:root {
  --color-bg: #ffffff;
  --color-bg-alt: #f6f7f9;
  --color-text: #1a1a1a;
  --color-text-muted: #5a5a5a;
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-border: #e5e7eb;
  --max-width: 1100px;
  --radius: 10px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #111318;
    --color-bg-alt: #1a1d24;
    --color-text: #f2f2f2;
    --color-text-muted: #a8adb8;
    --color-border: #2a2e37;
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.6;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--color-text);
  text-decoration: none;
}

.main-nav {
  display: flex;
  gap: 28px;
}

.main-nav a {
  color: var(--color-text-muted);
  text-decoration: none;
  font-size: 0.95rem;
  transition: color 0.15s ease;
}

.main-nav a:hover { color: var(--color-primary); }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.nav-toggle span {
  width: 22px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
}

/* Hero */
.hero {
  padding: 120px 0 90px;
  text-align: center;
  background: linear-gradient(180deg, var(--color-bg-alt), var(--color-bg));
}

.hero-eyebrow {
  color: var(--color-primary);
  font-weight: 600;
  letter-spacing: 0.03em;
  margin: 0 0 8px;
}

.hero h1 {
  font-size: clamp(2.2rem, 5vw, 3.5rem);
  margin: 0 0 12px;
}

.hero-subtitle {
  color: var(--color-text-muted);
  font-size: 1.15rem;
  margin: 0 0 32px;
}

.hero-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  padding: 12px 26px;
  border-radius: var(--radius);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.15s ease, background 0.15s ease;
}

.btn:hover { transform: translateY(-1px); }

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

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

.btn-secondary {
  background: transparent;
  color: var(--color-text);
  border-color: var(--color-border);
}

/* Sections */
.section {
  padding: 80px 0;
}

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

.section-title {
  font-size: 1.8rem;
  margin: 0 0 20px;
}

.section-text {
  color: var(--color-text-muted);
  max-width: 700px;
}

/* Skills */
.skills-grid {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
}

.skill-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 20px;
  text-align: center;
  font-weight: 600;
}

/* Projects */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
}

.project-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 24px;
}

.project-card h3 {
  margin: 0 0 10px;
}

.project-card p {
  color: var(--color-text-muted);
  margin: 0 0 16px;
}

.project-link {
  color: var(--color-primary);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.9rem;
}

/* Contact form */
.contact-form {
  max-width: 520px;
  display: flex;
  flex-direction: column;
  gap: 18px;
  margin-top: 24px;
}

.form-row {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.form-row label {
  font-size: 0.9rem;
  font-weight: 600;
}

.form-row input,
.form-row textarea {
  padding: 12px 14px;
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
  background: var(--color-bg);
  color: var(--color-text);
  font-family: inherit;
  font-size: 0.95rem;
}

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

.form-note {
  font-size: 0.9rem;
  color: var(--color-primary);
  min-height: 1.2em;
}

/* Footer */
.site-footer {
  padding: 32px 0;
  border-top: 1px solid var(--color-border);
  text-align: center;
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

/* Responsive nav */
@media (max-width: 720px) {
  .nav-toggle { display: flex; }

  .main-nav {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    padding: 16px 24px;
    gap: 16px;
    display: none;
  }

  .main-nav.open { display: flex; }
}