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

html {
  font-size: 62.5%;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  font-size: 1.7rem;
  line-height: 1.65;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

img, video {
  max-width: 100%;
  height: auto;
  display: block;
}

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

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

ul, ol {
  list-style: none;
}

:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
}

.skip-link {
  position: absolute;
  top: -100%;
  left: var(--space-md);
  z-index: 10000;
  padding: var(--space-sm) var(--space-md);
  background: var(--color-accent);
  color: white;
  border-radius: var(--radius-sm);
  font-weight: 600;
}

.skip-link:focus {
  top: var(--space-md);
}

.container {
  width: min(92%, var(--container-max));
  margin-inline: auto;
}

.section {
  padding-block: var(--space-2xl);
}

.section--lg {
  padding-block: var(--space-3xl);
}

.section__label {
  font-family: var(--font-mono);
  font-size: 1.2rem;
  font-weight: 500;
  color: var(--color-accent);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  margin-bottom: var(--space-sm);
}

.section__title {
  font-size: clamp(2.8rem, 5vw, 4.2rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: var(--space-md);
}

.section__subtitle {
  font-size: 1.75rem;
  color: var(--color-text-muted);
  max-width: 65ch;
  line-height: 1.75;
  margin-bottom: var(--space-md);
}

.prose {
  max-width: 65ch;
}

.prose p {
  color: var(--color-text-muted);
  line-height: 1.75;
  margin-bottom: var(--space-md);
}

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

.reveal,
[data-motion="fade-up"] {
  opacity: 0;
  transform: translate3d(0, var(--motion-y), 0) scale(0.99);
  filter: blur(var(--motion-blur));
  transition:
    opacity var(--motion-duration) var(--motion-ease),
    transform var(--motion-duration) var(--motion-ease),
    filter var(--motion-duration) var(--motion-ease);
}

.reveal.is-visible,
[data-motion="fade-up"].is-visible {
  opacity: 1;
  transform: translate3d(0, 0, 0) scale(1);
  filter: blur(0);
}

.motion-line {
  display: block;
  opacity: 0;
  transform: translate3d(0, var(--motion-y), 0);
  filter: blur(var(--motion-blur));
  transition:
    opacity var(--motion-duration) var(--motion-ease),
    transform var(--motion-duration) var(--motion-ease),
    filter calc(var(--motion-duration) * 0.85) var(--motion-ease);
}

.motion-line.is-visible {
  opacity: 1;
  transform: translate3d(0, 0, 0);
  filter: blur(0);
}

[data-motion-stagger]:not(.is-visible) > *,
.motion-stagger:not(.is-visible) > * {
  opacity: 0;
  transform: translate3d(0, calc(var(--motion-y) * 0.75), 0) scale(0.98);
  filter: blur(calc(var(--motion-blur) * 0.6));
  transition:
    opacity var(--motion-duration) var(--motion-ease),
    transform var(--motion-duration) var(--motion-ease),
    filter var(--motion-duration) var(--motion-ease);
  transition-delay: var(--motion-stagger, 0ms);
}

[data-motion-stagger].is-visible > *,
.motion-stagger.is-visible > * {
  opacity: 1;
  transform: translate3d(0, 0, 0) scale(1);
  filter: blur(0);
}

.tag {
  display: inline-flex;
  align-items: center;
  padding: 0.4rem 1rem;
  font-family: var(--font-mono);
  font-size: 1.2rem;
  font-weight: 500;
  color: var(--color-text-muted);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  transition: border-color var(--transition-fast), color var(--transition-fast);
}

.tag:hover {
  border-color: var(--color-border-accent);
  color: var(--color-text);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  padding: 1.2rem 2rem;
  font-size: 1.4rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  transition: all var(--transition-base);
  white-space: nowrap;
}

.btn--primary {
  position: relative;
  overflow: hidden;
  isolation: isolate;
  background: var(--color-accent);
  color: white;
  box-shadow: 0 0 0 0 transparent;
  transition: background var(--transition-base), box-shadow var(--transition-base);
}

.btn--primary::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(
    105deg,
    transparent 35%,
    rgba(255, 255, 255, 0.18) 50%,
    transparent 65%
  );
  transform: translate3d(-120%, 0, 0);
  pointer-events: none;
}

.btn--primary:hover {
  background: var(--color-accent-hover);
  box-shadow: 0 0 20px var(--color-accent-glow), 0 0 40px rgba(99, 91, 255, 0.12);
}

.btn--primary:hover::after {
  animation: btn-glow-sweep 0.7s var(--motion-ease);
}

@keyframes btn-glow-sweep {
  to {
    transform: translate3d(120%, 0, 0);
  }
}

.btn--secondary {
  background: var(--color-surface);
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

.btn--secondary:hover {
  background: var(--color-surface-hover);
  border-color: var(--color-border-accent);
}

.btn--ghost {
  color: var(--color-text-muted);
  border: 1px solid transparent;
}

.btn--ghost:hover {
  color: var(--color-text);
  background: var(--color-surface);
}

.btn-group {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

@media (max-width: 767px) {
  :root {
    --motion-y: 24px;
    --motion-blur: 3px;
    --motion-duration: 520ms;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .reveal,
  [data-motion="fade-up"],
  .motion-line,
  [data-motion-stagger] > *,
  .motion-stagger > *,
  .timeline__item,
  .timeline::before,
  .leetcode-heatmap {
    opacity: 1;
    transform: none;
    filter: none;
    transition: none;
  }

  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}