/* =============================================
   CSS Variables
   ============================================= */
:root {
  --color-primary:     #2563eb;
  --color-primary-dark:#1d4ed8;
  --color-accent:      #6366f1;
  --color-text:        #0f172a;
  --color-text-muted:  #64748b;
  --color-bg:          #ffffff;
  --color-bg-2:        #f8fafc;
  --color-border:      rgba(0, 0, 0, 0.08);

  --font:              'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

  --radius-sm:  0.375rem;
  --radius-md:  0.625rem;
  --radius-lg:  1rem;
  --radius-xl:  1.5rem;
  --radius-full:9999px;

  --shadow-sm:  0 1px 3px rgba(0,0,0,.06), 0 1px 2px rgba(0,0,0,.04);
  --shadow-md:  0 4px 16px rgba(0,0,0,.08);
  --shadow-lg:  0 12px 40px rgba(0,0,0,.12);

  --transition: 0.25s ease;
  --header-h:   64px;
}

[data-theme="dark"] {
  --color-primary:     #3b82f6;
  --color-primary-dark:#2563eb;
  --color-accent:      #818cf8;
  --color-text:        #f1f5f9;
  --color-text-muted:  #94a3b8;
  --color-bg:          #0a0f1e;
  --color-bg-2:        #111827;
  --color-border:      rgba(255,255,255,.08);

  --shadow-sm: 0 1px 3px rgba(0,0,0,.4);
  --shadow-md: 0 4px 16px rgba(0,0,0,.4);
  --shadow-lg: 0 12px 40px rgba(0,0,0,.5);
}

/* =============================================
   Reset & Base
   ============================================= */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; font-size: 16px; }

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

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

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

button { font-family: inherit; }

.container {
  max-width: 1160px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* =============================================
   Buttons
   ============================================= */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.6rem 1.35rem;
  border-radius: var(--radius-md);
  font-size: 0.9375rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: transform var(--transition), box-shadow var(--transition), background var(--transition), color var(--transition);
  white-space: nowrap;
}

.btn:hover { transform: translateY(-2px); }

.btn-primary {
  background: var(--color-primary);
  color: #fff;
  box-shadow: 0 4px 14px rgba(37,99,235,.3);
}
.btn-primary:hover {
  background: var(--color-primary-dark);
  box-shadow: 0 6px 20px rgba(37,99,235,.4);
}

.btn-outline {
  background: transparent;
  color: var(--color-text);
  border: 1.5px solid var(--color-border);
}
.btn-outline:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: rgba(37,99,235,.04);
}

.btn-white {
  background: #fff;
  color: var(--color-primary);
  font-weight: 700;
  box-shadow: 0 4px 14px rgba(0,0,0,.12);
}
.btn-white:hover {
  box-shadow: 0 6px 20px rgba(0,0,0,.2);
}

/* =============================================
   Header
   ============================================= */
.header {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--header-h);
  background: rgba(255,255,255,.85);
  backdrop-filter: blur(16px) saturate(180%);
  -webkit-backdrop-filter: blur(16px) saturate(180%);
  border-bottom: 1px solid var(--color-border);
  z-index: 100;
  transition: background var(--transition), border-color var(--transition);
}

[data-theme="dark"] .header {
  background: rgba(10,15,30,.88);
}

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

.logo {
  font-size: 1.125rem;
  font-weight: 800;
  color: var(--color-primary);
  letter-spacing: -.02em;
  line-height: 1;
}

.nav-desktop {
  display: flex;
  align-items: center;
  gap: 1.75rem;
}

.nav-link {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--color-text-muted);
  transition: color var(--transition);
}
.nav-link:hover { color: var(--color-primary); }

/* Theme toggle */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  width: 38px; height: 38px;
  background: var(--color-bg-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  color: var(--color-text-muted);
  cursor: pointer;
  overflow: hidden;
  transition: background 0.25s ease, color 0.25s ease,
              border-color 0.25s ease, box-shadow 0.25s ease;
}
.theme-toggle:hover {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 4px rgba(37,99,235,.15);
}
/* Active press feedback */
.theme-toggle:active { transform: scale(0.9); }

/* Icons: always in DOM, animated with opacity + rotation */
.theme-toggle .icon-sun,
.theme-toggle .icon-moon {
  position: absolute;
  transition: opacity 0.3s ease, transform 0.35s cubic-bezier(.34,1.56,.64,1);
}

/* Light mode: sun visible */
.theme-toggle .icon-sun  { opacity: 1; transform: rotate(0deg)   scale(1);   }
.theme-toggle .icon-moon { opacity: 0; transform: rotate(-90deg) scale(0.4); }

/* Hover in light mode: sun spins slightly */
.theme-toggle:hover .icon-sun { transform: rotate(30deg) scale(1.15); }

/* Dark mode: moon visible */
[data-theme="dark"] .theme-toggle .icon-sun  { opacity: 0; transform: rotate(90deg)  scale(0.4); }
[data-theme="dark"] .theme-toggle .icon-moon { opacity: 1; transform: rotate(0deg)   scale(1);   }

/* Hover in dark mode: moon rocks */
[data-theme="dark"] .theme-toggle:hover .icon-moon { transform: rotate(-20deg) scale(1.15); }

/* Mobile menu button */
.mobile-menu-btn {
  /*display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;*/
   display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
  overflow: visible;
  min-width: 34px;
}
.mobile-menu-btn span {
  display: block;
  width: 22px; height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}
.mobile-menu-btn.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.mobile-menu-btn.open span:nth-child(2) { opacity: 0; }
.mobile-menu-btn.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* Mobile nav */
.nav-mobile {
  display: none;
  flex-direction: column;
  gap: 0;
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  overflow: hidden;
  max-height: 0;
  transition: max-height 0.35s ease;
}
.nav-mobile.open { max-height: 320px; }
.nav-mobile .nav-link {
  padding: 0.9rem 1.5rem;
  border-bottom: 1px solid var(--color-border);
  font-size: 1rem;
}
.nav-mobile-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.9rem 1.5rem;
}

@media (max-width: 768px) {
  .nav-desktop     { display: none; }
  .mobile-menu-btn { display: flex; }
  .nav-mobile      { display: flex; }
}

/* =============================================
   Hero
   ============================================= */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: var(--header-h);
  overflow: hidden;
}

/* Subtle dot grid background */
.hero-bg-grid {
  position: absolute;
  inset: 0;
  background-image: radial-gradient(circle, var(--color-border) 1px, transparent 1px);
  background-size: 32px 32px;
  z-index: 0;
  opacity: 0.6;
}

.hero .container { position: relative; z-index: 1; }

.hero-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: center;
  padding: 5rem 0;
}

.hero-text {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 0.85rem;
  background: rgba(37,99,235,.1);
  color: var(--color-primary);
  border-radius: var(--radius-full);
  font-size: 0.8125rem;
  font-weight: 600;
  width: fit-content;
}
.hero-badge::before {
  content: '';
  display: block;
  width: 7px; height: 7px;
  background: #22c55e;
  border-radius: 50%;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50%       { opacity: .5; transform: scale(1.3); }
}

.hero-title {
  font-size: clamp(2.25rem, 5vw, 3.5rem);
  font-weight: 800;
  line-height: 1.12;
  letter-spacing: -0.03em;
  color: var(--color-text);
}

.highlight {
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--color-text-muted);
}

.hero-description {
  font-size: 1rem;
  color: var(--color-text-muted);
  line-height: 1.75;
  max-width: 480px;
}

.hero-buttons {
  display: flex;
  gap: 0.875rem;
  flex-wrap: wrap;
  margin-top: 0.5rem;
}

/* Profile image */
.hero-image {
  display: flex;
  justify-content: center;
  align-items: center;
}

.profile-ring {
  position: relative;
  width: clamp(260px, 35vw, 400px);
  height: clamp(260px, 35vw, 400px);
  border-radius: 50%;
  padding: 5px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  box-shadow: 0 20px 60px rgba(37,99,235,.25);
  flex-shrink: 0;
}

.profile-image {
  width: 100%; height: 100%;
  border-radius: 50%;
  object-fit: cover;
  border: 4px solid var(--color-bg);
  transition: transform 0.4s ease;
}
.profile-image:hover { transform: scale(1.03); }

/* Scroll hint */
.hero-scroll-hint {
  position: absolute;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  color: var(--color-text-muted);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: .08em;
  text-transform: uppercase;
  opacity: .6;
}

.scroll-dot { animation: scrollBob 1.8s ease-in-out infinite; }
@keyframes scrollBob {
  0%, 100% { transform: translateY(0); }
  50%       { transform: translateY(6px); }
}

/* Hero responsive */
@media (max-width: 900px) {
  .hero-content {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 2.5rem;
    padding: 3rem 0 5rem;
  }
  .hero-text { align-items: center; order: 2; }
  .hero-image { order: 1; }
  .hero-description { max-width: 540px; }
  .hero-buttons { justify-content: center; }
  .hero-badge { align-self: center; }
  .hero-scroll-hint { display: none; }
}

/* =============================================
   Section base
   ============================================= */
.section { padding: 6rem 0; }

.section-header {
  text-align: center;
  margin-bottom: 3.5rem;
}

.section-title {
  font-size: clamp(1.75rem, 3.5vw, 2.5rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 0.75rem;
}

.section-subtitle {
  font-size: 1rem;
  color: var(--color-text-muted);
  max-width: 520px;
  margin: 0 auto 2rem;
  line-height: 1.7;
}

/* =============================================
   Reveal animation
   ============================================= */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.55s ease, transform 0.55s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* =============================================
   Projects
   ============================================= */
.projects { background: var(--color-bg-2); }

/* Tab switcher */
.tab-switcher {
  display: inline-flex;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 5px;
  gap: 4px;
  box-shadow: var(--shadow-sm);
}

.tab-btn {
  padding: 0.5rem 1.35rem;
  border: none;
  background: transparent;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-text-muted);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background var(--transition), color var(--transition), box-shadow var(--transition);
}
.tab-btn:hover:not(.active) {
  background: var(--color-bg-2);
  color: var(--color-text);
}
.tab-btn.active {
  background: var(--color-primary);
  color: #fff;
  box-shadow: 0 3px 10px rgba(37,99,235,.3);
  animation: tabPop 0.3s cubic-bezier(.34,1.56,.64,1) both;
}

@keyframes tabPop {
  from { transform: scale(0.88); opacity: 0.6; }
  to   { transform: scale(1);    opacity: 1;   }
}

/* Projects grid — 2 columns on desktop */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.75rem;
  transition: opacity 0.18s ease, transform 0.18s ease;
}

/* Tab switch transition states */
.projects-grid.tab-exit {
  opacity: 0;
  transform: translateY(10px);
  pointer-events: none;
}
.projects-grid.tab-enter {
  animation: gridEnter 0.3s cubic-bezier(.22,1,.36,1) both;
}

@keyframes gridEnter {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0);    }
}

@media (max-width: 768px) {
  .projects-grid { grid-template-columns: 1fr; }
}

/* Project card */
.project-card {
  background: var(--color-bg);
  border-radius: var(--radius-xl);
  border: 1px solid var(--color-border);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}
.project-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
  border-color: rgba(37,99,235,.2);
}

.project-img-wrap {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16/9;
  background: var(--color-bg-2);
}
.project-img-wrap img {
  width: 100%; height: 100%;
  object-fit: cover;
  transition: transform 0.45s ease;
}
.project-card:hover .project-img-wrap img {
  transform: scale(1.04);
}

.project-img-placeholder {
  width: 100%; height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.5rem;
  color: var(--color-text-muted);
  opacity: 0.35;
}

.project-body {
  padding: 1.35rem 1.5rem 1.5rem;
  display: flex;
  flex-direction: column;
  flex: 1;
  gap: 0.6rem;
}

.project-tag {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .07em;
  color: var(--color-primary);
}

.project-title {
  font-size: 1.125rem;
  font-weight: 700;
  line-height: 1.3;
  color: var(--color-text);
}

.project-desc {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  line-height: 1.65;
  flex: 1;
}

.project-footer {
  margin-top: 1rem;
}

/* =============================================
   About
   ============================================= */
.about { background: var(--color-bg); }

.about-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.25rem;
  margin-bottom: 3rem;
}

.about-card {
  background: var(--color-bg-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: 1.5rem;
  transition: transform var(--transition), box-shadow var(--transition);
}
.about-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.about-card-icon {
  font-size: 1.5rem;
  margin-bottom: 0.75rem;
  line-height: 1;
}

.about-card-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 0.5rem;
}

.about-card-text {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  line-height: 1.7;
}

/* CTA block */
.about-cta {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
  border-radius: var(--radius-xl);
  padding: 3.5rem 2rem;
  text-align: center;
  color: #fff;
  position: relative;
  overflow: hidden;
}
.about-cta::before {
  content: '';
  position: absolute;
  inset: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.04'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

.cta-content { position: relative; z-index: 1; }
.cta-content h3 {
  font-size: clamp(1.4rem, 3vw, 2rem);
  font-weight: 800;
  margin-bottom: 0.6rem;
}
.cta-content p {
  font-size: 1rem;
  opacity: .9;
  margin-bottom: 1.5rem;
}

@media (max-width: 600px) {
  .about-grid { grid-template-columns: 1fr; }
  .about-cta { padding: 2.5rem 1.25rem; }
}

/* =============================================
   Footer
   ============================================= */
.footer {
  background: var(--color-bg-2);
  border-top: 1px solid var(--color-border);
  padding: 2.5rem 0;
}

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

.footer-brand {
  display: flex;
  align-items: center;
  gap: 1rem;
}
.footer-brand p {
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

.footer-copy {
  font-size: 0.8125rem;
  color: var(--color-text-muted);
}

@media (max-width: 480px) {
  .footer-inner { flex-direction: column; text-align: center; }
}

/* =============================================
   Utility
   ============================================= */
@media (max-width: 768px) {
  .section { padding: 4rem 0; }
}