/* ============================================================
   Space-themed landing page for kalkan.github.io
   ============================================================ */

:root {
  --bg-deep: #03051a;
  --bg-mid: #0a0f2e;
  --bg-nebula-a: rgba(99, 72, 198, 0.25);
  --bg-nebula-b: rgba(46, 196, 182, 0.18);
  --bg-nebula-c: rgba(255, 88, 152, 0.12);
  --text: #e6ecff;
  --text-soft: #aab3d5;
  --text-dim: #7a86b6;
  --accent: #6ee7ff;
  --accent-2: #b28cff;
  --accent-3: #ffd166;
  --card-bg: rgba(14, 22, 55, 0.55);
  --card-border: rgba(120, 150, 255, 0.18);
  --card-glow: rgba(110, 231, 255, 0.15);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: radial-gradient(ellipse at top, #0b1140 0%, #03051a 55%, #02030f 100%);
  color: var(--text);
  font-family: 'Inter', system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
  overflow-x: hidden;
  scroll-behavior: smooth;
  line-height: 1.6;
}

body { min-height: 100vh; position: relative; }

a { color: var(--accent); text-decoration: none; transition: color 0.2s ease; }
a:hover { color: var(--accent-2); }

/* --------------------------- Starfield --------------------------- */
.stars {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-repeat: repeat;
}
.stars-1 {
  background-image:
    radial-gradient(1px 1px at 20px 30px, #fff, transparent),
    radial-gradient(1px 1px at 80px 120px, #fff, transparent),
    radial-gradient(1.5px 1.5px at 160px 60px, #cfe6ff, transparent),
    radial-gradient(1px 1px at 240px 200px, #fff, transparent),
    radial-gradient(1px 1px at 300px 50px, #fff, transparent);
  background-size: 350px 350px;
  animation: drift 120s linear infinite;
  opacity: 0.9;
}
.stars-2 {
  background-image:
    radial-gradient(1.5px 1.5px at 40px 100px, #fff, transparent),
    radial-gradient(1px 1px at 180px 40px, #ffe0a8, transparent),
    radial-gradient(2px 2px at 260px 180px, #fff, transparent),
    radial-gradient(1px 1px at 340px 260px, #cfe6ff, transparent);
  background-size: 500px 500px;
  animation: drift 200s linear infinite reverse;
  opacity: 0.7;
}
.stars-3 {
  background-image:
    radial-gradient(1px 1px at 60px 80px, #fff, transparent),
    radial-gradient(2.5px 2.5px at 220px 220px, #ffd6e0, transparent),
    radial-gradient(1.5px 1.5px at 380px 120px, #fff, transparent);
  background-size: 700px 700px;
  animation: drift 320s linear infinite, twinkle 5s ease-in-out infinite;
  opacity: 0.5;
}

@keyframes drift {
  from { background-position: 0 0; }
  to   { background-position: 1000px 1000px; }
}
@keyframes twinkle {
  0%, 100% { opacity: 0.5; }
  50%      { opacity: 0.85; }
}

.nebula {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background:
    radial-gradient(circle at 20% 20%, var(--bg-nebula-a), transparent 45%),
    radial-gradient(circle at 80% 10%, var(--bg-nebula-b), transparent 40%),
    radial-gradient(circle at 60% 80%, var(--bg-nebula-c), transparent 50%);
  filter: blur(20px);
  animation: nebulaShift 30s ease-in-out infinite alternate;
}
@keyframes nebulaShift {
  from { transform: translate3d(0,0,0) scale(1); }
  to   { transform: translate3d(-30px,20px,0) scale(1.1); }
}

/* --------------------------- Navigation --------------------------- */
.space-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 36px;
  background: rgba(3, 5, 26, 0.55);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(120, 150, 255, 0.08);
}
.space-nav .brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  font-family: 'Orbitron', sans-serif;
  font-weight: 700;
  letter-spacing: 1px;
  font-size: 15px;
}
.brand-dot {
  width: 10px; height: 10px;
  border-radius: 50%;
  background: radial-gradient(circle, #6ee7ff 0%, #1f3bff 80%);
  box-shadow: 0 0 10px #6ee7ff, 0 0 20px #1f3bff;
  animation: pulse 2.4s ease-in-out infinite;
}
@keyframes pulse {
  0%,100% { transform: scale(1); opacity: 1; }
  50%     { transform: scale(1.25); opacity: 0.8; }
}
.space-nav ul {
  display: flex;
  gap: 28px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.space-nav ul a {
  color: var(--text-soft);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.4px;
  padding: 6px 2px;
  border-bottom: 1px solid transparent;
  transition: color 0.2s, border-color 0.2s;
}
.space-nav ul a:hover {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

/* --------------------------- Main / Hero --------------------------- */
.space-main {
  position: relative;
  z-index: 1;
  padding-top: 78px;
}

.hero {
  position: relative;
  min-height: 92vh;
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 40px;
  align-items: center;
  max-width: 1200px;
  margin: 0 auto;
  padding: 40px 36px;
}
.hero-text h1 {
  font-family: 'Orbitron', sans-serif;
  font-size: clamp(2.2rem, 5vw, 3.6rem);
  font-weight: 900;
  margin: 0 0 10px;
  background: linear-gradient(120deg, #ffffff 0%, #6ee7ff 45%, #b28cff 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  line-height: 1.1;
}
.hero-text .tagline {
  font-size: clamp(1rem, 1.6vw, 1.25rem);
  color: var(--accent);
  letter-spacing: 2px;
  text-transform: uppercase;
  font-family: 'Orbitron', sans-serif;
  margin: 0 0 24px;
}
.hero-text p.lead {
  font-size: 1.05rem;
  color: var(--text-soft);
  max-width: 560px;
  margin: 0 0 28px;
}
.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 22px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.5px;
  transition: transform 0.2s, box-shadow 0.2s, background 0.2s;
  border: 1px solid var(--card-border);
}
.btn-primary {
  background: linear-gradient(135deg, #6ee7ff 0%, #b28cff 100%);
  color: #0a0f2e;
  border-color: transparent;
  box-shadow: 0 8px 32px rgba(110, 231, 255, 0.25);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 40px rgba(110, 231, 255, 0.4);
  color: #0a0f2e;
}
.btn-ghost {
  background: rgba(255, 255, 255, 0.04);
  color: var(--text);
}
.btn-ghost:hover {
  background: rgba(110, 231, 255, 0.12);
  color: var(--accent);
  transform: translateY(-2px);
}

/* --------------------------- Orbit System --------------------------- */
.orbit-system {
  position: relative;
  width: 100%;
  aspect-ratio: 1 / 1;
  max-width: 480px;
  margin: 0 auto;
}
.orbit {
  position: absolute;
  inset: 0;
  border: 1px dashed rgba(120, 150, 255, 0.2);
  border-radius: 50%;
  animation: spin 40s linear infinite;
}
.orbit-2 { inset: 12%; border-color: rgba(178, 140, 255, 0.25); animation-duration: 25s; animation-direction: reverse; }
.orbit-3 { inset: 26%; border-color: rgba(110, 231, 255, 0.3);  animation-duration: 15s; }
@keyframes spin {
  to { transform: rotate(360deg); }
}

.planet {
  position: absolute;
  inset: 36%;
  border-radius: 50%;
  background:
    radial-gradient(circle at 30% 30%, #4da6ff 0%, #1f4fb5 45%, #0a1e5c 100%);
  box-shadow:
    inset -20px -30px 60px rgba(0,0,0,0.55),
    inset 20px 10px 40px rgba(110, 231, 255, 0.2),
    0 0 60px rgba(110, 231, 255, 0.35),
    0 0 120px rgba(31, 79, 181, 0.4);
  animation: spin 80s linear infinite;
}
.planet::before {
  content: "";
  position: absolute;
  inset: 15% 10% 55% 20%;
  background: radial-gradient(ellipse, rgba(140, 220, 160, 0.55), transparent 70%);
  filter: blur(4px);
  border-radius: 50%;
}
.planet::after {
  content: "";
  position: absolute;
  inset: 55% 25% 15% 15%;
  background: radial-gradient(ellipse, rgba(200, 170, 120, 0.45), transparent 70%);
  filter: blur(6px);
  border-radius: 50%;
}

.satellite {
  position: absolute;
  width: 22px;
  height: 22px;
  border-radius: 4px;
  background: linear-gradient(135deg, #e0e9ff, #8aa0d5);
  box-shadow: 0 0 16px rgba(110, 231, 255, 0.8), 0 0 32px rgba(110, 231, 255, 0.35);
}
.satellite::before,
.satellite::after {
  content: "";
  position: absolute;
  top: 50%;
  width: 18px;
  height: 8px;
  transform: translateY(-50%);
  background: repeating-linear-gradient(90deg, #2a4a8a 0 3px, #1a2a5a 3px 6px);
  border: 1px solid #4a6aaa;
}
.satellite::before { left: -20px; }
.satellite::after  { right: -20px; }

.sat-1 { top: -11px; left: calc(50% - 11px); }
.sat-2 { bottom: -11px; left: calc(50% - 11px); }

/* badge label */
.orbit-badge {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-family: 'Orbitron', sans-serif;
  font-size: 11px;
  letter-spacing: 3px;
  color: var(--accent);
  text-shadow: 0 0 12px rgba(110, 231, 255, 0.8);
  pointer-events: none;
}

/* --------------------------- Sections --------------------------- */
.section {
  max-width: 1100px;
  margin: 0 auto;
  padding: 80px 36px 40px;
  position: relative;
}
.section h2 {
  font-family: 'Orbitron', sans-serif;
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  font-weight: 700;
  margin: 0 0 8px;
  background: linear-gradient(120deg, #fff, #6ee7ff);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.section .section-sub {
  color: var(--text-dim);
  font-size: 14px;
  letter-spacing: 2px;
  text-transform: uppercase;
  margin-bottom: 32px;
  font-family: 'Orbitron', sans-serif;
}

/* About */
.about-grid {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 40px;
  align-items: start;
}
.about-photo {
  width: 220px;
  height: 220px;
  border-radius: 50%;
  object-fit: cover;
  border: 2px solid rgba(110, 231, 255, 0.35);
  box-shadow:
    0 0 0 6px rgba(3, 5, 26, 0.6),
    0 0 40px rgba(110, 231, 255, 0.3),
    0 0 80px rgba(178, 140, 255, 0.2);
}
.about-body p {
  color: var(--text-soft);
  margin: 0 0 16px;
}
.about-body p a { color: var(--accent); }
.about-body p a:hover { color: var(--accent-2); }

/* Research cards */
.research-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
}
.card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-radius: 18px;
  padding: 24px;
  position: relative;
  overflow: hidden;
  transition: transform 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
}
.card::before {
  content: "";
  position: absolute;
  inset: -1px;
  border-radius: 18px;
  padding: 1px;
  background: linear-gradient(135deg, rgba(110,231,255,0.4), transparent 60%);
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
          mask-composite: exclude;
  opacity: 0;
  transition: opacity 0.3s;
  pointer-events: none;
}
.card:hover {
  transform: translateY(-4px);
  border-color: rgba(110, 231, 255, 0.4);
  box-shadow: 0 20px 50px rgba(3, 5, 26, 0.6), 0 0 40px var(--card-glow);
}
.card:hover::before { opacity: 1; }

.card .icon {
  width: 44px; height: 44px;
  border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  font-size: 22px;
  background: linear-gradient(135deg, rgba(110,231,255,0.2), rgba(178,140,255,0.2));
  border: 1px solid rgba(110, 231, 255, 0.3);
  margin-bottom: 14px;
}
.card h3 {
  font-family: 'Orbitron', sans-serif;
  font-size: 1.05rem;
  margin: 0 0 8px;
  color: var(--text);
}
.card p {
  font-size: 0.92rem;
  color: var(--text-soft);
  margin: 0;
}

/* Explore (link cards) */
.explore-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 18px;
}
.explore-card {
  display: block;
  padding: 22px;
  border-radius: 16px;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  color: var(--text);
  transition: transform 0.25s, border-color 0.25s, box-shadow 0.25s;
  position: relative;
  overflow: hidden;
}
.explore-card::after {
  content: "→";
  position: absolute;
  top: 18px; right: 20px;
  font-size: 18px;
  color: var(--accent);
  transition: transform 0.25s;
}
.explore-card:hover {
  transform: translateY(-3px);
  border-color: rgba(110, 231, 255, 0.45);
  box-shadow: 0 16px 44px rgba(3, 5, 26, 0.6);
  color: var(--text);
}
.explore-card:hover::after { transform: translateX(4px); }
.explore-card .label {
  font-size: 11px;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--accent);
  font-family: 'Orbitron', sans-serif;
}
.explore-card h3 {
  font-family: 'Orbitron', sans-serif;
  font-size: 1.1rem;
  margin: 8px 0 6px;
}
.explore-card p {
  font-size: 0.9rem;
  color: var(--text-soft);
  margin: 0;
}

/* Timeline (career) */
.timeline {
  position: relative;
  margin: 20px 0 0;
  padding-left: 28px;
  border-left: 1px dashed rgba(110, 231, 255, 0.25);
}
.timeline li {
  list-style: none;
  position: relative;
  padding: 0 0 22px 10px;
}
.timeline li::before {
  content: "";
  position: absolute;
  left: -35px;
  top: 6px;
  width: 12px; height: 12px;
  border-radius: 50%;
  background: radial-gradient(circle, #6ee7ff 0%, #1f3bff 85%);
  box-shadow: 0 0 10px rgba(110, 231, 255, 0.9);
}
.timeline .when {
  font-family: 'Orbitron', sans-serif;
  font-size: 12px;
  letter-spacing: 2px;
  color: var(--accent);
  text-transform: uppercase;
}
.timeline .what {
  color: var(--text);
  font-weight: 600;
  margin: 2px 0 4px;
}
.timeline .where {
  color: var(--text-dim);
  font-size: 14px;
}

/* Contact */
.contact-wrap {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 32px;
  align-items: center;
}
.contact-wrap .card {
  padding: 30px;
}
.contact-list {
  list-style: none;
  padding: 0;
  margin: 0;
}
.contact-list li {
  padding: 10px 0;
  color: var(--text-soft);
  display: flex;
  align-items: center;
  gap: 10px;
  border-bottom: 1px dashed rgba(120, 150, 255, 0.12);
}
.contact-list li:last-child { border-bottom: none; }
.contact-list .k {
  font-family: 'Orbitron', sans-serif;
  font-size: 11px;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--accent);
  min-width: 90px;
}

/* Footer */
.space-footer {
  position: relative;
  z-index: 1;
  padding: 40px 24px 60px;
  text-align: center;
  color: var(--text-dim);
  font-size: 13px;
  border-top: 1px solid rgba(120, 150, 255, 0.08);
  margin-top: 60px;
}
.orbit-footer a { color: var(--text-soft); }
.orbit-footer a:hover { color: var(--accent); }
.orbit-footer .sep { margin: 0 10px; opacity: 0.5; }

/* Responsive */
@media (max-width: 820px) {
  .space-nav { padding: 14px 18px; }
  .space-nav ul { display: none; }
  .hero {
    grid-template-columns: 1fr;
    padding: 80px 22px 40px;
    min-height: auto;
    gap: 20px;
  }
  .orbit-system { max-width: 340px; }
  .about-grid { grid-template-columns: 1fr; gap: 22px; }
  .about-photo { width: 160px; height: 160px; margin: 0 auto; display: block; }
  .contact-wrap { grid-template-columns: 1fr; }
  .section { padding: 60px 22px 20px; }
}

/* shooting star */
.shooting-star {
  position: fixed;
  top: 20%; left: -10%;
  width: 2px; height: 2px;
  background: #fff;
  box-shadow: 0 0 8px 2px #fff;
  border-radius: 50%;
  z-index: 0;
  animation: shoot 9s ease-in infinite;
}
.shooting-star::before {
  content: "";
  position: absolute;
  top: 0; left: 0;
  width: 140px; height: 1px;
  background: linear-gradient(90deg, rgba(255,255,255,0.9), transparent);
  transform-origin: left;
  transform: rotate(-14deg);
}
@keyframes shoot {
  0%   { transform: translate(0, 0); opacity: 0; }
  5%   { opacity: 1; }
  40%  { transform: translate(120vw, 30vh); opacity: 0; }
  100% { transform: translate(120vw, 30vh); opacity: 0; }
}