/* ========================================================
   RETHIKA RAVINDRAN — PORTFOLIO
   Design tokens: near-black "vacuum" background, sodium-D
   flare amber accent (a nod to spectroscopy), spectral-line
   motif used as the signature visual element throughout.
   ======================================================== */

:root {
  --bg: #0a0b0e;
  --surface: #131519;
  --surface-2: #1b1e24;
  --line: rgba(255, 255, 255, 0.08);
  --line-strong: rgba(255, 255, 255, 0.14);
  --text: #edeef0;
  --text-dim: #9ba0a8;
  --text-faint: #676c74;
  --accent: #ffb833;
  --accent-soft: rgba(255, 184, 51, 0.14);
  --accent-line: rgba(255, 184, 51, 0.4);

  --font-display: "Space Grotesk", "Segoe UI", sans-serif;
  --font-body: "Inter", "Segoe UI", sans-serif;
  --font-mono: ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;

  --max-w: 1180px;
  --radius: 14px;
}

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

html {
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  * {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  line-height: 1.6;
  font-size: 16px;
  overflow-x: hidden;
}

/* subtle vertical spectral wash behind everything */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(ellipse 60% 40% at 80% -10%, rgba(255, 184, 51, 0.08), transparent 60%),
    radial-gradient(ellipse 50% 30% at 10% 0%, rgba(255, 184, 51, 0.04), transparent 60%);
}

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

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

ul {
  list-style: none;
}

.container {
  max-width: var(--max-w);
  margin-inline: auto;
  padding-inline: 24px;
}

section {
  padding: 96px 0;
  border-bottom: 1px solid var(--line);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 18px;
}

.eyebrow::before {
  content: "";
  width: 22px;
  height: 1px;
  background: var(--accent);
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  line-height: 1.1;
  letter-spacing: -0.01em;
}

h2 {
  font-size: clamp(1.9rem, 3.2vw, 2.6rem);
  font-weight: 600;
}

.section-head {
  max-width: 640px;
  margin-bottom: 56px;
}

.section-head p {
  color: var(--text-dim);
  margin-top: 14px;
  font-size: 1.05rem;
}

::selection {
  background: var(--accent);
  color: #100b00;
}

/* focus visibility */
a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------------- Navbar ---------------- */

.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 20px 0;
  transition: padding 0.3s ease, background 0.3s ease, border-color 0.3s ease;
  border-bottom: 1px solid transparent;
}

.navbar.scrolled {
  padding: 12px 0;
  background: rgba(10, 11, 14, 0.85);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.05rem;
}

.brand-mark {
  width: 34px;
  height: 34px;
  border-radius: 8px;
  background: var(--surface-2);
  border: 1px solid var(--line-strong);
  display: flex;
  align-items: center;
  justify-content: center;
}

.brand-mark svg { width: 18px; height: 18px; }

.nav-links {
  display: flex;
  align-items: center;
  gap: 36px;
}

.nav-links a {
  font-size: 0.92rem;
  color: var(--text-dim);
  position: relative;
  padding: 4px 0;
  transition: color 0.2s ease;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text);
}

.nav-links a.active::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -2px;
  width: 100%;
  height: 2px;
  background: var(--accent);
}

.nav-cta {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--accent);
  color: #16120a;
  font-weight: 600;
  font-size: 0.88rem;
  padding: 9px 18px;
  border-radius: 999px;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.nav-cta:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(255, 184, 51, 0.25);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
}

.nav-toggle span {
  width: 22px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: transform 0.25s ease, opacity 0.25s ease;
}

/* ---------------- Hero ---------------- */

.hero {
  position: relative;
  padding: 180px 0 120px;
  border-bottom: 1px solid var(--line);
  overflow: hidden;
}

.hero .container {
  display: block;
  max-width: 760px;
}

.hero-name {
  font-size: clamp(2.6rem, 6vw, 4.4rem);
  font-weight: 700;
}

.hero-role {
  font-family: var(--font-mono);
  color: var(--accent);
  font-size: clamp(1rem, 1.6vw, 1.2rem);
  margin-top: 16px;
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.hero-role .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
}

.hero-desc {
  margin-top: 24px;
  max-width: 46ch;
  color: var(--text-dim);
  font-size: 1.05rem;
}

.hero-actions {
  margin-top: 36px;
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 24px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 0.94rem;
  transition: transform 0.2s ease, background 0.2s ease, border-color 0.2s ease;
  border: 1px solid transparent;
}

.btn-primary {
  background: var(--accent);
  color: #16120a;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 28px rgba(255, 184, 51, 0.22);
}

.btn-ghost {
  border-color: var(--line-strong);
  color: var(--text);
}

.btn-ghost:hover {
  border-color: var(--accent-line);
  background: var(--accent-soft);
}

.hero-meta {
  margin-top: 44px;
  display: flex;
  gap: 32px;
  flex-wrap: wrap;
}

.hero-meta div {
  font-family: var(--font-mono);
}

.hero-meta .num {
  font-size: 1.4rem;
  color: var(--text);
  font-weight: 600;
}

.hero-meta .label {
  font-size: 0.78rem;
  color: var(--text-faint);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-top: 4px;
}

/* ---------------- About ---------------- */

.about .container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: start;
}

.about-body p {
  color: var(--text-dim);
  margin-bottom: 18px;
  font-size: 1.02rem;
}

.about-body p strong {
  color: var(--text);
  font-weight: 600;
}

.stat-row {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}

.stat {
  background: var(--surface);
  padding: 26px 22px;
}

.stat .num {
  font-family: var(--font-display);
  font-size: 1.7rem;
  font-weight: 700;
  color: var(--accent);
}

.stat .label {
  margin-top: 6px;
  font-size: 0.86rem;
  color: var(--text-dim);
}

/* ---------------- Skills ---------------- */

.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}

.skill-card {
  background: var(--surface);
  padding: 28px;
}

.skill-card h3 {
  font-size: 0.95rem;
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent);
  margin-bottom: 16px;
}

.tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag {
  font-size: 0.84rem;
  padding: 6px 12px;
  border-radius: 999px;
  border: 1px solid var(--line-strong);
  color: var(--text-dim);
}

/* ---------------- Projects hub ---------------- */

.projects-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}

.project-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px;
  display: flex;
  flex-direction: column;
  gap: 14px;
  transition: border-color 0.2s ease, transform 0.2s ease, background 0.2s ease;
  position: relative;
}

.project-card:hover {
  border-color: var(--accent-line);
  transform: translateY(-3px);
  background: var(--surface-2);
}

.project-card.current {
  border-color: var(--accent-line);
  background: linear-gradient(160deg, var(--accent-soft), var(--surface));
}

.card-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.card-num {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-faint);
}

.card-status {
  font-family: var(--font-mono);
  font-size: 0.66rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 3px 9px;
  border-radius: 999px;
  border: 1px solid var(--line-strong);
  color: var(--text-faint);
}

.card-status.live {
  color: #16120a;
  background: var(--accent);
  border-color: var(--accent);
}

.card-status.here {
  color: var(--accent);
  border-color: var(--accent-line);
}

.project-card h3 {
  font-size: 1.15rem;
  font-weight: 600;
}

.project-card p {
  color: var(--text-dim);
  font-size: 0.92rem;
  flex-grow: 1;
}

.card-links {
  display: flex;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 0.8rem;
}

.card-links a {
  color: var(--text-dim);
  display: inline-flex;
  align-items: center;
  gap: 5px;
  transition: color 0.2s ease;
}

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

.card-links span.sep {
  color: var(--text-faint);
}

.card-links a.link-pending {
  color: var(--text-faint);
  border-bottom: 1px dashed var(--text-faint);
  cursor: default;
}

.projects-note {
  margin-top: 28px;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--text-faint);
  border-left: 2px solid var(--accent-line);
  padding-left: 14px;
}

/* ---------------- Research / other builds ---------------- */

.research-list {
  display: flex;
  flex-direction: column;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}

.research-item {
  background: var(--surface);
  padding: 24px 28px;
  display: grid;
  grid-template-columns: 160px 1fr;
  gap: 24px;
}

.research-item .org {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-faint);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.research-item h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 6px;
}

.research-item p {
  color: var(--text-dim);
  font-size: 0.94rem;
}

/* ---------------- Contact ---------------- */

.contact .container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
}

.contact-lines {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.contact-line {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 18px 20px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 10px;
  transition: border-color 0.2s ease;
}

.contact-line:hover {
  border-color: var(--accent-line);
}

.contact-line .icon {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  background: var(--surface-2);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.contact-line .icon svg { width: 17px; height: 17px; }

.contact-line .label {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-faint);
  font-family: var(--font-mono);
}

.contact-line .value {
  margin-top: 2px;
  font-size: 0.98rem;
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.contact-form input,
.contact-form textarea {
  width: 100%;
  background: var(--surface);
  border: 1px solid var(--line-strong);
  border-radius: 10px;
  padding: 14px 16px;
  color: var(--text);
  font-family: var(--font-body);
  font-size: 0.96rem;
  resize: vertical;
}

.contact-form input:focus,
.contact-form textarea:focus {
  outline: none;
  border-color: var(--accent);
}

.contact-form textarea {
  min-height: 130px;
}

.form-status {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--accent);
  min-height: 1.2em;
}

/* ---------------- Footer ---------------- */

footer {
  padding: 40px 0;
}

footer .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 0.86rem;
  color: var(--text-faint);
}

.footer-socials {
  display: flex;
  gap: 18px;
}

.footer-socials a {
  color: var(--text-dim);
  transition: color 0.2s ease;
}

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

/* ---------------- Reveal on scroll ---------------- */

.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.in-view {
  opacity: 1;
  transform: translateY(0);
}

/* ---------------- Responsive ---------------- */

@media (max-width: 960px) {
  .about .container,
  .contact .container {
    grid-template-columns: 1fr;
  }
  .projects-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .research-item {
    grid-template-columns: 1fr;
    gap: 8px;
  }
}

@media (max-width: 720px) {
  section {
    padding: 64px 0;
  }
  .nav-links {
    position: fixed;
    top: 0;
    right: 0;
    height: 100vh;
    width: min(78vw, 320px);
    background: var(--surface);
    border-left: 1px solid var(--line);
    flex-direction: column;
    align-items: flex-start;
    padding: 100px 32px 32px;
    gap: 28px;
    transform: translateX(100%);
    transition: transform 0.3s ease;
  }
  .nav-links.open {
    transform: translateX(0);
  }
  .nav-toggle {
    display: flex;
  }
  .hero {
    padding-top: 140px;
  }
  .projects-grid {
    grid-template-columns: 1fr;
  }
  .hero-meta {
    gap: 24px;
  }
}

@media (max-width: 420px) {
  .container {
    padding-inline: 18px;
  }
}