:root {
  --bg:        #ffffff;
  --bg-alt:    #f8f9fa;
  --text:      #0f172a;
  --text-light:#475569;
  --primary:   #6366f1;
  --primary-dark: #4f46e5;
  --border:    #e2e8f0;
  --card:      #ffffff;
}

[data-theme="dark"] {
  --bg:        #0f172a;
  --bg-alt:    #1e293b;
  --text:      #e2e8f0;
  --text-light:#94a3b8;
  --primary:   #818cf8;
  --primary-dark:#6366f1;
  --border:    #334155;
  --card:      #1e293b;
}

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

html, body {
  font-family: 'Inter', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  transition: background 0.4s, color 0.4s;
}

body {
  line-height: 1.6;
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

header {
  padding: 24px 0;
  position: sticky;
  top: 0;
  background: var(--bg);
  z-index: 100;
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(12px);
}

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

.logo {
  font-weight: 700;
  font-size: 1.5rem;
}

.tech {
  color: var(--primary);
}

nav a {
  margin-left: 32px;
  color: var(--text-light);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.2s;
}

nav a:hover {
  color: var(--text);
}

#theme-toggle {
  position: fixed;
  top: 20px;
  right: 24px;
  z-index: 200;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 50%;
  width: 48px;
  height: 48px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  transition: all 0.3s;
  box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}

[data-theme="dark"] #theme-toggle {
  box-shadow: 0 4px 16px rgba(0,0,0,0.4);
}

#theme-toggle .sun,
#theme-toggle .moon {
  transition: opacity 0.4s, transform 0.4s;
}

[data-theme="light"] .sun { opacity: 1; transform: rotate(0deg); }
[data-theme="light"] .moon { opacity: 0; transform: rotate(-90deg); }
[data-theme="dark"]  .sun { opacity: 0; transform: rotate(90deg); }
[data-theme="dark"]  .moon { opacity: 1; transform: rotate(0deg); }

#hero {
  padding: 140px 0 100px;
  text-align: center;
}

h1 {
  font-size: clamp(3.2rem, 8vw, 5.5rem);
  font-weight: 700;
  line-height: 0.95;
  margin-bottom: 1.2rem;
}

.wave {
  display: inline-block;
  animation: wave 2.5s infinite;
  transform-origin: 70% 70%;
}

@keyframes wave {
  0%, 100% { transform: rotate(0deg); }
  20% { transform: rotate(20deg); }
  40% { transform: rotate(-15deg); }
  60% { transform: rotate(15deg); }
  80% { transform: rotate(-10deg); }
}

.lead {
  font-size: 1.38rem;
  color: var(--text-light);
  margin: 1.5rem 0 2.5rem;
  line-height: 1.5;
}

.cta-buttons {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  padding: 14px 28px;
  border-radius: 8px;
  font-weight: 600;
  text-decoration: none;
  transition: all 0.25s;
}

.btn.primary {
  background: var(--primary);
  color: white;
}

.btn.primary:hover {
  background: var(--primary-dark);
  transform: translateY(-1px);
}

.btn.outline {
  border: 2px solid var(--primary);
  color: var(--primary);
}

.btn.outline:hover {
  background: var(--primary);
  color: white;
}

.btn.large {
  padding: 18px 36px;
  font-size: 1.15rem;
}

section {
  padding: 100px 0;
}

h2 {
  font-size: 2.8rem;
  margin-bottom: 3rem;
  text-align: center;
}

.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: center;
}

.tech-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.tech-tags span {
  background: var(--bg-alt);
  padding: 8px 14px;
  border-radius: 6px;
  font-size: 0.9rem;
  border: 1px solid var(--border);
}

.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 2rem;
}

.project-card {
  background: var(--card);
  padding: 2rem;
  border-radius: 12px;
  border: 1px solid var(--border);
  transition: transform 0.25s, box-shadow 0.25s;
}

.project-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 20px 40px rgba(0,0,0,0.12);
}

[data-theme="dark"] .project-card:hover {
  box-shadow: 0 20px 40px rgba(0,0,0,0.5);
}

.project-card h3 {
  margin-bottom: 1rem;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 1.5rem;
}

.tags span {
  font-size: 0.82rem;
  background: var(--bg-alt);
  padding: 5px 12px;
  border-radius: 6px;
  border: 1px solid var(--border);
}

.alt-bg {
  background: var(--bg-alt);
}

.contact-lead {
  text-align: center;
  font-size: 1.25rem;
  color: var(--text-light);
  margin: 1.5rem 0 2.5rem;
}

footer {
  padding: 60px 0 40px;
  text-align: center;
  color: var(--text-light);
  border-top: 1px solid var(--border);
}

@media (max-width: 768px) {
  header .container { flex-direction: column; gap: 16px; }
  nav a { margin: 0 16px; font-size: 0.95rem; }
  .about-grid { grid-template-columns: 1fr; }
  #hero { padding: 100px 0 80px; }
  h1 { font-size: 3.8rem; }
}