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

:root {
  --primary-color: #3498db;
  --secondary-color: #061017;
  --secondary-color-op: rgba(17, 17, 18, 0.581);
  --text-color: #ffffff;
  --text-color-dark: #2c3e50;
  --background-color-light: #f4f4f4;
}

body {
  font-family: Arial, sans-serif;
  background-color: var(--background-color-light);
  font-size: 16px;
}

.main {
  margin: 0 auto;
  display: flex;
  justify-content: center;
  align-content: flex-start;
  flex-wrap: wrap;
  margin-bottom: 50px;
  overflow: auto;
  padding: 40px;
  width: 100%;
  max-width: 1920px;
  min-height: calc(100vh - 90px);
}

.link_box {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  gap: 5px;
  margin-bottom: 20px;
}

.link_item {
  padding: 10px 15px;
  background-color: var(--primary-color);
  color: var(--text-color);
  border-radius: 15px 5px 5px 5px;
  box-shadow: none;
  cursor: pointer;
  list-style: none;
  transition:
    background-color 0.3s,
    box-shadow 0.3s;
}

.link_item.active {
  background-color: var(--secondary-color);
  box-shadow: 5px 5px 2px var(--secondary-color-op);
}

.link_item:hover {
  background-color: var(--secondary-color);
  box-shadow: 5px 5px 2px var(--secondary-color-op);
}

.content_box {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  max-height: 100%;
  width: 100%;
}

.content_item {
  display: none;
  height: 100%;
  width: 100%;
  background-color: var(--text-color);
  border: 2px solid var(--primary-color);
  border-radius: 5px;
  padding: 20px;
  overflow: auto;
}

.content_item.active {
  display: block;
}

.accordion {
  width: 100%;
  margin: 0 auto;
  background-color: var(--text-color);
  border-radius: 6px;
  overflow: hidden;
  border: 1px solid var(--background-color-light);
}

.accordion-header {
  padding: 15px;
  cursor: pointer;
  background-color: var(--primary-color);
  color: var(--text-color);
  font-weight: bold;
  border-bottom: 1px solid var(--background-color-light);
  user-select: none;
}

.accordion-content {
  max-height: 0;
  overflow: auto;
  transition: max-height 0.3s ease;
  padding: 0 15px;
  background-color: var(--background-color-light);
}

.accordion-content p {
  margin: 15px 0;
}

.accordion-item {
  margin: 10px;
}

.accordion-item.active .accordion-content {
  max-height: 750px;
}

.link {
  color: var(--primary-color);
  text-decoration: none;
  transition: all 0.3s;
}

.link:hover {
  text-decoration: underline;
  color: var(--secondary-color);
}

h1,
h2,
h3,
h4 {
  color: var(--text-color-dark);
  border-bottom: 1px solid var(--text-color-dark);
  padding: 10px;
  margin: 2px;
}

.h1 {
  font-size: 32px;
}

h1 {
  border-bottom: 3px solid var(--text-color-dark);
  padding-bottom: 10px;
}

section {
  margin-bottom: 40px;
}

pre {
  background: var(--secondary-color);
  padding: 15px;
  overflow-x: auto;
  border-radius: 6px;
}

code {
  font-family: Consolas, monospace;
  background: var(--secondary-color-op);
  color: var(--text-color);
  border-radius: 6px;
  padding: 0 2px;
  margin: 3px;
}

ul {
  margin: 20px;
}

li {
  margin: 5px;
}

.note {
  background: var(--background-color-light);
  padding: 15px;
  border-left: 5px solid var(--primary-color);
  margin: 20px 0;
}

@media (max-width: 1024px) {
  .main {
    padding: 30px;
  }

  .link_item {
    padding: 8px 12px;
  }

  h1 {
    font-size: 1.8rem;
  }
}

@media (max-width: 768px) {
  .main {
    padding: 20px;
    min-height: calc(100vh - 70px);
  }

  .link_box {
    gap: 8px;
  }

  .content_item {
    padding: 15px;
  }

  .accordion-item.active .accordion-content {
    max-height: 1000px;
  }

  pre {
    padding: 10px;
  }
}

@media (max-width: 480px) {
  body {
    font-size: 14px;
  }

  .main {
    padding: 10px;
    margin-bottom: 20px;
  }

  .link_box {
    justify-content: flex-start;
    overflow-x: auto;
    white-space: nowrap;
    flex-wrap: nowrap;
    padding-bottom: 10px;
  }

  .link_item {
    flex: 0 0 auto;
    padding: 8px 10px;
    font-size: 13px;
  }

  h1 {
    font-size: 1.5rem;
    padding: 5px;
  }

  h2 {
    font-size: 1.3rem;
  }

  .accordion-header {
    padding: 12px;
    font-size: 14px;
  }

  code {
    font-size: 12px;
  }

  .note {
    padding: 10px;
    margin: 15px 0;
  }
}