: 1px solid var(--color-border);
  border-radius: 6px;
  outline: none;
}

.share-url__copy {
  padding: 0.5rem 1rem;
  font-family: var(--font-sans);
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--color-accent);
  background-color: transparent;
  border: 1.5px solid var(--color-accent);
  border-radius: 6px;
  cursor: pointer;
  white-space: nowrap;
  transition: background-color var(--transition-fast),
    color var(--transition-fast);
}

.share-url__copy:hover {
  background-color: var(--color-accent);
  color: #ffffff;
}