/* ==========================================================================
   Kasper Transactions, Design Tokens & Global Styles
   Palette: Kaspa official brand colors, teal #70C7BA, mint #49EACB,
   dark charcoal #231F20, gray #B6B6B6. Dark-leaning design to match the
   provided logo (dark charcoal background, teal/mint faceted octagon with a
   stylized K letterform, echoing Kaspa's blockDAG structure).
   ========================================================================== */

:root,
[data-theme='dark'] {
  /* Surfaces, dark charcoal base, brand guidance calls for dark clarity */
  --color-bg: #17181a;
  --color-surface: #1c1d1f;
  --color-surface-2: #202224;
  --color-surface-offset: #131415;
  --color-surface-offset-2: #0f1011;
  --color-surface-dynamic: #2a2c2e;
  --color-divider: #2c2e30;
  --color-border: #343638;

  /* Text, near-white with warm gray undertone, never pure white */
  --color-text: #edeceb;
  --color-text-muted: #b6b6b6;
  --color-text-faint: #7d7e80;
  --color-text-inverse: #231f20;

  /* Primary accent, Kaspa teal/mint */
  --color-primary: #49eacb;
  --color-primary-hover: #6ff0d6;
  --color-primary-active: #3bcaae;
  --color-primary-highlight: #1c3630;
  --color-accent-pure: #70c7ba;

  /* Secondary accent, deeper teal for depth */
  --color-copper: #70c7ba;
  --color-copper-hover: #8dd4c9;

  /* Warning */
  --color-warning: #e0a63a;
  --color-warning-hover: #ecb95c;
  --color-warning-highlight: #3d3220;

  /* Success (aligns with mint) */
  --color-success: #49eacb;
  --color-success-hover: #6ff0d6;
  --color-success-highlight: #1c3630;

  /* Error */
  --color-error: #d97060;
  --color-error-hover: #e08c7e;
  --color-error-highlight: #3d2b26;

  /* Notification */
  --color-notification: #d97060;
  --color-notification-highlight: #3d2b26;

  /* Data/chart tones */
  --color-gold: #e0a63a;
  --color-teal: #70c7ba;
  --color-slate: #b6b6b6;

  /* Radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.875rem;
  --radius-xl: 1.25rem;
  --radius-full: 9999px;

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

  /* Shadows, cool dark cast */
  --shadow-sm: 0 1px 2px oklch(0 0 0 / 0.3);
  --shadow-md: 0 6px 20px oklch(0 0 0 / 0.4);
  --shadow-lg: 0 20px 48px oklch(0 0 0 / 0.5);

  /* Content widths */
  --content-narrow: 640px;
  --content-default: 960px;
  --content-wide: 1200px;
  --content-full: 100%;

  /* Fonts */
  --font-display: 'Cabinet Grotesk', 'Segoe UI', sans-serif;
  --font-body: 'Satoshi', 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;
}

/* Kasper Transactions is dark-first by brand design; a lighter variant is
   still provided for the manual theme toggle for accessibility preference. */
[data-theme='light'] {
  --color-bg: #f4f6f5;
  --color-surface: #ffffff;
  --color-surface-2: #ffffff;
  --color-surface-offset: #eceeed;
  --color-surface-offset-2: #e3e6e5;
  --color-surface-dynamic: #d7dbda;
  --color-divider: #dde0df;
  --color-border: #ced2d1;

  --color-text: #231f20;
  --color-text-muted: #565859;
  --color-text-faint: #8b8d8e;
  --color-text-inverse: #f4f6f5;

  --color-primary: #1f9c86;
  --color-primary-hover: #17806e;
  --color-primary-active: #12665a;
  --color-primary-highlight: #d9f3ee;
  --color-accent-pure: #1f9c86;

  --color-copper: #1f9c86;
  --color-copper-hover: #17806e;

  --color-warning: #a0691a;
  --color-warning-hover: #7f5414;
  --color-warning-highlight: #f3e5cc;

  --color-success: #1f9c86;
  --color-success-hover: #17806e;
  --color-success-highlight: #d9f3ee;

  --color-error: #b23f2c;
  --color-error-hover: #90311f;
  --color-error-highlight: #f3d9d3;

  --color-notification: #b23f2c;
  --color-notification-highlight: #f3d9d3;

  --color-gold: #a0691a;
  --color-teal: #1f9c86;
  --color-slate: #565859;

  --shadow-sm: 0 1px 2px oklch(0.25 0.01 0 / 0.08);
  --shadow-md: 0 6px 16px oklch(0.25 0.01 0 / 0.1);
  --shadow-lg: 0 16px 40px oklch(0.25 0.01 0 / 0.16);
}

/* Kasper Transactions stays dark by default regardless of system color
   scheme preference. Light mode is available only via the explicit
   theme toggle, which sets [data-theme='light'] directly (see above). */

/* ==========================================================================
   Type Scale, fluid clamp()
   ========================================================================== */
:root {
  --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);
  --text-hero: clamp(2.75rem, 1rem + 6vw, 6.5rem);
}

/* ==========================================================================
   4px Spacing System
   ========================================================================== */
:root {
  --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;
}

/* ==========================================================================
   Layout primitives
   ========================================================================== */
.container {
  width: 100%;
  max-width: var(--content-wide);
  margin-inline: auto;
  padding-inline: var(--space-6);
}
.container--default {
  max-width: var(--content-default);
}
.container--narrow {
  max-width: var(--content-narrow);
}

section {
  padding-block: clamp(var(--space-16), 8vw, var(--space-32));
  position: relative;
}
section.section--tight {
  padding-block: clamp(var(--space-10), 5vw, var(--space-16));
}

/* ==========================================================================
   Header / Nav
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: oklch(from var(--color-bg) l c h / 0.88);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--color-divider);
  transition:
    transform 0.3s cubic-bezier(0.16, 1, 0.3, 1),
    box-shadow 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}
.site-header--hidden {
  transform: translateY(-100%);
}
.site-header--scrolled {
  box-shadow: var(--shadow-sm);
}
.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-6);
  padding-block: var(--space-4);
}
.brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  color: var(--color-text);
  flex-shrink: 0;
}
.brand__mark {
  width: 36px;
  height: 36px;
  flex-shrink: 0;
}
.brand__name {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: var(--text-sm);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  line-height: 1.1;
}
.brand__name span {
  display: block;
  font-family: var(--font-body);
  font-weight: 400;
  text-transform: none;
  letter-spacing: 0;
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}

.main-nav {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}
.main-nav__list {
  display: flex;
  align-items: center;
  gap: 2px;
  flex-wrap: wrap;
}
.main-nav a {
  display: inline-block;
  padding: var(--space-2) var(--space-3);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  text-decoration: none;
  border-radius: var(--radius-sm);
}
.main-nav a:hover {
  color: var(--color-text);
  background: var(--color-surface-offset);
}
.main-nav a[aria-current='page'] {
  color: var(--color-primary);
}

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

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  color: var(--color-text-muted);
}
.theme-toggle:hover {
  background: var(--color-surface-offset);
  color: var(--color-text);
}

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  color: var(--color-text);
}

/* ==========================================================================
   Buttons
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  font-family: var(--font-body);
  font-weight: 600;
  font-size: var(--text-sm);
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius-sm);
  text-decoration: none;
  border: 1px solid transparent;
  min-height: 44px;
  line-height: 1;
}
.btn--primary {
  background: var(--color-primary);
  color: var(--color-text-inverse);
}
.btn--primary:hover {
  background: var(--color-primary-hover);
}
.btn--secondary {
  background: transparent;
  color: var(--color-text);
  border-color: var(--color-border);
}
.btn--secondary:hover {
  background: var(--color-surface-offset);
  border-color: var(--color-text-muted);
}
.btn--ghost {
  background: transparent;
  color: var(--color-primary);
  padding-inline: var(--space-2);
}
.btn--ghost:hover {
  color: var(--color-primary-hover);
}
.btn--block {
  width: 100%;
}

/* ==========================================================================
   Typography helpers
   ========================================================================== */
.eyebrow {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-primary);
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
}
.eyebrow::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: var(--radius-full);
  background: var(--color-primary);
  flex-shrink: 0;
}

h1,
.h1 {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: var(--text-hero);
  letter-spacing: -0.01em;
  color: var(--color-text);
}
h2,
.h2 {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: var(--text-2xl);
  letter-spacing: -0.01em;
  color: var(--color-text);
}
h3,
.h3 {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: var(--text-xl);
  color: var(--color-text);
}
h4,
.h4 {
  font-family: var(--font-body);
  font-weight: 700;
  font-size: var(--text-lg);
  color: var(--color-text);
}
p {
  color: var(--color-text-muted);
}
.lede {
  font-size: var(--text-lg);
  color: var(--color-text-muted);
  max-width: 46ch;
}
.mono {
  font-family: var(--font-mono);
}

/* ==========================================================================
   Page hero (interior pages)
   ========================================================================== */
.page-hero {
  padding-block: clamp(var(--space-16), 10vw, var(--space-24)) clamp(var(--space-10), 6vw, var(--space-16));
  border-bottom: 1px solid var(--color-divider);
  background:
    radial-gradient(ellipse 900px 500px at 15% 0%, var(--color-primary-highlight) 0%, transparent 60%),
    var(--color-surface);
}
.page-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr);
  gap: var(--space-16);
  align-items: center;
}
.page-hero h1 {
  font-size: var(--text-2xl);
  margin-block: var(--space-4) var(--space-5);
}
.page-hero__visual {
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}

/* ==========================================================================
   Cards / grids
   ========================================================================== */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-8);
}

.stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--space-8);
}
.stat {
  border-top: 1px solid var(--color-border);
  padding-top: var(--space-4);
}
.stat__value {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 600;
  color: var(--color-primary);
  display: block;
}
.stat__label {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.feature-list {
  display: grid;
  gap: var(--space-6);
}
.feature-row {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: var(--space-6);
  padding-block: var(--space-6);
  border-bottom: 1px solid var(--color-divider);
}
.feature-row:first-child {
  padding-top: 0;
}
.feature-row:last-child {
  border-bottom: none;
}
.feature-row__index {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-text-faint);
  padding-top: var(--space-1);
}
.feature-row h4 {
  margin-bottom: var(--space-2);
}

/* ==========================================================================
   Section utilities
   ========================================================================== */
.section-head {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  margin-bottom: var(--space-12);
  max-width: 60ch;
}
.section-head--wide {
  max-width: 80ch;
}

.divider-rule {
  height: 1px;
  background: var(--color-divider);
  border: none;
}

.two-col {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: var(--space-16);
  align-items: center;
}
.two-col--reverse .two-col__media {
  order: 2;
}

.pull-quote {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 500;
  color: var(--color-text);
  border-left: 2px solid var(--color-primary);
  padding-left: var(--space-6);
  max-width: 56ch;
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}
.tag {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  padding: var(--space-1) var(--space-3);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  color: var(--color-text-muted);
}

/* Image framing */
.media-frame {
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--color-border);
}
.media-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.media-frame--wide img {
  aspect-ratio: 16 / 10;
}
.media-frame--tall img {
  aspect-ratio: 4 / 5;
}
.media-frame--square img {
  aspect-ratio: 1 / 1;
}

/* CTA band */
.cta-band {
  background: var(--color-surface-offset-2);
  color: var(--color-text);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: clamp(var(--space-10), 6vw, var(--space-16));
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-8);
  align-items: center;
  justify-content: space-between;
}
.cta-band h2,
.cta-band .h2 {
  color: var(--color-text);
  font-size: var(--text-xl);
  max-width: 32ch;
}
.cta-band p {
  color: var(--color-text-muted);
}

/* Roadmap / phases */
.phase-list {
  display: grid;
  gap: 0;
}
.phase {
  display: grid;
  grid-template-columns: 88px minmax(0, 1fr);
  gap: var(--space-8);
  padding-block: var(--space-8);
  border-top: 1px solid var(--color-divider);
  position: relative;
}
.phase:first-child {
  border-top: none;
}
.phase__num {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-primary);
  padding-top: var(--space-1);
}
.phase h4 {
  margin-bottom: var(--space-2);
}

/* Pillars */
.pillar-list {
  display: grid;
  gap: var(--space-10);
}
.pillar {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-4);
  padding-bottom: var(--space-10);
  border-bottom: 1px solid var(--color-divider);
}
.pillar:last-child {
  border-bottom: none;
  padding-bottom: 0;
}
.pillar__num {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  font-weight: 600;
  color: transparent;
  -webkit-text-stroke: 1.5px var(--color-primary);
  line-height: 1;
}

/* Table */
.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--text-sm);
}
.data-table th,
.data-table td {
  text-align: left;
  padding: var(--space-4);
  border-bottom: 1px solid var(--color-divider);
}
.data-table th {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-muted);
  font-weight: 500;
}

/* Forms */
.form-grid {
  display: grid;
  gap: var(--space-5);
}
.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-5);
}
.field {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}
.field label {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text);
}
.field input,
.field select,
.field textarea {
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: var(--space-3) var(--space-4);
  font-size: var(--text-base);
  color: var(--color-text);
}
.field input:focus,
.field select:focus,
.field textarea:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 1px;
  border-color: var(--color-primary);
}
.field textarea {
  resize: vertical;
  min-height: 120px;
}
.field--checkbox {
  flex-direction: row;
  align-items: flex-start;
  gap: var(--space-3);
}
.field--checkbox input {
  width: 20px;
  height: 20px;
  margin-top: 2px;
  accent-color: var(--color-primary);
}
.field--checkbox label {
  font-weight: 400;
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}
.form-note {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
}
.form-success {
  display: none;
  background: var(--color-success-highlight);
  border: 1px solid var(--color-success);
  color: var(--color-text);
  padding: var(--space-5);
  border-radius: var(--radius-sm);
  font-size: var(--text-sm);
}
.form-success--visible {
  display: block;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--color-divider);
  background: var(--color-surface-offset);
  padding-block: var(--space-16) var(--space-8);
}
.footer-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) repeat(3, minmax(0, 1fr));
  gap: var(--space-10);
  margin-bottom: var(--space-12);
}
.footer-brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-4);
  text-decoration: none;
  color: var(--color-text);
}
.footer-brand__mark {
  width: 32px;
  height: 32px;
}
.footer-brand__name {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: var(--text-sm);
  letter-spacing: 0.03em;
}
.footer-col h5 {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-faint);
  margin-bottom: var(--space-4);
}
.footer-col ul {
  display: grid;
  gap: var(--space-3);
}
.footer-col a {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  text-decoration: none;
}
.footer-col a:hover {
  color: var(--color-primary);
}
.footer-bottom {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-4);
  padding-top: var(--space-8);
  border-top: 1px solid var(--color-divider);
  font-size: var(--text-xs);
  color: var(--color-text-faint);
}

/* Skip link */
.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--color-primary);
  color: var(--color-text-inverse);
  padding: var(--space-3) var(--space-5);
  z-index: 200;
  border-radius: var(--radius-sm);
}
.skip-link:focus {
  left: var(--space-4);
  top: var(--space-4);
}

/* Use case grid on homepage */
.usecase-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: var(--space-6);
}

/* Ecosystem strip (About page) */
.ecosystem-strip {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  align-items: center;
}
.ecosystem-strip .tag {
  padding: var(--space-2) var(--space-4);
}

/* Content-visibility perf hint for long sections */
.lazy-section {
  content-visibility: auto;
  contain-intrinsic-size: 800px;
}

/* Scroll reveal */
[data-reveal] {
  opacity: 0;
  clip-path: inset(8% 0 0 0);
  transition:
    opacity 0.7s cubic-bezier(0.16, 1, 0.3, 1),
    clip-path 0.7s cubic-bezier(0.16, 1, 0.3, 1);
}
[data-reveal].is-visible {
  opacity: 1;
  clip-path: inset(0 0 0 0);
}

/* DAG dot pattern background accent */
.dag-accent {
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0.5;
  z-index: 0;
}

/* ==========================================================================
   Responsive
   ========================================================================== */
@media (max-width: 900px) {
  .page-hero__grid,
  .two-col {
    grid-template-columns: 1fr;
    gap: var(--space-10);
  }
  .two-col--reverse .two-col__media {
    order: 0;
  }
  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 720px) {
  .main-nav {
    position: fixed;
    top: 68px;
    left: 0;
    right: 0;
    bottom: 0;
    height: calc(100vh - 68px);
    z-index: 150;
    background: #0b0c0d;
    flex-direction: column;
    align-items: stretch;
    padding: var(--space-6);
    transform: translateX(100%);
    transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    overflow-y: auto;
  }
  .main-nav.is-open {
    transform: translateX(0);
  }
  .main-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: var(--space-1);
  }
  .main-nav a {
    padding: var(--space-4);
    font-size: var(--text-base);
    color: #ededed;
  }
  .main-nav a:hover,
  .main-nav a:focus-visible {
    color: #49eacb;
    background: rgba(73, 234, 203, 0.12);
  }
  .main-nav a[aria-current='page'] {
    color: #49eacb;
  }
  .nav-toggle {
    display: inline-flex;
  }
  .header-actions .btn--secondary {
    display: none;
  }
  .form-row {
    grid-template-columns: 1fr;
  }
  .footer-grid {
    grid-template-columns: 1fr;
    gap: var(--space-8);
  }
  .cta-band {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (max-width: 560px) {
  .phase {
    grid-template-columns: 1fr;
    gap: var(--space-3);
  }
}