/* Reset dan variabel */
:root {
  --primary-color: #2c3e50;
  --secondary-color: #e74c3c;
  --accent-color: #f39c12;
  --light-color: #ecf0f1;
  --dark-color: #2c3e50;
  --text-color: #333;
  --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
}

html {
  scroll-behavior: smooth;
  overflow-x: hidden;
}

body {
  background-color: #f9f9f9;
  color: var(--text-color);
  line-height: 1.6;
  overflow-x: hidden;
}

/* Header dan Navigasi */
header {
  background-color: var(--primary-color);
  color: white;
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow);
}

.container {
  width: 90%;
  max-width: 1200px;
  margin: 0 auto;
}

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

.logo {
  font-size: 1.5rem;
  font-weight: bold;
  color: white;
  text-decoration: none;
}

.logo span {
  color: var(--accent-color);
}

nav ul {
  display: flex;
  list-style: none;
}

nav ul li {
  margin-left: 1.5rem;
  display: flex;
  align-items: center;
}

nav ul li a {
  color: white;
  text-decoration: none;
  font-weight: 500;
  transition: color 0.3s;
}

nav ul li a:hover {
  color: var(--accent-color);
}

/* Content Styles */
.page-header {
  background: linear-gradient(rgba(0, 0, 0, 0.4), rgba(0, 0, 0, 0.6)), url(../img/background1.png) no-repeat center center / cover, var(--primary-color);
  color: white;
  padding: 6rem 0;
  text-align: center;
  min-height: 450px;
  align-content: center;
}

.hero-content {
  max-width: 800px;
  margin: 0 auto;
}

.hero h1 {
  font-size: 3rem;
  margin-bottom: 1rem;
  line-height: 1.2;
}

.hero p {
  font-size: 1.2rem;
  margin-bottom: 2rem;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.cta-button {
  display: inline-block;
  background-color: var(--secondary-color);
  color: white;
  padding: 0.8rem 2rem;
  border-radius: 30px;
  text-decoration: none;
  font-weight: bold;
  font-size: 1.1rem;
  transition: all 0.3s;
  box-shadow: var(--shadow);
}

.cta-button:hover {
  background-color: #c0392b;
  transform: translateY(-3px);
}

.cti-button {
  display: inline-block;
  background-color: transparent;
  border: solid 2px var(--accent-color);
  color: white;
  padding: 0.8rem 2rem;
  border-radius: 30px;
  text-decoration: none;
  font-weight: bold;
  font-size: 1.1rem;
  transition: all 0.3s;
  box-shadow: var(--shadow);
}

.cti-button:hover {
  background-color: var(--accent-color);
  transform: translateY(-3px);
}

/* Features Section */
.features {
  padding: 5rem 0;
  background-color: white;
}

.section-title {
  text-align: center;
  margin-bottom: 3rem;
}

.section-title h2 {
  font-size: 2.5rem;
  color: var(--primary-color);
  margin-bottom: 1rem;
}

.section-title p {
  color: #666;
  max-width: 600px;
  margin: 0 auto;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
}

.feature-card {
  background-color: var(--light-color);
  border-radius: 10px;
  padding: 2rem;
  text-align: center;
  box-shadow: var(--shadow);
  transition: transform 0.3s;
}

.feature-card:hover {
  transform: translateY(-10px);
}

.feature-icon {
  font-size: 3rem;
  color: var(--secondary-color);
  margin-bottom: 1rem;
}

.feature-card h3 {
  margin-bottom: 1rem;
  color: var(--primary-color);
}

/* Ebook Preview */
.ebook-preview {
  padding: 5rem 0;
  background-color: #f5f5f5;
}

.preview-container {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
}

.preview-image {
  flex: 1;
  min-width: 300px;
  text-align: center;
}

.preview-image img {
  max-width: 100%;
  max-height: 340px;
  width: auto;
  height: auto;
  border-radius: 10px;
  object-fit: contain;
}

.preview-content {
  flex: 1;
  min-width: 300px;
}

.preview-content h2 {
  font-size: 2.2rem;
  margin-bottom: 1.5rem;
  color: var(--primary-color);
}

.preview-content p {
  text-align: justify;
  margin-bottom: 1.5rem;
}

.preview-buttons {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  justify-content: center;
}

.btn {
  display: inline-block;
  padding: 0.8rem 1.5rem;
  border-radius: 5px;
  text-decoration: none;
  font-weight: bold;
  transition: all 0.3s;
}

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

.btn-primary:hover {
  background-color: #c0392b;
}

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

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

/* Footer */
footer {
  background-color: var(--primary-color);
  color: white;
  padding: 3rem 0 1.5rem;
}

.footer-content {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 2rem;
  margin-bottom: 2rem;
}

.footer-section {
  flex: 1;
  min-width: 250px;
}

.footer-section h3 {
  margin-bottom: 1.5rem;
  font-size: 1.2rem;
}

.footer-section ul {
  list-style: none;
}

.footer-section ul li {
  margin-bottom: 0.8rem;
}

.footer-section ul li a {
  color: #ddd;
  text-decoration: none;
  transition: color 0.3s;
}

.footer-section ul li a:hover {
  color: var(--accent-color);
}

.copyright {
  text-align: center;
  padding-top: 1.5rem;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  font-size: 0.9rem;
  color: #ddd;
}

/* Hamburger Menu Styles */
.hamburger {
  display: none;
  flex-direction: column;
  cursor: pointer;
  width: 32px;
  height: 32px;
  justify-content: center;
  align-items: center;
  z-index: 200;
}
.hamburger span {
  display: block;
  height: 4px;
  width: 100%;
  background: white;
  margin: 4px 0;
  border-radius: 2px;
  transition: all 0.3s;
}

/* Hamburger active animation */
.hamburger.active span:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
}
.hamburger.active span:nth-child(2) {
  opacity: 0;
}
.hamburger.active span:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}

/* Additional styles specific to sumber.html */
.sources-section {
  padding: 5rem 0;
  background-color: white;
}

.sources-category {
  margin-bottom: 4rem;
}

.category-title {
  font-size: 1.8rem;
  color: var(--primary-color);
  margin-bottom: 1.5rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--accent-color);
}

.sources-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: 2rem;
  margin-top: 2rem;
}

.source-card {
  background-color: var(--light-color);
  border-radius: 10px;
  padding: 2rem;
  box-shadow: var(--shadow);
  transition: transform 0.3s;
  border-left: 4px solid var(--secondary-color);
  display: flex;
  flex-direction: column;
  height: 100%;
}

.source-card:hover {
  transform: translateY(-5px);
}

.source-title {
  font-size: 1.3rem;
  color: var(--primary-color);
  margin-bottom: 1rem;
  line-height: 1.4;
  flex-grow: 1;
}

.source-link {
  display: inline-block;
  background-color: var(--secondary-color);
  color: white;
  padding: 0.6rem 1.2rem;
  border-radius: 5px;
  text-decoration: none;
  font-weight: bold;
  margin-top: 1rem;
  transition: all 0.3s;
  text-align: center;
}

.source-link:hover {
  background-color: #c0392b;
  transform: translateY(-2px);
}

.source-meta {
  color: #666;
  font-size: 0.9rem;
  margin-top: 0.5rem;
}

.video-container {
  position: relative;
  width: 100%;
  height: 0;
  padding-bottom: 56.25%; /* 16:9 aspect ratio */
  margin-bottom: 1rem;
  border-radius: 8px;
  overflow: hidden;
}

.video-container iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: none;
}

.video-card {
  grid-column: 1 / -1;
  max-width: 800px;
  margin: 0 auto;
}

/* Responsive */
@media (max-width: 1300px) {
  header {
    padding: 1.2rem 0;
  }
  .logo {
    font-size: 1.2rem;
  }
}

@media (max-width: 1150px) {
  .logo {
    font-size: 0.9rem;
  }
  .nav-container {
    flex-direction: row;
    align-items: center;
  }
  .hamburger {
    display: flex;
  }
  nav {
    position: absolute;
    top: 70px;
    right: 0;
    background: var(--primary-color);
    width: 220px;
    box-shadow: var(--shadow);
    border-radius: 0 0 0 12px;
    transform: translateX(100%);
    transition: transform 0.3s;
    z-index: 150;
  }
  nav.active {
    transform: translateX(0);
  }
  nav ul {
    flex-direction: column;
    align-items: flex-start;
    padding: 1.5rem 1rem;
    margin: 0;
    gap: 1rem;
  }
  nav ul li {
    margin: 0;
    width: 100%;
  }
  .cta-button,
  .cti-button {
    padding: 0.6rem 0.8rem;
  }
}

/* Extra Responsive for mobile */
@media (max-width: 600px) {
  .preview-image img {
    max-height: 180px;
  }
  .container {
    width: 98%;
    padding: 0 5px;
  }
  .page-header {
    background: linear-gradient(rgba(0, 0, 0, 0.4), rgba(0, 0, 0, 0.6)),
      url("../img/background2.png") no-repeat center center/cover,
      var(--primary-color);
  }
  .hero h1 {
    font-size: 1.5rem;
  }
  .section-title h2 {
    font-size: 1.3rem;
  }
  .preview-content h2 {
    font-size: 1.1rem;
  }
  .sources-section {
    padding: 2rem 0;
  }
  .sources-category {
    margin-bottom: 2rem;
  }
  .category-title {
    font-size: 1.1rem;
    padding-bottom: 0.2rem;
  }
  .sources-grid {
    grid-template-columns: 1fr;
    gap: 1rem;
    margin-top: 1rem;
  }
  .source-card {
    padding: 0.8rem;
    font-size: 0.95rem;
  }
  .source-title {
    font-size: 1rem;
  }
  .source-link {
    padding: 0.5rem 1rem;
    font-size: 0.95rem;
  }
  .video-card {
    max-width: 100%;
    margin: 0;
  }
  .video-container {
    border-radius: 4px;
  }
  .footer-content {
    flex-direction: column;
    gap: 1rem;
  }
}