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

html, body {min-height: 100%; }

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: radial-gradient(circle at top, #020617 0%, #020617 40%, #000 100%);
  color: #e5e7eb;
  overflow-x: hidden;
  overflow-y: auto;
}

.starfield {
  position: fixed;
  inset: 0;
  overflow: visible;
  pointer-events: none;
  z-index: 0;
  background: radial-gradient(circle at center, #020617 0%, #020617 35%, #000 100%);
  display: flex;
  align-items: center;
  justify-content: center;
}

.starfield-inner {
  position: relative;
  width: 160vmin;
  height: 160vmin;
  animation: starfield-spin 120s linear infinite;
}

.star {
  position: absolute;
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: white;
  box-shadow: 0 0 6px rgba(255, 255, 255, 0.8);
  opacity: 0.3;
}

@keyframes star-twinkle {
  0%, 100% {
    opacity: 0.15;
    transform: scale(0.7);
  }
  50% {
    opacity: 0.9;
    transform: scale(1.6);
  }
}

@keyframes starfield-spin {
  0% {
    transform: rotate(0deg) scale(1);
  }
  50% {
    transform: rotate(180deg) scale(1.05);
  }
  100% {
    transform: rotate(360deg) scale(1);
  }
}

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 10;
  padding: 1.2rem 5vw;
  display: flex;
  justify-content: space-between;
  align-items: center;
  backdrop-filter: blur(12px);
  background: linear-gradient(
    to bottom,
    rgba(15, 23, 42, 0.9),
    rgba(15, 23, 42, 0.3),
    transparent
  );
  border-bottom: 1px solid rgba(148, 163, 184, 0.2);
}

.logo {
  font-weight: 700;
  letter-spacing: 0.2em;
  font-size: 1rem;
  text-transform: uppercase;
  color: #e5e7eb;
}

.nav {
  display: flex;
  gap: 1.2rem;
}

.nav-link {
  font-size: 0.95rem;
  color: #9ca3af;
  text-decoration: none;
  position: relative;
  padding-bottom: 0.2rem;
}

.nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0%;
  height: 2px;
  background: linear-gradient(90deg, #38bdf8, #a855f7);
  transition: width 0.3s ease-out;
}

.nav-link:hover {
  color: #e5e7eb;
}

.nav-link:hover::after,
.nav-link.active::after {
  width: 100%;
}

.nav-link.active {
  color: #f9fafb;
}

.hero {
  position: relative;
  z-index: 1;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 6rem 5vw 3rem;
  text-align: center;
}

.hero-content {
  max-width: 640px;
}

.hero-kicker {
  text-transform: uppercase;
  letter-spacing: 0.25em;
  color: #9ca3af;
  font-size: 0.75rem;
  margin-bottom: 0.75rem;
}

.hero-title {
  font-size: clamp(2.7rem, 5vw, 3.8rem);
  font-weight: 700;
  letter-spacing: 0.03em;
  background: linear-gradient(135deg, #e5e7eb, #a5b4fc, #38bdf8, #a855f7);
  background-clip: text;
  -webkit-background-clip: text;
  color: transparent;
  margin-bottom: 0.6rem;
}

.hero-subtitle {
  font-size: 1rem;
  line-height: 1.7;
  color: #9ca3af;
  margin-bottom: 1.5rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
  align-items: center;
  justify-content: center;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  padding: 0.75rem 1.4rem;
  font-size: 0.9rem;
  border: 1px solid transparent;
  cursor: pointer;
  text-decoration: none;
  transition:
    background 0.2s ease-out,
    border-color 0.2s ease-out,
    color 0.2s ease-out,
    transform 0.15s ease-out;
}

.btn-primary {
  background: radial-gradient(circle at top left, #38bdf8, #a855f7);
  color: #0b1120;
  font-weight: 600;
}

.btn-primary:hover {
  transform: translateY(-1px) scale(1.02);
  box-shadow: 0 0 30px rgba(56, 189, 248, 0.5);
}

.btn-ghost {
  background: transparent;
  border-color: rgba(148, 163, 184, 0.6);
  color: #e5e7eb;
}

.btn-ghost:hover {
  border-color: #a855f7;
  color: #f9fafb;
  transform: translateY(-1px);
}

.hero-note {
  font-size: 0.8rem;
  color: #6b7280;
}

.tag {
  font-size: 0.8rem;
  color: #e5e7eb;
  border: 1px solid rgba(148, 163, 184, 0.25);
  background: rgba(2, 6, 23, 0.35);
  padding: 0.35rem 0.7rem;
  border-radius: 999px;
}

/* =========================
   About page
   ========================= */
.about {
  position: relative;
  z-index: 1;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 7rem 5vw 3rem;
}

.about-card {
  width: min(980px, 100%);
  border: 1px solid rgba(148, 163, 184, 0.18);
  background: rgba(2, 6, 23, 0.55);
  backdrop-filter: blur(14px);
  border-radius: 24px;
  padding: clamp(1.25rem, 3.2vw, 2rem);
  box-shadow: 0 0 60px rgba(0, 0, 0, 0.35);
}

.about-kicker {
  text-transform: uppercase;
  letter-spacing: 0.25em;
  color: #9ca3af;
  font-size: 0.75rem;
  margin-bottom: 0.75rem;
}

.about-title {
  font-size: clamp(2.0rem, 4vw, 3.0rem);
  font-weight: 750;
  letter-spacing: 0.02em;
  background: linear-gradient(135deg, #e5e7eb, #93c5fd, #60a5fa, #3b82f6);
  background-clip: text;
  -webkit-background-clip: text;
  color: transparent;
  margin-bottom: 1.25rem;
}

.about-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 1rem;
  margin-bottom: 1.1rem;
}

.about-panel {
  border: 1px solid rgba(148, 163, 184, 0.14);
  background: rgba(15, 23, 42, 0.35);
  border-radius: 18px;
  padding: 1.1rem;
}

.about-panel h2 {
  font-size: 1rem;
  margin-bottom: 0.5rem;
  color: #f9fafb;
  letter-spacing: 0.02em;
}

.about-panel p {
  color: #cbd5e1;
  line-height: 1.7;
  margin-bottom: 0.75rem;
}

/* =========================
   Education page
   ========================= */
body.page-education {
  background: radial-gradient(circle at 20% 10%, #062a33 0%, #071a2a 45%, #000 100%);
  overflow-x: hidden;
  overflow-y: auto;
}

.bg-pattern {
  position: fixed;
  inset: 0;
  z-index: 1;
  pointer-events: none;

  background:
    radial-gradient(circle at 25% 20%, rgba(56, 189, 248, 0.14), transparent 55%),
    radial-gradient(circle at 70% 65%, rgba(34, 211, 238, 0.10), transparent 55%),
    repeating-linear-gradient(
      0deg,
      rgba(148, 163, 184, 0.08) 0px,
      rgba(148, 163, 184, 0.08) 1px,
      transparent 1px,
      transparent 34px
    ),
    repeating-linear-gradient(
      90deg,
      rgba(148, 163, 184, 0.06) 0px,
      rgba(148, 163, 184, 0.06) 1px,
      transparent 1px,
      transparent 34px
    );

  opacity: 0.98;
  animation: edu-grid-drift 32s ease-in-out infinite alternate;
}

@keyframes edu-grid-drift {
  0%   { transform: translate3d(-1.5%, -1%, 0) scale(1); }
  100% { transform: translate3d(1.5%, 1%, 0) scale(1.02); }
}

.edu {
  position: relative;
  z-index: 2;
  min-height: 100vh;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 7rem 5vw 3rem;
}

.edu-card {
  width: min(1100px, 100%);
  border: 1px solid rgba(148, 163, 184, 0.18);
  background: rgba(2, 6, 23, 0.55);
  backdrop-filter: blur(14px);
  border-radius: 24px;
  padding: clamp(1.25rem, 3.2vw, 2rem);
  box-shadow: 0 0 60px rgba(0, 0, 0, 0.35);
}

.edu-kicker {
  text-transform: uppercase;
  letter-spacing: 0.25em;
  color: #9ca3af;
  font-size: 0.75rem;
  margin-bottom: 0.75rem;
}

.edu-title {
  font-size: clamp(2.1rem, 4vw, 3.1rem);
  font-weight: 750;
  letter-spacing: 0.02em;
  background: linear-gradient(135deg, #e5e7eb, #7dd3fc, #38bdf8, #60a5fa);
  background-clip: text;
  -webkit-background-clip: text;
  color: transparent;
  margin-bottom: 1rem;
}

.edu-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.2rem;
}

.edu-pill {
  font-size: 0.85rem;
  color: #e5e7eb;
  border: 1px solid rgba(148, 163, 184, 0.22);
  background: rgba(2, 6, 23, 0.35);
  padding: 0.4rem 0.75rem;
  border-radius: 999px;
}

.edu-grid {
  display: grid;
  grid-template-columns: 1.25fr 0.75fr;
  gap: 1rem;
}

.edu-panel {
  border: 1px solid rgba(148, 163, 184, 0.14);
  background: rgba(15, 23, 42, 0.35);
  border-radius: 18px;
  padding: 1.1rem;
}

.edu-panel h2 {
  font-size: 1rem;
  margin-bottom: 0.75rem;
  color: #f9fafb;
  letter-spacing: 0.02em;
}

.edu-text {
  color: #cbd5e1;
  line-height: 1.7;
  margin-bottom: 0.75rem;
}

.edu-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 0.5rem 0 1rem;
}

.edu-actions {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin-bottom: 0.75rem;
}

.edu-note {
  color: #94a3b8;
  font-size: 0.85rem;
}

.course-groups {
  display: grid;
  gap: 1.25rem;
}

.course-group-header h3 {
  font-size: 1rem;
  color: #f9fafb;
  margin-bottom: 0.25rem;
  letter-spacing: 0.02em;
}

.course-group-header p {
  color: #9ca3af;
  font-size: 0.9rem;
  line-height: 1.5;
  margin-bottom: 0.75rem;
}

.course-list {
  display: grid;
  gap: 0.65rem;
}

.course {
  border: 1px solid rgba(148, 163, 184, 0.12);
  background: rgba(2, 6, 23, 0.25);
  border-radius: 14px;
  padding: 0.75rem 0.85rem;
}

.course h4 {
  font-size: 0.95rem;
  color: #f9fafb;
  margin: 0;
  line-height: 1.35;
}

@media (max-width: 900px) {
  body { overflow: auto; }
  .edu-grid {
    grid-template-columns: 1fr;
  }
  .about-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .site-header {
    padding-inline: 1.25rem;
  }

  .nav {
    gap: 0.9rem;
  }

  .hero {
    padding-inline: 1.25rem;
    text-align: left;
  }

  .hero-actions {
    justify-content: flex-start;
  }
}

.course-toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.6rem;
  margin: 0.75rem 0 1.25rem;
  position: relative;
  z-index: 2;
}

.filter-btn {
  border-radius: 999px;
  padding: 0.45rem 0.85rem;
  border: 1px solid rgba(148, 163, 184, 0.28);
  background: rgba(2, 6, 23, 0.35);
  color: #e5e7eb;
  font-size: 0.85rem;
  cursor: pointer;
  transition: transform 0.15s ease-out, border-color 0.2s ease-out;
}

.filter-btn:hover {
  transform: translateY(-1px);
  border-color: rgba(56, 189, 248, 0.7);
}

.filter-btn.active {
  border-color: rgba(56, 189, 248, 0.95);
  box-shadow: 0 0 24px rgba(56, 189, 248, 0.18);
}

.course-count {
  margin-left: auto;
  color: #9ca3af;
  font-size: 0.85rem;
}

/* =========================
   Experience page
   ========================= */

body.page-experience {
  background: radial-gradient(circle at 15% 10%, #1b1438 0%, #071226 45%, #000 100%);
}

body.page-experience .starfield {
  opacity: 0.22;
  filter: blur(0.6px);
}

.exp-pattern {
  position: fixed;
  inset: 0;
  z-index: 1;
  pointer-events: none;

  background:
    radial-gradient(circle at 20% 25%, rgba(168, 85, 247, 0.14), transparent 55%),
    radial-gradient(circle at 75% 60%, rgba(59, 130, 246, 0.10), transparent 60%),
    radial-gradient(circle at 55% 15%, rgba(34, 211, 238, 0.06), transparent 55%),

    radial-gradient(rgba(148, 163, 184, 0.08) 1px, transparent 1px);

  background-size:
    auto,
    auto,
    auto,
    22px 22px;

  opacity: 0.55;
  filter: blur(0.25px);
  animation: exp-aurora-drift 22s ease-in-out infinite alternate;
}

@keyframes exp-aurora-drift {
  0%   { transform: translate3d(-1.2%, -0.8%, 0) scale(1); }
  100% { transform: translate3d(1.2%, 1%, 0) scale(1.03); }
}

.exp {
  position: relative;
  z-index: 2;
  display: flex;
  justify-content: center;
  padding: 7rem 5vw 3rem;
}

.exp-card {
  width: min(1100px, 100%);
  border: 1px solid rgba(148, 163, 184, 0.18);
  background: rgba(2, 6, 23, 0.55);
  backdrop-filter: blur(14px);
  border-radius: 24px;
  padding: clamp(1.25rem, 3.2vw, 2rem);
  box-shadow: 0 0 60px rgba(0, 0, 0, 0.35);
}

.exp-kicker {
  text-transform: uppercase;
  letter-spacing: 0.25em;
  color: #9ca3af;
  font-size: 0.75rem;
  margin-bottom: 0.75rem;
}

.exp-title {
  font-size: clamp(2.1rem, 4vw, 3.1rem);
  font-weight: 750;
  letter-spacing: 0.02em;
  background: linear-gradient(135deg, #e5e7eb, #c4b5fd, #60a5fa, #22d3ee);
  background-clip: text;
  -webkit-background-clip: text;
  color: transparent;
  margin-bottom: 0.6rem;
}

.exp-subtitle {
  color: #9ca3af;
  line-height: 1.7;
  margin-bottom: 1.1rem;
}

.exp-toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.6rem;
  margin: 0.75rem 0 1.25rem;
}

.exp-filter-btn {
  border-radius: 999px;
  padding: 0.45rem 0.85rem;
  border: 1px solid rgba(148, 163, 184, 0.28);
  background: rgba(2, 6, 23, 0.35);
  color: #e5e7eb;
  font-size: 0.85rem;
  cursor: pointer;
  transition: transform 0.15s ease-out, border-color 0.2s ease-out;
}

.exp-filter-btn:hover {
  transform: translateY(-1px);
  border-color: rgba(196, 181, 253, 0.8);
}

.exp-filter-btn.active {
  border-color: rgba(34, 211, 238, 0.9);
  box-shadow: 0 0 24px rgba(34, 211, 238, 0.18);
}

.exp-count {
  margin-left: auto;
  color: #9ca3af;
  font-size: 0.85rem;
}

.exp-layout {
  display: grid;
  grid-template-columns: 1.35fr 0.65fr;
  gap: 1rem;
}

.exp-timeline {
  position: relative;
  padding-left: 1.15rem;
}

.exp-timeline::before {
  content: "";
  position: absolute;
  left: 0.35rem;
  top: 0.2rem;
  bottom: 0.2rem;
  width: 2px;
  background: linear-gradient(
    to bottom,
    rgba(34, 211, 238, 0.0),
    rgba(34, 211, 238, 0.35),
    rgba(168, 85, 247, 0.35),
    rgba(34, 211, 238, 0.0)
  );
}

.exp-section-title {
  font-size: 1rem;
  margin-bottom: 0.75rem;
  color: #f9fafb;
  letter-spacing: 0.02em;
}

.exp-section-title-small {
  margin-top: 1rem;
  margin-bottom: 0.75rem;
  opacity: 0.95;
}

.exp-divider {
  height: 1px;
  background: rgba(148, 163, 184, 0.18);
  margin: 1.25rem 0 0.75rem;
}

.exp-item {
  position: relative;
  margin-bottom: 1rem;
}

.exp-dot {
  position: absolute;
  left: -0.2rem;
  top: 1rem;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: rgba(34, 211, 238, 0.9);
  box-shadow: 0 0 18px rgba(34, 211, 238, 0.35);
}

.exp-dot-project {
  background: rgba(196, 181, 253, 0.95);
  box-shadow: 0 0 18px rgba(196, 181, 253, 0.35);
}

.exp-item-card {
  border: 1px solid rgba(148, 163, 184, 0.12);
  background: rgba(2, 6, 23, 0.25);
  border-radius: 18px;
  padding: 1rem;
}

.exp-item-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 0.75rem;
  margin-bottom: 0.6rem;
}

.exp-role {
  font-size: 1rem;
  color: #f9fafb;
  margin-bottom: 0.2rem;
}

.exp-meta {
  font-size: 0.85rem;
  color: #9ca3af;
}

.exp-badge {
  font-size: 0.75rem;
  padding: 0.25rem 0.6rem;
  border-radius: 999px;
  border: 1px solid rgba(148, 163, 184, 0.25);
  color: #e5e7eb;
  background: rgba(2, 6, 23, 0.35);
  white-space: nowrap;
}

.exp-badge-project {
  border-color: rgba(196, 181, 253, 0.55);
}

.exp-bullets {
  margin-left: 1.1rem;
  margin-bottom: 0.75rem;
  color: #cbd5e1;
}

.exp-bullets li {
  margin-bottom: 0.4rem;
  line-height: 1.6;
}

.exp-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.exp-details summary {
  cursor: pointer;
  color: #93c5fd;
  font-size: 0.9rem;
  margin: 0.2rem 0 0.6rem;
}

.exp-details p {
  color: #cbd5e1;
  line-height: 1.7;
  margin: 0 0 0.75rem;
}

.exp-skillcard {
  border: 1px solid rgba(148, 163, 184, 0.12);
  background: rgba(2, 6, 23, 0.25);
  border-radius: 18px;
  padding: 1rem;
  margin-top: 1rem;
}

.exp-skilltext {
  color: #cbd5e1;
  line-height: 1.7;
  margin-bottom: 0.75rem;
}

.exp-side {
  display: grid;
  gap: 1rem;
  align-content: start;
}

.exp-side-card {
  border: 1px solid rgba(148, 163, 184, 0.14);
  background: rgba(15, 23, 42, 0.35);
  border-radius: 18px;
  padding: 1.1rem;
}

.exp-side-card h2 {
  font-size: 1rem;
  margin-bottom: 0.75rem;
  color: #f9fafb;
  letter-spacing: 0.02em;
}

.exp-side-card p {
  color: #cbd5e1;
  line-height: 1.7;
  margin-bottom: 0.75rem;
}

.exp-side-note {
  color: #94a3b8;
  font-size: 0.85rem;
  margin-top: 0.75rem;
}

.exp-side-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

@media (max-width: 900px) {
  .exp-layout {
    grid-template-columns: 1fr;
  }
  .exp-timeline {
    padding-left: 1.0rem;
  }
}