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

:root {
  --dark-blue: #0a1929;
  --dark-blue-light: #132f4c;
  --dark-blue-lighter: #1e4976;
  --accent-blue: #1976d2;
  --accent-blue-light: #42a5f5;
  --text-primary: #ffffff;
  --text-secondary: #b0bec5;
  --text-muted: #78909c;
  --border-color: #1e4976;
  --hover-bg: #1e4976;
}

html {
  overflow-x: hidden;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background-color: var(--dark-blue);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  width: 100%;
}

/* Header Styles */
header {
  background-color: var(--dark-blue-light);
  border-bottom: 1px solid var(--border-color);
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

.header-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 2rem;
  position: relative;
}

.header-logo {
  display: flex;
  align-items: center;
  text-decoration: none;
  flex-shrink: 0;
  background-color: var(--accent-blue-light);
  padding: 0.5rem 1rem;
  border-radius: 8px;
  transition: background-color 0.3s ease;
}

.header-logo:hover {
  background-color: var(--accent-blue);
}

.header-logo img {
  height: 40px;
  width: auto;
  object-fit: contain;
}

.header-nav-desktop {
  display: flex;
}

.header-nav {
  display: flex;
  gap: 2rem;
  list-style: none;
  flex-wrap: wrap;
  align-items: center;
  margin: 0;
  padding: 0;
}

.header-nav a {
  color: var(--text-primary);
  text-decoration: none;
  font-size: 1rem;
  transition: color 0.3s ease;
  padding: 0.5rem 0;
  position: relative;
}

.header-nav a:hover {
  color: var(--accent-blue-light);
}

.header-nav a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--accent-blue-light);
  transition: width 0.3s ease;
}

.header-nav a:hover::after {
  width: 100%;
}

.mobile-menu-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 0.5rem;
  z-index: 1001;
  position: relative;
}

.mobile-menu-dropdown {
  display: none;
}

/* Main Content */
main {
  flex: 1;
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
  width: 100%;
}

/* Banner Styles */
.banner {
  width: 100%;
  height: auto;
  object-fit: cover;
  display: block;
  margin: 2rem 0;
  border-radius: 8px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
}

.banner-full {
  width: 100%;
  margin: 0 0 2rem 0;
}

.banner-side {
  width: 100%;
  max-width: 350px;
  min-width: 250px;
  margin: 1rem 0;
  flex-shrink: 0;
}

.banner-container {
  display: flex;
  gap: 1.5rem;
  align-items: flex-start;
  margin: 2rem 0;
}

.banner-container .content {
  flex: 1;
  min-width: 0;
}

/* Hero Banner with H1 */
.hero-banner {
  position: relative;
  width: 100vw;
  margin-left: calc(-50vw + 50%);
  margin-right: calc(-50vw + 50%);
  margin-bottom: 2rem;
  border-radius: 0;
  overflow: hidden;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
}

.hero-banner img {
  width: 100%;
  height: auto;
  display: block;
  min-height: 600px;
  max-height: 650px;
  object-fit: cover;
}

.hero-banner h1 {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  color: var(--text-primary);
  text-align: center;
  font-size: 2.5rem;
  font-weight: 700;
  text-shadow: 2px 2px 8px rgba(0, 0, 0, 0.8);
  padding: 1rem;
  width: 90%;
  max-width: 900px;
  z-index: 10;
  margin: 0;
}

/* Sections */
section {
  margin-bottom: 3rem;
  background-color: var(--dark-blue-light);
  padding: 2rem;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

section h1 {
  font-size: 2.5rem;
  margin-bottom: 1.5rem;
  color: var(--text-primary);
  font-weight: 700;
}

section h2 {
  font-size: 2rem;
  margin-bottom: 1rem;
  margin-top: 2rem;
  color: var(--accent-blue-light);
  font-weight: 600;
}

section p {
  margin-bottom: 1rem;
  color: var(--text-secondary);
  font-size: 1.1rem;
}

section ul,
section ol {
  margin: 1rem 0;
  padding-left: 2rem;
  color: var(--text-secondary);
}

section li {
  margin-bottom: 0.5rem;
  font-size: 1.1rem;
}

/* Table Styles */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 2rem 0;
  background-color: var(--dark-blue-light);
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

table thead {
  background-color: var(--dark-blue-lighter);
}

table th {
  padding: 1rem;
  text-align: left;
  color: var(--text-primary);
  font-weight: 600;
  border-bottom: 2px solid var(--border-color);
}

table td {
  padding: 1rem;
  color: var(--text-secondary);
  border-bottom: 1px solid var(--border-color);
}

table tbody tr:hover {
  background-color: var(--hover-bg);
}

table tbody tr:last-child td {
  border-bottom: none;
}

/* Definition List (FAQ) */
dl {
  margin: 2rem 0;
}

dt {
  font-weight: 600;
  color: var(--accent-blue-light);
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
  font-size: 1.2rem;
  cursor: pointer;
  user-select: none;
  padding: 1rem;
  background-color: var(--dark-blue-light);
  border-radius: 8px;
  transition: background-color 0.3s ease, color 0.3s ease;
  position: relative;
  padding-right: 3rem;
}

dt:hover {
  background-color: var(--hover-bg);
  color: var(--accent-blue-light);
}

dt::after {
  content: '+';
  position: absolute;
  right: 1rem;
  top: 50%;
  transform: translateY(-50%);
  font-size: 1.5rem;
  font-weight: 300;
  transition: transform 0.3s ease;
}

dt.active::after {
  transform: translateY(-50%) rotate(45deg);
}

dt.active {
  background-color: var(--dark-blue-lighter);
}

dd {
  margin: 0 0 0 1.5rem;
  color: var(--text-secondary);
  font-size: 1.1rem;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, margin 0.3s ease, padding 0.3s ease;
  padding: 0 1rem;
}

dd.active {
  max-height: 500px;
  margin: 0 0 1rem 1.5rem;
  padding: 1rem;
  background-color: var(--dark-blue-light);
  border-radius: 8px;
}

/* Footer Styles */
footer {
  background-color: var(--dark-blue-light);
  border-top: 1px solid var(--border-color);
  padding: 2rem 0;
  margin-top: auto;
}

.footer-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: center;
  gap: 2rem;
  flex-wrap: wrap;
}

.footer-logo a{
  display: flex;
  align-items: center;
  flex-shrink: 0;
  background-color: var(--accent-blue-light);
  padding: 0.5rem 1rem;
  border-radius: 8px;
  transition: background-color 0.3s ease;
}

.footer-logo a:hover {
  background-color: var(--accent-blue);
}

.footer-logo img {
  height: 40px;
  width: auto;
  object-fit: contain;
}

.footer-nav {
  display: flex;
  gap: 2rem;
  list-style: none;
  flex-wrap: wrap;
  align-items: center;
}

.footer-nav a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.95rem;
  transition: color 0.3s ease;
}

.footer-nav a:hover {
  color: var(--accent-blue-light);
}

.footer-copyright {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin: 0;
}

/* 404 Page */
.error-404 {
  text-align: center;
  padding: 4rem 2rem;
  min-height: 60vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}

.error-404 h1 {
  font-size: 6rem;
  color: var(--accent-blue);
  margin-bottom: 1rem;
  font-weight: 700;
}

.error-404 p {
  font-size: 1.5rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
}

.error-404 a {
  color: var(--accent-blue-light);
  text-decoration: underline;
  transition: color 0.3s ease;
}

.error-404 a:hover {
  color: var(--accent-blue);
}

/* Scroll to Top Button */
.scroll-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 50px;
  height: 50px;
  background-color: var(--accent-blue);
  color: var(--text-primary);
  border: none;
  border-radius: 50%;
  cursor: pointer;
  display: none;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  z-index: 999;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
  transition: background-color 0.3s ease, transform 0.3s ease, opacity 0.3s ease;
  opacity: 0.8;
}

.scroll-to-top:hover {
  background-color: var(--accent-blue-light);
  transform: translateY(-3px);
  opacity: 1;
}

.scroll-to-top.active {
  display: flex;
}

.scroll-to-top::before {
  content: '↑';
  font-size: 1.5rem;
  line-height: 1;
}

/* Responsive Design */

/* PC - min 1025px */
@media (min-width: 1025px) {
  .header-container,
  .footer-container {
    padding: 0 2rem;
  }
  
  main {
    padding: 3rem 2rem;
  }
  
  .banner-container {
    flex-direction: row;
    gap: 1.5rem;
  }
  
  .banner-side {
    max-width: 350px;
    min-width: 250px;
  }
}

/* Laptop - max 1024px */
@media (max-width: 1024px) {
  .header-container,
  .footer-container {
    padding: 0 1.5rem;
  }
  
  main {
    padding: 2rem 1.5rem;
  }
  
  .hero-banner img {
    min-height: 360px;
    max-height: 400px;
  }
  
  .hero-banner h1 {
    font-size: 2rem;
    top: 50%;
    transform: translate(-50%, -50%);
  }
  
  section h1 {
    font-size: 2rem;
  }
  
  section h2 {
    font-size: 1.75rem;
  }
  
  .banner-container {
    flex-direction: column;
  }
  
  .banner-side {
    max-width: 100%;
  }
}

/* Tablet - max 768px */
@media (max-width: 768px) {
  .header-container {
    flex-wrap: wrap;
    position: relative;
  }
  
  .header-nav-desktop {
    display: none;
  }
  
  .mobile-menu-toggle {
    display: block;
  }
  
  .mobile-menu-dropdown {
    display: block;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: var(--dark-blue-light);
    border-bottom: 1px solid var(--border-color);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
    z-index: 999;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
    margin-top: 1rem;
  }

  .mobile-menu-dropdown.active {
    max-height: 500px;
  }

  .mobile-menu-dropdown .header-nav {
    flex-direction: column;
    gap: 0;
    padding: 1rem 0;
    width: 100%;
  }

  .mobile-menu-dropdown .header-nav li {
    width: 100%;
  }

  .mobile-menu-dropdown .header-nav a {
    display: block;
    width: 100%;
    padding: 1rem 1.5rem;
    border-bottom: 1px solid var(--border-color);
    text-align: left;
  }

  .mobile-menu-dropdown .header-nav a::after {
    display: none;
  }

  .mobile-menu-dropdown .header-nav a:hover {
    background-color: var(--hover-bg);
    color: var(--accent-blue-light);
  }
  
  .hero-banner img {
    min-height: 300px;
    max-height: 350px;
  }
  
  .hero-banner h1 {
    font-size: 1.75rem;
    padding: 0.75rem;
    top: 50%;
    transform: translate(-50%, -50%);
  }
  
  section h1 {
    font-size: 1.75rem;
  }
  
  section h2 {
    font-size: 1.5rem;
  }
  
  section p,
  section li {
    font-size: 1rem;
  }
  
  table {
    font-size: 0.9rem;
  }
  
  table th,
  table td {
    padding: 0.75rem;
  }
  
  .footer-container {
    flex-direction: column;
    text-align: center;
  }
  
  .footer-nav {
    justify-content: center;
  }
  
  .error-404 h1 {
    font-size: 4rem;
  }
  
  .error-404 p {
    font-size: 1.25rem;
  }
  
  .scroll-to-top {
    bottom: 1.5rem;
    right: 1.5rem;
    width: 45px;
    height: 45px;
    font-size: 1.3rem;
  }
}

/* Mobile L - max 425px */
@media (max-width: 425px) {
  .header-container {
    padding: 0 1rem;
  }
  
  main {
    padding: 1.5rem 1rem;
  }
  
  .header-logo img,
  .footer-logo img {
    height: 32px;
  }
  
  .hero-banner img {
    min-height: 280px;
    max-height: 340px;
  }
  
  .hero-banner h1 {
    font-size: 1.5rem;
    padding: 0.5rem;
    top: 50%;
    transform: translate(-50%, -50%);
  }

  section{
    padding: 1.5rem 1rem;
  }
  
  section h1 {
    font-size: 1.5rem;
  }
  
  section h2 {
    font-size: 1.25rem;
  }
  
  section p,
  section li {
    font-size: 0.95rem;
  }
  
  table {
    font-size: 0.85rem;
    display: block;
    overflow-x: auto;
  }
  
  table th,
  table td {
    padding: 0.5rem;
    white-space: nowrap;
  }
  
  dt {
    font-size: 1.1rem;
  }
  
  dd {
    font-size: 1rem;
  }
  
  .footer-container {
    padding: 0 1rem;
  }
  
  .footer-nav {
    flex-direction: column;
    gap: 1rem;
  }
  
  .error-404 {
    padding: 2rem 1rem;
  }
  
  .error-404 h1 {
    font-size: 3rem;
  }
  
  .error-404 p {
    font-size: 1.1rem;
  }
  
  .scroll-to-top {
    bottom: 1.5rem;
    right: 1.5rem;
    width: 45px;
    height: 45px;
    font-size: 1.3rem;
  }
}

/* Mobile M - max 375px */
@media (max-width: 375px) {
  .header-container {
    padding: 0 0.75rem;
  }
  
  main {
    padding: 1rem 0.75rem;
  }
  
  .header-logo img,
  .footer-logo img {
    height: 28px;
  }
  
  .hero-banner img {
    min-height: 240px;
    max-height: 290px;
  }
  
  .hero-banner h1 {
    font-size: 1.25rem;
    top: 50%;
    transform: translate(-50%, -50%);
    padding: 0.5rem;
  }
  
  section h1 {
    font-size: 1.25rem;
  }
  
  section h2 {
    font-size: 1.1rem;
  }
  
  section p,
  section li {
    font-size: 0.9rem;
  }
  
  table {
    font-size: 0.8rem;
  }
  
  table th,
  table td {
    padding: 0.4rem;
  }
  
  dt {
    font-size: 1rem;
  }
  
  dd {
    font-size: 0.95rem;
  }
  
  .footer-container {
    padding: 0 0.75rem;
  }
  
  .error-404 h1 {
    font-size: 2.5rem;
  }
  
  .error-404 p {
    font-size: 1rem;
  }
  
  .scroll-to-top {
    bottom: 1rem;
    right: 1rem;
    width: 42px;
    height: 42px;
    font-size: 1.2rem;
  }
}

/* Mobile S - max 320px */
@media (max-width: 320px) {
  .header-container {
    padding: 0 0.5rem;
  }
  
  main {
    padding: 1rem 0.5rem;
  }
  
  .header-logo img,
  .footer-logo img {
    height: 24px;
  }
  
  .hero-banner img {
    min-height: 200px;
    max-height: 250px;
  }
  
  .hero-banner h1 {
    font-size: 1.1rem;
    top: 50%;
    transform: translate(-50%, -50%);
    padding: 0.4rem;
  }
  
  section h1 {
    font-size: 1.1rem;
  }
  
  section h2 {
    font-size: 1rem;
  }
  
  section p,
  section li {
    font-size: 0.85rem;
  }
  
  table {
    font-size: 0.75rem;
  }
  
  table th,
  table td {
    padding: 0.35rem;
  }
  
  dt {
    font-size: 0.95rem;
  }
  
  dd {
    font-size: 0.9rem;
  }
  
  .footer-container {
    padding: 0 0.5rem;
  }
  
  .footer-nav {
    gap: 0.75rem;
  }
  
  .error-404 h1 {
    font-size: 2rem;
  }
  
  .error-404 p {
    font-size: 0.95rem;
  }
  
  .scroll-to-top {
    bottom: 1rem;
    right: 1rem;
    width: 40px;
    height: 40px;
    font-size: 1.2rem;
  }
}