/* ==========================================================================
   Srikar Samudrala — Portfolio
   Design tokens, light/dark themes, layout, components
   ========================================================================== */

/* ---------- Design tokens ---------- */
:root {
  --bg: #f7fafc;
  --surface: #ffffff;
  --surface-2: #eef4f8;
  --text: #10181f;
  --text-muted: #55636e;
  --accent: #0284c7;
  --accent-strong: #0369a1;
  --accent-soft: rgba(14, 165, 233, 0.12);
  --btn-bg: #7dd3fc;
  --btn-bg-hover: #38bdf8;
  --btn-text: #082f49;
  --glow: rgba(56, 189, 248, 0.16);
  --border: #e2eaf0;
  --shadow: 0 10px 30px rgba(16, 24, 31, 0.07);
  --shadow-lg: 0 18px 44px rgba(16, 24, 31, 0.13);
  --gradient: linear-gradient(92deg, #38bdf8 0%, #6366f1 100%);
  --header-bg: rgba(247, 250, 252, 0.82);
  --radius: 18px;
  --radius-sm: 12px;
  --header-h: 68px;
  --font: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-display: "Space Grotesk", "Inter", sans-serif;
}

[data-theme="dark"] {
  --bg: #0b1016;
  --surface: #131a22;
  --surface-2: #1a232d;
  --text: #eef4f8;
  --text-muted: #96a6b3;
  --accent: #7dd3fc;
  --accent-strong: #bae6fd;
  --accent-soft: rgba(125, 211, 252, 0.13);
  --btn-bg: #7dd3fc;
  --btn-bg-hover: #bae6fd;
  --btn-text: #082f49;
  --glow: rgba(56, 189, 248, 0.10);
  --border: #24303c;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.35);
  --shadow-lg: 0 18px 44px rgba(0, 0, 0, 0.5);
  --gradient: linear-gradient(92deg, #38bdf8 0%, #818cf8 100%);
  --header-bg: rgba(11, 16, 22, 0.82);
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  transition: background-color 0.3s ease, color 0.3s ease;
}

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

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  color: var(--accent-strong);
}

h1, h2, h3 {
  font-family: var(--font-display);
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin: 0 0 0.5em;
}

/* Cursor-following glow (sits behind all content) */
.cursor-glow {
  position: fixed;
  top: 0;
  left: 0;
  width: 680px;
  height: 680px;
  border-radius: 50%;
  background: radial-gradient(circle, var(--glow) 0%, transparent 62%);
  pointer-events: none;
  z-index: 0;
  transform: translate(-50%, -50%);
  will-change: transform;
}

main,
.site-footer {
  position: relative;
  z-index: 1;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

.container {
  width: min(1080px, 100% - 2.5rem);
  margin-inline: auto;
}

.accent {
  color: var(--accent);
  font-weight: 600;
}

/* ---------- Header / nav ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  height: var(--header-h);
  background: var(--header-bg);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
  transition: background-color 0.3s ease, border-color 0.3s ease;
}

.nav-wrap {
  height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--text);
}

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

.brand-logo {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  object-fit: cover;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  margin-left: auto;
}

.nav-link {
  padding: 0.45rem 0.9rem;
  border-radius: 999px;
  font-weight: 500;
  font-size: 0.95rem;
  color: var(--text-muted);
  transition: color 0.2s ease, background-color 0.2s ease;
}

.nav-link:hover {
  color: var(--text);
  background: var(--surface-2);
}

.nav-link.active {
  color: var(--accent);
  background: var(--accent-soft);
  font-weight: 600;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

/* Theme toggle */
.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
  transition: transform 0.2s ease, background-color 0.2s ease;
}

.theme-toggle:hover {
  transform: scale(1.06);
  background: var(--surface-2);
}

.theme-toggle svg {
  width: 19px;
  height: 19px;
}

.theme-toggle .icon-moon { display: block; }
.theme-toggle .icon-sun  { display: none; }

[data-theme="dark"] .theme-toggle .icon-moon { display: none; }
[data-theme="dark"] .theme-toggle .icon-sun  { display: block; }

/* Hamburger (mobile only) */
.menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  padding: 0 9px;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--surface);
  cursor: pointer;
}

.menu-toggle span {
  display: block;
  height: 2px;
  border-radius: 2px;
  background: var(--text);
  transition: transform 0.25s ease, opacity 0.25s ease;
}

.menu-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.menu-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}

.menu-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ---------- Hero ---------- */
.hero {
  min-height: calc(100svh - var(--header-h));
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 4rem 0 5rem;
  position: relative;
  overflow: hidden;
}

.hero-title {
  font-family: var(--font-display);
  font-size: clamp(2.4rem, 7vw, 4.5rem);
  font-weight: 800;
  margin: 0;
}

/* Rotating word — inline on desktop, its own line on mobile */
.rotator {
  display: inline-block;
  min-width: 1ch;
}

.rotator-word {
  display: inline-block;
  background: var(--gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  animation: word-in 0.55s cubic-bezier(0.22, 1, 0.36, 1);
  white-space: nowrap;
}

@keyframes word-in {
  from {
    opacity: 0;
    transform: translateY(0.45em);
    filter: blur(4px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
    filter: blur(0);
  }
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.6rem;
  margin-top: 2.5rem;
  padding: 0;
  list-style: none;
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.55rem 1.1rem;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface);
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text);
  transition: border-color 0.2s ease;
}

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

.hero-tag a {
  font-weight: 600;
}

.hero-scroll {
  margin-top: 3.5rem;
  color: var(--text-muted);
  font-size: 0.85rem;
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: 0.4rem;
}

.hero-scroll svg {
  width: 18px;
  height: 18px;
  animation: bob 1.8s ease-in-out infinite;
}

@keyframes bob {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(6px); }
}

/* ---------- Sections ---------- */
.section {
  padding: 4.5rem 0;
}

.section-head {
  margin-bottom: 2.75rem;
}

.section-head h2 {
  font-size: clamp(1.7rem, 4vw, 2.3rem);
  font-weight: 800;
}

.section-head p {
  color: var(--text-muted);
  margin: 0;
  max-width: 55ch;
}

/* ---------- Experience / project cards ---------- */
.xp-list {
  display: flex;
  flex-direction: column;
  gap: 1.75rem;
}

.xp-card {
  display: grid;
  grid-template-columns: 1.15fr 1fr;
  gap: 2.5rem;
  align-items: center;
  padding: 2.25rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--surface);
  box-shadow: var(--shadow);
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.xp-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.xp-card:nth-child(even) .xp-media {
  order: -1;
}

.xp-body h3 {
  font-size: 1.45rem;
  font-weight: 700;
  margin-bottom: 0.35rem;
}

.xp-role {
  color: var(--accent);
  font-weight: 600;
  margin: 0 0 0.2rem;
}

.xp-dates {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin: 0 0 1rem;
}

.xp-desc {
  color: var(--text-muted);
  margin: 0 0 1.4rem;
}

.badge {
  display: inline-block;
  padding: 0.2rem 0.7rem;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  margin-bottom: 0.8rem;
}

.xp-media {
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.xp-media img {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  transition: transform 0.35s ease;
}

.xp-card:hover .xp-media img {
  transform: scale(1.04);
}

.xp-media-brand {
  aspect-ratio: 16 / 10;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--gradient);
}

.xp-media-brand span {
  font-family: var(--font-display);
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: #fff;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.7rem 1.5rem;
  border-radius: 999px;
  border: none;
  background: var(--btn-bg);
  color: var(--btn-text);
  font-family: var(--font);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background-color 0.2s ease;
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px var(--accent-soft);
  background: var(--btn-bg-hover);
  color: var(--btn-text);
}

.btn-outline {
  background: transparent;
  border: 1.5px solid var(--accent);
  color: var(--accent);
}

.btn-outline:hover {
  background: var(--accent-soft);
  color: var(--accent);
  box-shadow: none;
}

/* ---------- About page ---------- */
.about-intro {
  display: grid;
  grid-template-columns: 340px 1fr;
  gap: 3rem;
  align-items: start;
  padding-top: 4rem;
}

.about-photo img {
  width: 100%;
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
}

.about-copy h1 {
  font-size: clamp(1.9rem, 4.5vw, 2.6rem);
  font-weight: 800;
}

.about-copy p {
  color: var(--text-muted);
}

.about-links {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-top: 1.75rem;
  flex-wrap: wrap;
}

.social-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  transition: transform 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.social-icon:hover {
  transform: translateY(-3px);
  color: var(--accent);
  border-color: var(--accent);
}

.social-icon svg {
  width: 20px;
  height: 20px;
}

/* Skills */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.5rem;
}

.skill-card {
  padding: 1.75rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--surface);
  box-shadow: var(--shadow);
}

.skill-card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--accent);
}

.skill-card ul {
  margin: 0;
  padding: 0;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* ---------- Experience detail pages ---------- */
.detail-hero {
  text-align: center;
  padding: 4rem 0 2.5rem;
}

.detail-hero h1 {
  font-size: clamp(2.2rem, 5.5vw, 3.4rem);
  font-weight: 800;
}

.detail-hero .subtitle {
  color: var(--text-muted);
  font-size: 1.1rem;
  max-width: 60ch;
  margin: 0 auto;
}

.detail-cover {
  margin: 2rem auto 0;
  max-width: 760px;
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}

.detail-section {
  max-width: 760px;
  margin: 0 auto;
  padding: 2.5rem 0;
}

.detail-section h2 {
  font-size: 1.6rem;
  font-weight: 800;
}

.detail-section p {
  color: var(--text-muted);
}

.gallery {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
}

.gallery img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow);
  transition: transform 0.25s ease;
}

.gallery img:hover {
  transform: scale(1.02);
}

.detail-back {
  text-align: center;
  padding: 1rem 0 4rem;
}

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 2rem 0;
  margin-top: 3rem;
}

.footer-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

.footer-wrap p {
  margin: 0;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.footer-links {
  display: flex;
  gap: 1.25rem;
}

.footer-links a {
  color: var(--text-muted);
  font-size: 0.9rem;
  font-weight: 500;
}

.footer-links a:hover {
  color: var(--accent);
}

/* ---------- Scroll reveal ---------- */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .rotator-word,
  .hero-scroll svg {
    animation: none;
  }
}

/* ==========================================================================
   Responsive
   ========================================================================== */
@media (max-width: 860px) {
  .about-intro {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .about-photo {
    max-width: 320px;
    margin-inline: auto;
  }

  .xp-card {
    grid-template-columns: 1fr;
    gap: 1.5rem;
    padding: 1.5rem;
  }

  .xp-card:nth-child(even) .xp-media {
    order: 0;
  }

  .xp-media {
    order: -1;
  }
}

@media (max-width: 720px) {
  /* Mobile nav: dropdown panel under header */
  .menu-toggle {
    display: flex;
  }

  .site-nav {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0.25rem;
    padding: 1rem 1.25rem 1.25rem;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-lg);
    transform: translateY(-12px);
    opacity: 0;
    visibility: hidden;
    transition: transform 0.25s ease, opacity 0.25s ease, visibility 0.25s;
  }

  .site-nav.open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav-link {
    padding: 0.8rem 1rem;
    font-size: 1.05rem;
    border-radius: var(--radius-sm);
  }
}

@media (max-width: 640px) {
  .hero {
    padding: 3rem 0 4rem;
  }

  /* The color-changing word gets its own line on mobile */
  .rotator {
    display: block;
    margin-top: 0.3em;
  }

  .hero-title {
    font-size: clamp(2.1rem, 10vw, 2.8rem);
  }

  .hero-tags {
    flex-direction: column;
    align-items: center;
  }

  .hero-tag {
    width: 100%;
    max-width: 340px;
    justify-content: center;
  }

  .section {
    padding: 3rem 0;
  }

  .gallery {
    grid-template-columns: 1fr;
  }

  .footer-wrap {
    flex-direction: column;
    text-align: center;
  }
}