/* Reset and Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --primary-color: #1a73e8;
  --accent-color: #ffd54f;
  --text-dark: #212121;
  --text-light: #757575;
  --bg-white: #ffffff;
  --bg-light: #f5f5f5;
  --border-radius: 8px;
  --transition: all 0.3s ease;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: "Inter", sans-serif;
  color: var(--text-dark);
  line-height: 1.6;
  background-color: var(--bg-white);
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: "Poppins", sans-serif;
  font-weight: 600;
  line-height: 1.2;
}

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

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

/* Skip Link for Accessibility */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--primary-color);
  color: white;
  padding: 8px 16px;
  z-index: 100;
  border-radius: 0 0 var(--border-radius) 0;
}

.skip-link:focus {
  top: 0;
}

/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Header */
.header {
  background: var(--bg-white);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  position: sticky;
  top: 0;
  z-index: 1000;
  padding: 16px 0;
}

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

.logo a {
  font-family: "Poppins", sans-serif;
  font-size: 24px;
  font-weight: 700;
  color: var(--primary-color);
}

.nav-list {
  display: flex;
  gap: 32px;
  list-style: none;
}

.nav-link {
  font-weight: 500;
  color: var(--text-dark);
  transition: var(--transition);
  position: relative;
}

.nav-link:hover,
.nav-link.active {
  color: var(--primary-color);
}

.nav-link.active::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 100%;
  height: 2px;
  background: var(--primary-color);
}

.header-cta {
  display: inline-block;
}

/* Burger Menu */
.burger {
  display: none;
  flex-direction: column;
  gap: 4px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.burger-line {
  width: 24px;
  height: 3px;
  background: var(--text-dark);
  transition: var(--transition);
  border-radius: 2px;
}

.burger.active .burger-line:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.burger.active .burger-line:nth-child(2) {
  opacity: 0;
}

.burger.active .burger-line:nth-child(3) {
  transform: rotate(-45deg) translate(7px, -6px);
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 12px 24px;
  border-radius: var(--border-radius);
  font-weight: 500;
  transition: var(--transition);
  cursor: pointer;
  border: none;
  font-family: "Inter", sans-serif;
  font-size: 16px;
  text-align: center;
}

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

.btn-primary:hover {
  background: #1557b0;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(26, 115, 232, 0.3);
}

.btn-secondary {
  background: var(--bg-light);
  color: var(--text-dark);
}

.btn-secondary:hover {
  background: #e0e0e0;
}

.btn-large {
  padding: 16px 32px;
  font-size: 18px;
}

.btn-small {
  padding: 8px 16px;
  font-size: 14px;
}

/* Hero Section */
.hero {
  padding: 80px 0;
  background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
}

.hero .container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.hero-title {
  font-size: 48px;
  margin-bottom: 20px;
  color: var(--text-dark);
}

.hero-subtitle {
  font-size: 20px;
  color: var(--text-light);
  margin-bottom: 32px;
}

.hero-buttons {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

/* About Section */
.about {
  padding: 80px 0;
}

.section-header {
  text-align: center;
  margin-bottom: 60px;
}

.section-title {
  font-size: 40px;
  margin-bottom: 16px;
}

.section-subtitle {
  font-size: 18px;
  color: var(--text-light);
}

.about-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.about-text p {
  margin-bottom: 20px;
  font-size: 18px;
  line-height: 1.8;
}

/* Features Section */
.features {
  padding: 80px 0;
  background: var(--bg-light);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.feature-card {
  background: white;
  padding: 32px;
  border-radius: var(--border-radius);
  transition: var(--transition);
}

.feature-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
}

.feature-icon {
  font-size: 48px;
  margin-bottom: 16px;
}

.feature-title {
  font-size: 22px;
  margin-bottom: 12px;
}

.feature-description {
  color: var(--text-light);
  line-height: 1.6;
}

/* Testimonials Section */
.testimonials {
  padding: 80px 0;
}

.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.testimonial-card {
  background: var(--bg-light);
  padding: 32px;
  border-radius: var(--border-radius);
}

.testimonial-content {
  margin-bottom: 24px;
  font-style: italic;
  color: var(--text-dark);
  line-height: 1.8;
}

.testimonial-author {
  display: flex;
  align-items: center;
  gap: 16px;
}

.author-name {
  font-size: 16px;
  margin-bottom: 4px;
}

.author-role {
  font-size: 14px;
  color: var(--text-light);
}

/* Use Cases Section */
.use-cases {
  padding: 80px 0;
  background: var(--bg-light);
}

.use-cases-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.use-case-card {
  background: white;
  border-radius: var(--border-radius);
  overflow: hidden;
  transition: var(--transition);
}

.use-case-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
}

.use-case-content {
  position: relative;
  padding: 24px;
  background-color: #fff;
  z-index: 2;
}

.use-case-title {
  font-size: 22px;
  margin-bottom: 12px;
}

.use-case-description {
  color: var(--text-light);
  line-height: 1.6;
}

/* Contact Section */
.contact {
  padding: 80px 0;
}

.contact-content {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 60px;
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.form-label {
  font-weight: 500;
  color: var(--text-dark);
}

.form-input,
.form-textarea {
  padding: 12px 16px;
  border: 2px solid #e0e0e0;
  border-radius: var(--border-radius);
  font-family: "Inter", sans-serif;
  font-size: 16px;
  transition: var(--transition);
}

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

.form-textarea {
  resize: vertical;
  min-height: 120px;
}

.form-error {
  color: #d32f2f;
  font-size: 14px;
  display: none;
}

.form-error.show {
  display: block;
}

.form-success {
  background: #4caf50;
  color: white;
  padding: 16px;
  border-radius: var(--border-radius);
  display: none;
}

.form-success.show {
  display: block;
}

.contact-info {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.info-card {
  background: var(--bg-light);
  padding: 24px;
  border-radius: var(--border-radius);
  display: flex;
  flex-direction: column;
}

.info-card h3 {
  margin-bottom: 12px;
  color: var(--primary-color);
}

.info-card p,
a {
  color: var(--text-light);
  line-height: 1.8;
}

/* Footer */
.footer {
  background: var(--text-dark);
  color: white;
  padding: 60px 0 20px;
}

.footer-content {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-title {
  font-size: 24px;
  margin-bottom: 16px;
  color: var(--accent-color);
}

.footer-description {
  color: #b0b0b0;
  line-height: 1.8;
  margin-bottom: 20px;
}

.social-links {
  display: flex;
  gap: 16px;
}

.social-link {
  width: 40px;
  height: 40px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
}

.social-link:hover {
  background: var(--primary-color);
  transform: translateY(-4px);
}

.footer-heading {
  font-size: 18px;
  margin-bottom: 16px;
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-links a {
  color: #b0b0b0;
  transition: var(--transition);
}

.footer-links a:hover {
  color: var(--accent-color);
}

.footer-bottom {
  display: flex;
  flex-direction: column;
  text-align: center;
  padding-top: 20px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  color: #b0b0b0;
}

/* Page Hero (for subpages) */
.page-hero {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  padding: 80px 0;
  text-align: center;
  color: white;
}

.page-title {
  font-size: 48px;
  margin-bottom: 16px;
}

.page-subtitle {
  font-size: 20px;
  opacity: 0.9;
}

/* Catalog Section */
.catalog-section {
  padding: 60px 0;
}

.catalog-filters {
  margin-bottom: 40px;
}

.search-bar {
  display: flex;
  gap: 16px;
  margin-bottom: 24px;
}

.search-input {
  flex: 1;
  padding: 12px 16px;
  border: 2px solid #e0e0e0;
  border-radius: var(--border-radius);
  font-family: "Inter", sans-serif;
  font-size: 16px;
}

.filter-buttons {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.filter-btn {
  padding: 8px 20px;
  background: var(--bg-light);
  border: 2px solid transparent;
  border-radius: var(--border-radius);
  cursor: pointer;
  font-family: "Inter", sans-serif;
  font-size: 14px;
  font-weight: 500;
  transition: var(--transition);
}

.filter-btn:hover,
.filter-btn.active {
  background: var(--primary-color);
  color: white;
}

.catalog-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.book-card {
  background: white;
  border-radius: var(--border-radius);
  overflow: hidden;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  transition: var(--transition);
}

.book-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
}

.book-info {
  padding: 20px;
}

.book-title {
  font-size: 18px;
  margin-bottom: 8px;
}

.book-author {
  color: var(--text-light);
  font-size: 14px;
  margin-bottom: 12px;
}

.book-status {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 12px;
  font-size: 12px;
  font-weight: 500;
  margin-bottom: 12px;
}

.book-status.available {
  background: #e8f5e9;
  color: #2e7d32;
}

.book-status.checked-out {
  background: #ffebee;
  color: #c62828;
}

.book-status.digital {
  background: #e3f2fd;
  color: #1565c0;
}

/* Services Detail Section */
.services-detail {
  padding: 60px 0;
}

.service-item {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
  margin-bottom: 80px;
}

.service-item.reverse {
  direction: rtl;
}

.service-item.reverse > * {
  direction: ltr;
}

.service-heading {
  font-size: 32px;
  margin-bottom: 20px;
}

.service-text {
  font-size: 18px;
  color: var(--text-light);
  line-height: 1.8;
  margin-bottom: 20px;
}

.service-list {
  list-style: none;
  margin-bottom: 24px;
}

.service-list li {
  padding: 8px 0;
  padding-left: 28px;
  position: relative;
  color: var(--text-dark);
}

.service-list li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--primary-color);
  font-weight: bold;
}

/* Code Snippet */
.code-snippet {
  background: #1e1e1e;
  border-radius: var(--border-radius);
  overflow: hidden;
  margin-top: 24px;
}

.code-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 16px;
  background: #2d2d2d;
  color: white;
  font-size: 14px;
}

.copy-btn {
  background: var(--primary-color);
  color: white;
  border: none;
  padding: 6px 12px;
  border-radius: 4px;
  cursor: pointer;
  font-size: 12px;
  transition: var(--transition);
}

.copy-btn:hover {
  background: #1557b0;
}

.copy-btn.copied {
  background: #4caf50;
}

.code-content {
  padding: 16px;
  color: #d4d4d4;
  font-family: "Courier New", monospace;
  font-size: 14px;
  line-height: 1.6;
  overflow-x: auto;
}

/* Animations */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Responsive Design */
@media (max-width: 992px) {
  .hero .container,
  .about-content,
  .contact-content,
  .service-item {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .features-grid,
  .testimonials-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .use-cases-grid,
  .catalog-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .footer-content {
    grid-template-columns: 1fr 1fr;
  }

  .hero-title {
    font-size: 40px;
  }

  .section-title {
    font-size: 36px;
  }
}

@media (max-width: 767px) {
  .nav {
    position: fixed;
    top: 72px;
    left: 0;
    right: 0;
    background: white;
    padding: 20px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    transform: translateY(-100%);
    opacity: 0;
    transition: var(--transition);
  }

  .nav.active {
    transform: translateY(0);
    opacity: 1;
  }

  .nav-list {
    flex-direction: column;
    gap: 16px;
  }

  .header-cta {
    display: none;
  }

  .burger {
    display: flex;
    position: relative;
    z-index: 2;
  }

  .hero-title {
    font-size: 32px;
  }

  .hero-subtitle {
    font-size: 18px;
  }

  .section-title {
    font-size: 28px;
  }

  .features-grid,
  .testimonials-grid,
  .use-cases-grid,
  .catalog-grid {
    grid-template-columns: 1fr;
  }

  .footer-content {
    grid-template-columns: 1fr;
  }

  .hero-buttons {
    flex-direction: column;
  }

  .btn-large {
    width: 100%;
  }

  .page-title {
    font-size: 36px;
  }

  .service-item.reverse {
    direction: ltr;
  }
}