/*
  404-07 — Dark Terminal / Route Error, standalone HTML/CSS implementation.
  No build step, no framework, no external dependency: copy this file and
  index.html into any project and open it as-is.
*/

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

:root {
  --brand: #39ff14;
  --brand-foreground: #0a0a0b;
  --bg: #0a0a0b;
  --white: #ffffff;
  --border: rgba(255, 255, 255, 0.1);
  --border-soft: rgba(255, 255, 255, 0.15);
  --surface: rgba(255, 255, 255, 0.03);
  --text-muted: #a3a3a3;
  --text-dim: #737373;
  --terminal-text: #d4d4d4;
  --font-sans:
    -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji",
    "Segoe UI Emoji";
  --font-mono:
    ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--white);
  background-color: var(--bg);
  line-height: 1.5;
}

a {
  text-decoration: none;
  color: inherit;
}

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

.notfound {
  background-color: var(--bg);
}

/* Motion — disabled entirely under reduced motion; every element already
   renders at its final, fully visible state outside this media query, and
   the terminal cursor sits fully opaque (static, non-blinking). */
@media (prefers-reduced-motion: no-preference) {
  @keyframes al-up {
    from {
      opacity: 0;
      transform: translateY(14px);
    }
    to {
      opacity: 1;
      transform: translateY(0);
    }
  }

  @keyframes al-line-in {
    from {
      opacity: 0;
      transform: translateY(4px);
    }
    to {
      opacity: 1;
      transform: translateY(0);
    }
  }

  @keyframes al-blink {
    0%,
    45% {
      opacity: 1;
    }
    50%,
    95% {
      opacity: 0;
    }
    100% {
      opacity: 1;
    }
  }

  .eyebrow,
  .heading,
  .description,
  .actions,
  .terminal {
    animation: al-up 650ms cubic-bezier(0.16, 1, 0.3, 1) both;
  }

  .eyebrow {
    animation-delay: 60ms;
  }
  .heading {
    animation-delay: 140ms;
  }
  .description {
    animation-delay: 220ms;
  }
  .actions {
    animation-delay: 300ms;
  }
  .terminal {
    animation-delay: 200ms;
  }

  .line {
    animation: al-line-in 380ms cubic-bezier(0.16, 1, 0.3, 1) both;
  }

  .cursor {
    animation: al-blink 1100ms steps(1, end) infinite;
  }
}

/* Introduction */
.intro {
  width: 100%;
  max-width: 72rem;
  margin: 0 auto;
  padding: clamp(4rem, 3rem + 3vw, 7rem) clamp(1rem, 0.3rem + 3vw, 2rem);
}

.intro__grid {
  display: grid;
  grid-template-columns: 1fr;
  align-items: center;
  gap: 3rem;
}

.intro__content {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  text-align: left;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  border-radius: 999px;
  border: 1px solid var(--border);
  background-color: var(--surface);
  color: var(--brand);
  padding: 0.25rem 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.02em;
}

.heading {
  margin: 1.5rem 0 0;
  font-weight: 600;
  font-size: clamp(2rem, 1.5rem + 2.4vw, 3.25rem);
  line-height: 1.1;
  letter-spacing: -0.01em;
  color: var(--white);
}

.description {
  margin: 1.25rem 0 0;
  max-width: 28rem;
  font-size: clamp(1rem, 0.94rem + 0.3vw, 1.125rem);
  line-height: 1.65;
  color: var(--text-muted);
}

.actions {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  width: 100%;
  margin-top: 2.25rem;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  padding: 0.875rem 1.5rem;
  font-size: 0.875rem;
  font-weight: 600;
  transition:
    background-color 150ms ease,
    border-color 150ms ease,
    opacity 150ms ease;
}

.button--primary {
  color: var(--brand-foreground);
  background-color: var(--brand);
}

.button--primary:hover {
  opacity: 0.9;
}

.button--secondary {
  color: var(--white);
  background-color: transparent;
  border: 1px solid var(--border-soft);
}

.button--secondary:hover {
  background-color: rgba(255, 255, 255, 0.05);
}

.eyebrow:focus-visible,
.button:focus-visible {
  outline: 2px solid var(--brand);
  outline-offset: 2px;
}

/* Terminal — decorative flavor panel, `aria-hidden` in the markup. */
.terminal__panel {
  border-radius: 1rem;
  overflow: hidden;
  border: 1px solid var(--border);
  background-color: var(--surface);
  box-shadow: 0 24px 48px -24px rgba(0, 0, 0, 0.6);
}

.terminal__chrome {
  display: flex;
  align-items: center;
  gap: 0.375rem;
  padding: 0.75rem 1.25rem;
  border-bottom: 1px solid var(--border);
}

.dot {
  width: 0.625rem;
  height: 0.625rem;
  border-radius: 50%;
  background-color: rgba(255, 255, 255, 0.2);
}

.terminal__label {
  margin-left: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  color: var(--text-dim);
}

.terminal__body {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  padding: 1.5rem 1.25rem;
  font-family: var(--font-mono);
  font-size: 0.9375rem;
  color: var(--terminal-text);
}

.cursor {
  display: inline-block;
  width: 0.5rem;
  height: 1rem;
  transform: translateY(2px);
  background-color: var(--brand);
  opacity: 1;
}

/* Structural breakpoints */
@media (min-width: 640px) {
  .actions {
    flex-direction: row;
    width: auto;
  }
}

@media (min-width: 1024px) {
  .intro__grid {
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
  }
}
404 07

Requirements

Dependencies

Usage
