:root {
  --bg: #050505;
  --surface: rgba(13, 13, 13, 0.92);
  --surface-strong: #121212;
  --border: #222;
  --border-strong: #333;
  --text: #f0f0f0;
  --muted: #8e8e8e;
  --soft: #666;
  --accent: #ffffff;
  --accent-soft: rgba(255, 255, 255, 0.06);
}

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

html {
  color-scheme: dark;
}

body {
  align-items: center;
  background:
    radial-gradient(circle at top, rgba(255, 255, 255, 0.035), transparent 42%),
    linear-gradient(180deg, #060606 0%, #020202 100%);
  color: var(--text);
  display: flex;
  font-family: "Inter", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  justify-content: center;
  min-height: 100vh;
  min-height: 100dvh;
  overflow-x: hidden;
  padding: 24px;
  position: relative;
}

body::before {
  background: radial-gradient(circle, rgba(255, 255, 255, 0.04) 0%, transparent 70%);
  content: "";
  height: min(720px, 90vw);
  left: 50%;
  pointer-events: none;
  position: absolute;
  top: 50%;
  transform: translate(-50%, -50%);
  width: min(720px, 90vw);
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

button {
  border: 0;
}

.shell {
  position: relative;
  width: min(100%, 760px);
  z-index: 1;
}

.view {
  width: 100%;
}

.hero {
  margin: 0 auto;
  max-width: 620px;
  padding: 24px 12px;
  text-align: center;
}

.brand {
  font-family: "Space Mono", monospace;
  font-size: clamp(3rem, 10vw, 6rem);
  font-weight: 700;
  letter-spacing: -0.04em;
  line-height: 1;
  margin-bottom: 1.25rem;
}

.brand .null {
  color: #ffffff;
}

.brand .zair {
  color: #5a5a5a;
}

.brand .dot {
  color: #333333;
  font-weight: 400;
}

.tagline {
  color: var(--soft);
  font-size: clamp(0.95rem, 2.5vw, 1.15rem);
  font-weight: 300;
  letter-spacing: 0.06em;
  margin-bottom: 2.5rem;
  text-transform: uppercase;
}

.divider {
  background: var(--border-strong);
  height: 1px;
  margin: 0 auto 2.5rem;
  width: 40px;
}

.email {
  border: 1px solid var(--border);
  border-radius: 6px;
  color: #9a9a9a;
  display: inline-block;
  font-family: "Space Mono", monospace;
  font-size: clamp(0.85rem, 2vw, 1rem);
  padding: 0.6em 1.4em;
  text-decoration: none;
  transition:
    background 0.25s ease,
    border-color 0.25s ease,
    color 0.25s ease;
}

.email:hover,
.email:focus-visible {
  background: rgba(255, 255, 255, 0.04);
  border-color: #555;
  color: #ffffff;
  outline: none;
}

.game-toggle {
  background: none;
  color: #3a3a3a;
  cursor: pointer;
  display: block;
  font-family: "Space Mono", monospace;
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  margin: 2rem auto 0;
  text-transform: uppercase;
  transition: color 0.25s ease;
}

.game-toggle:hover,
.game-toggle:focus-visible {
  color: #6c6c6c;
  outline: none;
}

.game-wrap {
  align-items: center;
  display: none;
  flex-direction: column;
  gap: 1rem;
  margin-top: 1.5rem;
}

.game-wrap.active {
  display: flex;
}

.math-stats,
.math-feedback,
.math-question,
.math-options button {
  font-family: "Space Mono", monospace;
}

.math-stats {
  color: #4a4a4a;
  display: flex;
  font-size: 0.8rem;
  gap: 1.5rem;
}

.math-question {
  color: #cccccc;
  font-size: clamp(1.8rem, 5vw, 2.5rem);
  letter-spacing: 0.02em;
}

.math-options {
  display: grid;
  gap: 10px;
  grid-template-columns: 1fr 1fr;
  max-width: 280px;
  width: 100%;
}

.math-options button {
  background: #0f0f0f;
  border: 1px solid #1a1a1a;
  border-radius: 6px;
  color: #888888;
  cursor: pointer;
  font-size: 1.1rem;
  padding: 0.7em 1em;
  transition:
    background 0.2s ease,
    border-color 0.2s ease,
    color 0.2s ease;
}

.math-options button:hover,
.math-options button:focus-visible {
  background: #151515;
  border-color: #444444;
  color: #ffffff;
  outline: none;
}

.math-options button:disabled {
  cursor: default;
}

.math-options button.correct {
  background: #101a10;
  border-color: #2a5a2a;
  color: #78b878;
}

.math-options button.wrong {
  background: #1a1010;
  border-color: #5a2a2a;
  color: #c07b7b;
}

.math-feedback {
  color: #4a4a4a;
  font-size: 0.85rem;
  height: 1.2em;
}

.math-timer {
  background: #111111;
  border-radius: 2px;
  height: 3px;
  max-width: 280px;
  overflow: hidden;
  width: 100%;
}

.math-timer-bar {
  background: #333333;
  border-radius: 2px;
  height: 100%;
  transition: width 0.1s linear;
  width: 100%;
}

.link-view {
  margin: 0 auto;
  max-width: 560px;
}

.link-card {
  background: linear-gradient(180deg, rgba(18, 18, 18, 0.96), rgba(9, 9, 9, 0.96));
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 24px;
  box-shadow: 0 24px 80px rgba(0, 0, 0, 0.4);
  padding: clamp(24px, 4vw, 36px);
}

.eyebrow {
  color: var(--muted);
  font-family: "Space Mono", monospace;
  font-size: 0.78rem;
  letter-spacing: 0.14em;
  margin-bottom: 1rem;
  text-transform: uppercase;
}

.link-title {
  font-size: clamp(2rem, 5vw, 3.15rem);
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 0.96;
  max-width: 10ch;
}

.link-copy {
  color: #bcbcbc;
  font-size: 1rem;
  line-height: 1.6;
  margin-top: 1rem;
}

.link-meta {
  align-items: center;
  background: var(--accent-soft);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 14px;
  display: flex;
  gap: 12px;
  justify-content: space-between;
  margin-top: 1.5rem;
  padding: 14px 16px;
}

.meta-label {
  color: var(--muted);
  font-size: 0.92rem;
}

.meta-value {
  color: #ffffff;
  font-family: "Space Mono", monospace;
  font-size: 0.95rem;
  overflow-wrap: anywhere;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 1.5rem;
}

.action {
  align-items: center;
  border: 1px solid transparent;
  border-radius: 999px;
  color: #ffffff;
  cursor: pointer;
  display: inline-flex;
  font-size: 0.95rem;
  font-weight: 600;
  justify-content: center;
  min-height: 46px;
  padding: 0 18px;
  text-decoration: none;
  transition:
    background 0.2s ease,
    border-color 0.2s ease,
    color 0.2s ease,
    transform 0.2s ease;
}

.action:hover,
.action:focus-visible {
  outline: none;
  transform: translateY(-1px);
}

.action.primary {
  background: #ffffff;
  color: #050505;
}

.action.primary:hover,
.action.primary:focus-visible {
  background: #e9e9e9;
}

.action.secondary,
.action.ghost {
  background: transparent;
  border-color: rgba(255, 255, 255, 0.12);
}

.action.secondary:hover,
.action.secondary:focus-visible,
.action.ghost:hover,
.action.ghost:focus-visible {
  background: rgba(255, 255, 255, 0.06);
  border-color: rgba(255, 255, 255, 0.2);
}

.link-note {
  color: var(--soft);
  font-size: 0.92rem;
  line-height: 1.6;
  margin-top: 1.25rem;
}

[hidden] {
  display: none !important;
}

@media (max-width: 640px) {
  body {
    padding: 18px;
  }

  .hero {
    padding: 12px 6px;
  }

  .tagline {
    letter-spacing: 0.03em;
    margin-bottom: 2rem;
  }

  .divider {
    margin-bottom: 2rem;
  }

  .actions {
    flex-direction: column;
  }

  .action {
    width: 100%;
  }

  .link-meta {
    align-items: flex-start;
    flex-direction: column;
  }
}