:root {
  --color-bg: #0f172a;
  --color-bg-alt: #f8fafc;
  --color-surface: #ffffff;
  --color-text: #1e293b;
  --color-text-light: #64748b;
  --color-text-inverse: #f1f5f9;
  --color-accent: #2563eb;
  --color-accent-dark: #1d4ed8;
  --font-heading: 'Poppins', sans-serif;
  --font-body: 'Inter', sans-serif;
  --max-width: 1100px;
  --radius: 14px;
  --transition: 0.25s ease;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  color: var(--color-text);
  background: var(--color-bg-alt);
  line-height: 1.6;
}

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

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

h1, h2, h3 { font-family: var(--font-heading); line-height: 1.2; }

.section-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 6rem 1.5rem;
}

.section-label {
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-accent);
  margin-bottom: 0.75rem;
}

.center { text-align: center; margin-left: auto; margin-right: auto; }

.section-intro {
  max-width: 560px;
  color: var(--color-text-light);
  margin-top: 0.5rem;
  margin-bottom: 3rem;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.85rem 1.6rem;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
  transition: transform var(--transition), background var(--transition), color var(--transition);
  cursor: pointer;
  border: 2px solid transparent;
}
.btn:hover { transform: translateY(-2px); }

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

.btn-outline {
  border-color: rgba(255,255,255,0.6);
  color: #fff;
}
.btn-outline:hover { background: rgba(255,255,255,0.1); }

.icon { width: 20px; height: 20px; flex-shrink: 0; }

/* Header / nav */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: rgba(15, 23, 42, 0.85);
  backdrop-filter: blur(8px);
}

.navbar {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.1rem 1.5rem;
}

.logo {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.15rem;
  color: #fff;
}

.nav-links {
  list-style: none;
  display: flex;
  gap: 2rem;
}

.nav-links a {
  color: var(--color-text-inverse);
  font-weight: 500;
  font-size: 0.95rem;
  transition: color var(--transition);
}
.nav-links a:hover { color: var(--color-accent); }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}
.nav-toggle span {
  width: 24px;
  height: 2px;
  background: #fff;
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}

/* Hero */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 6rem 1.5rem 4rem;
  background: linear-gradient(160deg, #0f172a 0%, #1e293b 60%, #2563eb 140%);
  color: #fff;
}

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

.hero-eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.15em;
  font-size: 0.85rem;
  color: #93c5fd;
  margin-bottom: 1rem;
}

.hero h1 {
  font-size: clamp(2.5rem, 6vw, 4rem);
  font-weight: 700;
  margin-bottom: 1rem;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: #cbd5e1;
  margin-bottom: 2.5rem;
}

.hero-cta {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

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

.about-grid {
  display: grid;
  grid-template-columns: 320px 1fr;
  gap: 3.5rem;
  align-items: center;
}

.about-photo img {
  border-radius: var(--radius);
  box-shadow: 0 20px 40px -20px rgba(15, 23, 42, 0.3);
}

.about-text p { color: var(--color-text-light); margin-top: 1rem; }
.about-text h2 { font-size: 2rem; margin-bottom: 0.5rem; }

/* Portfolio */
.portfolio { background: var(--color-bg-alt); }

.portfolio h2 { font-size: 2rem; margin-bottom: 0.5rem; }

.activities {
  display: flex;
  flex-direction: column;
}

.activity {
  display: flex;
  align-items: center;
  gap: 4rem;
  padding: 4.5rem 0;
  border-bottom: 1px solid rgba(15, 23, 42, 0.08);
}
.activity:last-child { border-bottom: none; padding-bottom: 0; }
.activity:first-child { padding-top: 0; }

.activity.reverse { flex-direction: row-reverse; }

.activity-media { flex: 1 1 48%; min-width: 0; }
.activity-media img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  border-radius: var(--radius);
  box-shadow: 0 20px 40px -20px rgba(15, 23, 42, 0.3);
}

.activity-content { flex: 1 1 52%; }

.activity-index {
  display: block;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 2.75rem;
  color: rgba(37, 99, 235, 0.18);
  line-height: 1;
  margin-bottom: 0.5rem;
}

.activity-date {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-accent);
  margin-bottom: 0.4rem;
}

.activity-content h3 { font-size: 1.6rem; margin-bottom: 1rem; }
.activity-content p { color: var(--color-text-light); margin-bottom: 1rem; }

.activity-reflection {
  margin-top: 1.5rem;
  padding-top: 1.25rem;
  border-top: 1px solid rgba(15, 23, 42, 0.08);
}

.activity-reflection h4 {
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.75rem;
  color: var(--color-text-light);
  margin-bottom: 0.75rem;
}

.activity-reflection ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.activity-reflection li {
  font-size: 0.92rem;
  color: var(--color-text-light);
}

.activity-reflection li strong { color: var(--color-text); }

/* Contact */
.contact {
  background: linear-gradient(160deg, #0f172a 0%, #1e293b 100%);
  color: #fff;
}

.contact-grid { display: flex; justify-content: center; }
.contact-info { max-width: 520px; width: 100%; }
.contact-info h2 { font-size: 2rem; margin-bottom: 2rem; }

.contact-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  margin-bottom: 2.5rem;
}

.contact-list li {
  display: flex;
  align-items: center;
  gap: 0.9rem;
  color: #cbd5e1;
}

.contact-list a:hover { color: var(--color-accent); }

.cv-download { width: fit-content; }

/* Footer */
.site-footer {
  background: #0b1120;
  color: #94a3b8;
  text-align: center;
  padding: 2rem 1.5rem;
  font-size: 0.85rem;
}

/* Responsive */
@media (max-width: 800px) {
  .about-grid { grid-template-columns: 1fr; text-align: center; }
  .about-photo { max-width: 260px; margin: 0 auto; }

  .activity,
  .activity.reverse {
    flex-direction: column;
    gap: 2rem;
    padding: 3rem 0;
  }

  .nav-toggle { display: flex; }

  .nav-links {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    background: #0f172a;
    padding: 1.5rem;
    gap: 1.25rem;
    transform: translateY(-150%);
    opacity: 0;
    transition: transform var(--transition), opacity var(--transition);
  }

  .nav-links.open {
    transform: translateY(0);
    opacity: 1;
  }
}