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

body {
  margin: 0;
  background-color: white;
  color: black;
  font-family: Georgia, serif;
  text-align: center;
  position: relative;
  overflow-x: hidden;
  min-height: 100vh; 
  display: flex;
  flex-direction: column;
}

header {
  background-color: #fff;
  border-bottom: 4px solid black;
  padding: 20px 40px;
}

nav {
  display: flex;
  justify-content: flex-end;
  gap: 24px;
}

nav a {
  text-decoration: none;
  font-family: Helvetica, Arial, sans-serif;
  font-weight: bold;
  color: black;
  padding: 6px 10px;
  border-bottom: 3px solid transparent;
  transition: all 0.3s ease;
}

nav a:hover {
  border-bottom: 3px solid red;
  color: #0033a0;
}


main {
  max-width: 700px;
  margin: 80px auto;
  padding: 0 20px;
  background: white;
  position: relative;
  z-index: 2;
}

h1 {
  font-family: Helvetica, Arial, sans-serif;
  color: #0033a0;
  border-bottom: 6px solid #ffcc00;
  display: inline-block;
  padding-bottom: 8px;
  margin-bottom: 24px;
}

.line-red {
  position: absolute;
  top: 0;
  left: 0;
  width: 10px;
  height: 100vh;
  background: red;
  z-index: -1;
}

.line-blue {
  position: absolute;
  top: 0;
  right: 0;
  width: 15px;
  height: 60%;
  background: #0033a0;
  z-index: -1;
}

.line-yellow {
  position: absolute;
  bottom: 0;
  left: 25%;
  width: 50%;
  height: 10px;
  background: #ffcc00;
  z-index: -1;
}


.big-image {
  width: fit-content;
  margin: 40px auto; 
  position: relative;
  z-index: 2;
}

.big-image img {
  width: 600px;
  height: 400px;        
  object-fit: cover;    
  border: 8px solid black;
  box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

.big-image .arrow,
.thumb-images .arrow {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 40px;
  height: 40px;
  border: 3px solid black;
  border-radius: 50%;
  background-color: white;
  color: black;
  font-size: 20px;
  font-weight: bold;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 2px 2px 0 #000;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 5;
}

.big-image .arrow:hover,
.thumb-images .arrow:hover {
  background-color: #ff0000;
  color: white;
  box-shadow: 0 0 0 #000;
  transform: translateY(-50%) scale(1.1);
}

.big-image .arrow.left,
.thumb-images .arrow.left {
  left: -50px;
}

.big-image .arrow.right,
.thumb-images .arrow.right {
  right: -50px;
}


.thumb-images {
  width: fit-content;
  margin: 20px auto 60px; 
  position: relative;
  z-index: 2;
}

.thumbs {
  display: flex;
  gap: 10px;
  overflow-x: auto;
  padding: 10px 0;
}

.thumbs img {
  width: 120px;
  height: 120px;
  object-fit: cover;
  cursor: pointer;
  border: 4px solid transparent;
  transition: border 0.3s ease;
}

.thumbs img.active {
  border-color: red;
}

#art-info {
    max-width: 600px;
    margin: 40px auto;
    padding: 20px;
    border: 4px solid #0033a0; 
    background-color: #f7f7f7; 
    text-align: left;
    border-radius: 8px;
}

#art-text {
    font-family: Georgia, serif;
    font-size: 1.1em;
    line-height: 1.6;
    color: #333;
    white-space: pre-line; 
}

#btn-container {
    text-align: center;
    margin-top: 20px;
}

.mainpage-btn {
    text-decoration: none;
    font-weight: bold;
}

main {
    max-width: 800px; 
    margin: 40px auto; 
}

footer {
  margin-top: auto; 
  background-color: #ffcc00;
  color: black;
  padding: 20px 0;
  border-top: 4px solid black;
  font-family: Helvetica, Arial, sans-serif;
  width: 100%; 
}