:root {
  --slate: #2c3e50;
  --slate-light: #34495e;
  --teal: #1abc9c;
  --teal-dark: #16a085;
  --white: #ffffff;
  --gray-light: #ecf0f1;
  --text: #bdc3c7;
  --font: "Inter", system-ui, -apple-system, sans-serif;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font);
  background: var(--slate);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--teal);
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: var(--teal-dark);
}

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

/* Hero */
.hero {
  min-height: 80vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 4rem 1.5rem;
  background: linear-gradient(
    135deg,
    var(--slate) 0%,
    var(--slate-light) 100%
  );
}

.hero-photo {
  width: 160px;
  height: 160px;
  border-radius: 50%;
  object-fit: cover;
  border: 4px solid var(--teal);
  margin-bottom: 1.5rem;
}

.hero h1 {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--white);
  margin-bottom: 0.5rem;
}

.hero .subtitle {
  font-size: 1.15rem;
  color: var(--text);
  margin-bottom: 1.5rem;
}

.social-links {
  display: flex;
  gap: 1rem;
  list-style: none;
}

.social-links a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border: 2px solid var(--teal);
  border-radius: 50%;
  color: var(--teal);
  transition: background 0.2s, color 0.2s;
}

.social-links a:hover {
  background: var(--teal);
  color: var(--white);
}

.social-links svg {
  width: 20px;
  height: 20px;
  fill: currentColor;
}

/* Sections */
section {
  padding: 5rem 1.5rem;
  max-width: 960px;
  margin: 0 auto;
}

.section-title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--white);
  margin-bottom: 1.5rem;
}

/* About */
.about {
  border-top: 4px solid var(--teal);
}

.about p {
  font-size: 1.05rem;
  max-width: 720px;
}

/* Books */
.books {
  max-width: 1100px;
}

.book-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 1.5rem;
  list-style: none;
}

.book-grid li {
  position: relative;
  overflow: hidden;
  border-radius: 6px;
  background: var(--slate-light);
}

.book-grid img {
  width: 100%;
  aspect-ratio: 3 / 4;
  object-fit: cover;
  transition: transform 0.3s, opacity 0.3s;
}

.book-grid li:hover img {
  transform: scale(1.05);
  opacity: 0.3;
}

.book-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  text-align: center;
  opacity: 0;
  transition: opacity 0.3s;
}

.book-grid li:hover .book-overlay {
  opacity: 1;
}

.book-overlay h3 {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--white);
  margin-bottom: 0.75rem;
}

.book-overlay a {
  display: inline-block;
  padding: 0.4rem 1rem;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--white);
  background: var(--teal);
  border-radius: 4px;
  transition: background 0.2s;
}

.book-overlay a:hover {
  background: var(--teal-dark);
  color: var(--white);
}

/* Footer */
footer {
  text-align: center;
  padding: 3rem 1.5rem;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  font-size: 0.9rem;
  color: var(--text);
}

footer a {
  color: var(--teal);
}

/* Nav */
nav {
  position: fixed;
  top: 0;
  width: 100%;
  z-index: 100;
  background: rgba(44, 62, 80, 0.95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  padding: 0.75rem 1.5rem;
  display: flex;
  justify-content: center;
  gap: 2rem;
}

nav a {
  color: var(--text);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.2s;
}

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

/* Responsive */
@media (max-width: 600px) {
  .hero h1 {
    font-size: 1.8rem;
  }

  .hero .subtitle {
    font-size: 1rem;
  }

  .book-grid {
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: 1rem;
  }

  section {
    padding: 3rem 1rem;
  }

  nav {
    gap: 1rem;
    padding: 0.6rem 1rem;
  }

  nav a {
    font-size: 0.8rem;
  }
}