/* ==========================================================================
   0. CUSTOM PROPERTIES
   ========================================================================== */

:root {
  --c-bg: #0a0a0a;
  --c-surface: #131313;
  --c-border: #1e1e1e;
  --c-text: #d8d4cf;
  --c-text-muted: #7a7672;
  --c-text-faint: #4a4845;
  --c-award: #c9a96e;

  --f-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  --f-family-serif: 'Lora', Georgia, 'Times New Roman', serif;
  --f-size-xs: 0.75rem;
  --f-size-sm: 0.8125rem;
  --f-size-base: 0.9375rem;
  --f-size-lg: 1.125rem;
  --f-size-xl: 1.375rem;
  --f-size-2xl: 2rem;
  --f-size-3xl: 2.75rem;

  --s-xs: 0.25rem;
  --s-sm: 0.5rem;
  --s-md: 1rem;
  --s-lg: 1.5rem;
  --s-xl: 2rem;
  --s-2xl: 3rem;
  --s-3xl: 4.5rem;

  --timeline-width: 1px;
  --card-radius: 6px;
  --dot-size: 9px;

  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --duration: 0.25s;
  --duration-long: 0.5s;
}

/* ==========================================================================
   1. RESET & BASE
   ========================================================================== */

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

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  background: var(--c-bg);
  color: var(--c-text);
  font-family: var(--f-family);
  font-size: var(--f-size-base);
  line-height: 1.65;
  min-height: 100vh;
}

img {
  max-width: 100%;
  display: block;
}

a {
  color: var(--c-text);
  text-decoration: none;
  transition: color var(--duration) var(--ease-out);
}

a:hover {
  color: var(--c-text-muted);
}

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

/* ==========================================================================
   2. TYPOGRAPHY
   ========================================================================== */

h1, h2, h3 {
  font-family: var(--f-family-serif);
  line-height: 1.25;
  font-weight: 500;
  color: var(--c-text);
}

/* ==========================================================================
   3. HERO
   ========================================================================== */

.hero {
  position: relative;
  text-align: center;
  padding: 5rem var(--s-lg) 3.5rem;
  border-bottom: 1px solid var(--c-border);
}

.hero__title {
  font-size: var(--f-size-2xl);
  font-weight: 400;
  letter-spacing: -0.01em;
  margin-bottom: var(--s-sm);
  color: var(--c-text);
}

.hero__subtitle {
  font-family: var(--f-family-serif);
  font-style: italic;
  color: var(--c-text-muted);
  font-size: var(--f-size-base);
  font-weight: 400;
  margin-bottom: var(--s-2xl);
}

/* GitHub profile card */
#github-profile {
  position: fixed;
  top: var(--s-lg);
  right: var(--s-lg);
  z-index: 100;
}

.github-card {
  display: inline-flex;
  align-items: center;
  gap: 0;
  padding: var(--s-xs);
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: 999px;
  transition: gap var(--duration) var(--ease-out),
              padding var(--duration) var(--ease-out),
              border-color var(--duration) var(--ease-out);
}

.github-card:hover {
  gap: var(--s-md);
  padding: var(--s-sm) var(--s-lg) var(--s-sm) var(--s-sm);
  border-color: var(--c-text-faint);
  color: var(--c-text);
}

.github-card__avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  flex-shrink: 0;
}

.github-card__info {
  display: flex;
  flex-direction: column;
  text-align: left;
  line-height: 1.3;
  max-width: 0;
  opacity: 0;
  overflow: hidden;
  white-space: nowrap;
  transition: max-width var(--duration) var(--ease-out),
              opacity var(--duration) var(--ease-out);
}

.github-card:hover .github-card__info {
  max-width: 200px;
  opacity: 1;
}

.github-card__name {
  font-size: var(--f-size-sm);
  font-weight: 500;
  color: var(--c-text);
}

.github-card__username {
  font-size: var(--f-size-xs);
  color: var(--c-text-muted);
}

.hero__stats {
  display: flex;
  justify-content: center;
  gap: var(--s-2xl);
  flex-wrap: wrap;
}

.stat {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
}

.stat__number {
  font-family: var(--f-family-serif);
  font-size: var(--f-size-xl);
  font-weight: 400;
  color: var(--c-text);
}

.stat__label {
  font-size: var(--f-size-xs);
  color: var(--c-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

/* ==========================================================================
   3b. SKILLS CAROUSEL
   ========================================================================== */

.skills-carousel {
  position: relative;
  overflow: hidden;
  margin-top: var(--s-2xl);
  padding: var(--s-md) 0;
  mask-image: linear-gradient(
    to right,
    transparent,
    black 12%,
    black 88%,
    transparent
  );
  -webkit-mask-image: linear-gradient(
    to right,
    transparent,
    black 12%,
    black 88%,
    transparent
  );
}

.skills-carousel__track {
  display: flex;
  gap: var(--s-lg);
  width: max-content;
  animation: carousel-scroll 120s linear infinite;
}

.skills-carousel__track:hover {
  animation-play-state: paused;
}

.skills-carousel__item {
  font-size: var(--f-size-xs);
  color: var(--c-text-faint);
  white-space: nowrap;
  flex-shrink: 0;
  letter-spacing: 0.03em;
}

.skills-carousel__item + .skills-carousel__item::before {
  content: "\00b7";
  margin-right: var(--s-lg);
  color: var(--c-text-faint);
}

@keyframes carousel-scroll {
  0% {
    transform: translateX(0);
  }
  100% {
    transform: translateX(-50%);
  }
}

@media (prefers-reduced-motion: reduce) {
  .skills-carousel__track {
    animation: none;
    flex-wrap: wrap;
    justify-content: center;
    width: auto;
    gap: var(--s-sm);
  }

  .skills-carousel {
    mask-image: none;
    -webkit-mask-image: none;
  }
}

/* ==========================================================================
   4. TIMELINE LOGO (opposite side)
   ========================================================================== */

.timeline__logo {
  display: none;
}

/* ==========================================================================
   5. TIMELINE STRUCTURE
   ========================================================================== */

.timeline {
  position: relative;
  max-width: 1100px;
  margin: 0 auto;
  padding: var(--s-2xl) var(--s-lg);
}

.timeline__line {
  position: absolute;
  left: 16px;
  top: 0;
  bottom: 0;
  width: var(--timeline-width);
  background: var(--c-border);
}

.timeline__entry {
  position: relative;
  margin-bottom: var(--s-2xl);
  padding-left: 44px;
  opacity: 0;
  transform: translateY(20px);
  transition: opacity var(--duration-long) var(--ease-out),
              transform var(--duration-long) var(--ease-out);
  transition-delay: var(--delay, 0ms);
}

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

.timeline__dot {
  position: absolute;
  left: calc(16px - var(--dot-size) / 2 + var(--timeline-width) / 2);
  top: 28px;
  width: var(--dot-size);
  height: var(--dot-size);
  border-radius: 50%;
  background: var(--c-text-faint);
  z-index: 1;
}

.timeline__empty {
  text-align: center;
  color: var(--c-text-muted);
  padding: var(--s-3xl) 0;
  font-size: var(--f-size-base);
  font-family: var(--f-family-serif);
  font-style: italic;
}

/* Year dividers */
.timeline__year {
  position: relative;
  padding-left: 44px;
  margin-bottom: var(--s-lg);
  margin-top: var(--s-md);
}

.timeline__year:first-child {
  margin-top: 0;
}

.timeline__year-label {
  font-family: var(--f-family-serif);
  font-size: var(--f-size-sm);
  font-weight: 400;
  color: var(--c-text-faint);
  letter-spacing: 0.05em;
}

/* ==========================================================================
   6. TIMELINE CARDS
   ========================================================================== */

.timeline__card {
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--card-radius);
  overflow: hidden;
  transition: border-color var(--duration) var(--ease-out);
}

.timeline__card:hover {
  border-color: var(--c-text-faint);
}

.timeline__thumb {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border-bottom: 1px solid var(--c-border);
}

.timeline__body {
  padding: var(--s-lg) var(--s-xl);
}

.timeline__header {
  margin-bottom: var(--s-md);
}

.timeline__dateline {
  font-size: var(--f-size-xs);
  color: var(--c-text-faint);
  letter-spacing: 0.04em;
  margin-bottom: 6px;
}

.timeline__dateline time {
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.timeline__title {
  font-size: var(--f-size-xl);
  font-weight: 500;
  letter-spacing: -0.01em;
  margin-bottom: 2px;
}

.timeline__hackathon {
  font-size: var(--f-size-sm);
  color: var(--c-text-muted);
}

.timeline__desc {
  font-size: var(--f-size-sm);
  color: var(--c-text-muted);
  line-height: 1.7;
  margin-bottom: var(--s-md);
}

/* ==========================================================================
   7. COMPONENTS
   ========================================================================== */

/* Tags -- inline text with dot separators */
.timeline__tags {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0;
  margin-bottom: var(--s-md);
  font-size: var(--f-size-xs);
  color: var(--c-text-faint);
}

.tag {
  white-space: nowrap;
}

.tag + .tag::before {
  content: "\00b7";
  margin: 0 0.5em;
  color: var(--c-text-faint);
}

/* Meta (team size, award) */
.timeline__meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-md);
  align-items: center;
  margin-bottom: var(--s-md);
  font-size: var(--f-size-xs);
  color: var(--c-text-muted);
}

.timeline__team,
.timeline__award {
  display: inline-flex;
  align-items: center;
  gap: var(--s-xs);
}

.timeline__award {
  color: var(--c-award);
}

/* Links */
.timeline__links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-sm);
  padding-top: var(--s-sm);
  border-top: 1px solid var(--c-border);
}

.timeline__link {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 6px 10px;
  font-size: var(--f-size-xs);
  font-weight: 500;
  color: var(--c-text-muted);
  border-radius: 4px;
  transition: color var(--duration) var(--ease-out);
}

.timeline__link:hover {
  color: var(--c-text);
}

.timeline__link svg {
  opacity: 0.5;
}

.timeline__link:hover svg {
  opacity: 0.8;
}

/* ==========================================================================
   8. FOOTER
   ========================================================================== */

.footer {
  text-align: center;
  padding: var(--s-3xl) var(--s-md) var(--s-2xl);
  color: var(--c-text-faint);
  font-size: var(--f-size-xs);
  letter-spacing: 0.03em;
}

/* ==========================================================================
   9. ANIMATIONS
   ========================================================================== */

@media (prefers-reduced-motion: reduce) {
  .timeline__entry {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .timeline__card {
    transition: none;
  }

  html {
    scroll-behavior: auto;
  }
}

/* ==========================================================================
   10. RESPONSIVE
   ========================================================================== */

@media (min-width: 768px) {
  .hero__title {
    font-size: var(--f-size-3xl);
  }

  .hero {
    padding: 6rem var(--s-xl) 4rem;
  }

  .timeline {
    padding: var(--s-3xl) var(--s-xl);
  }

  .timeline__line {
    left: 50%;
    transform: translateX(-50%);
  }

  .timeline__entry {
    display: grid;
    grid-template-columns: 1fr var(--dot-size) 1fr;
    gap: 0 var(--s-xl);
    align-items: start;
    padding-left: 0;
    width: 100%;
  }

  .timeline__dot {
    position: static;
    grid-column: 2;
    grid-row: 1;
    justify-self: center;
    margin-top: 28px;
  }

  .timeline__logo {
    display: flex;
    align-items: center;
    justify-content: center;
  }

  .timeline__logo img {
    max-width: 120px;
    max-height: 80px;
    object-fit: contain;
    opacity: 0.5;
    transition: opacity var(--duration) var(--ease-out);
  }

  .timeline__entry:hover .timeline__logo img {
    opacity: 0.8;
  }

  /* Left card: card | dot | logo */
  .timeline__entry--left .timeline__card {
    grid-column: 1;
    grid-row: 1;
  }

  .timeline__entry--left .timeline__body {
    text-align: right;
  }

  .timeline__entry--left .timeline__tags,
  .timeline__entry--left .timeline__links,
  .timeline__entry--left .timeline__meta {
    justify-content: flex-end;
  }

  .timeline__entry--left .timeline__logo {
    grid-column: 3;
    grid-row: 1;
  }

  /* Right card: logo | dot | card */
  .timeline__entry--right .timeline__logo {
    grid-column: 1;
    grid-row: 1;
  }

  .timeline__entry--right .timeline__card {
    grid-column: 3;
    grid-row: 1;
  }

  /* Year dividers */
  .timeline__year {
    text-align: center;
    padding-left: 0;
  }

  /* Animation direction */
  .timeline__entry--left {
    transform: translateX(-15px);
  }

  .timeline__entry--right {
    transform: translateX(15px);
  }

  .timeline__entry.is-visible {
    opacity: 1;
    transform: translateX(0) translateY(0);
  }
}

@media (min-width: 1024px) {
  .hero__title {
    font-size: 3.25rem;
  }
}