/* css variables*/
:root {
  --primary-color: #2c3e50;
  --primary-color-light: #34495e;
  --accent-color: #3498db;
  /* Professional Blue */
  --accent-color-light: #5dade2;
  --accent-color-dark: #2980b9;
  --white-color: #ffffff;
  --light-gray-color: #ecf0f1;
  --medium-gray-color: #bdc3c7;
  --dark-gray-color: #7f8c8d;
  --bg-color: #f8f9fa;
  /* Clean light gray background */
  --code-bg-color: #f4f4f4;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.05), 0 4px 6px -2px rgba(0, 0, 0, 0.025);
  --border-color: #e9ecef;
}

/* normalized */
html {
  scroll-behavior: smooth;
}

body {
  padding: 0;
  margin: 0;
  font-family: 'Poppins', sans-serif;
  background-color: var(--bg-color);
  color: var(--primary-color);
  line-height: 1.7;
  letter-spacing: 0.01em;
  min-height: 100vh;
}

p {
  font-weight: 400;
  color: var(--primary-color-light);
  margin-bottom: 1.5rem;
  font-size: 1rem;
}

a {
  text-decoration: none;
  color: var(--accent-color);
  transition: color 0.2s ease;
  font-weight: 500;
}

a:hover {
  color: var(--accent-color-dark);
}

hr {
  padding: 1rem 0;
  border: 0;
  border-bottom: 1px solid var(--border-color);
}

* {
  box-sizing: border-box;
}

/* global components */

/* typography */
h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: 'Montserrat', sans-serif;
  color: var(--primary-color);
  font-weight: 700;
  margin-top: 0;
  line-height: 1.3;
  letter-spacing: -0.01em;
}

.section__title {
  color: var(--primary-color);
  font-size: 2rem;
  margin-bottom: 1.5rem;
  position: relative;
  display: inline-block;
  padding-bottom: 0.5rem;
}

.section__title::after {
  content: '';
  display: block;
  width: 40px;
  height: 4px;
  background: var(--accent-color);
  margin-top: 8px;
  border-radius: 2px;
}

/* Scroll Reveal Animation */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: all 0.6s ease-out;
}

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

/* Clean Card Style */
.card {
  background: var(--white-color);
  border-radius: 8px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-color);
  padding: 2.5rem;
  margin-bottom: 2rem;
  transition: box-shadow 0.3s ease;
}

.card:hover {
  box-shadow: var(--shadow-md);
}

/* Publication Card Style */
.pub-card {
  background: var(--white-color);
  border: 1px solid var(--border-color);
  border-left: 4px solid var(--accent-color);
  padding: 1.5rem;
  margin-bottom: 1rem;
  border-radius: 4px;
  transition: all 0.2s ease;
}

.pub-card:hover {
  box-shadow: var(--shadow-sm);
  transform: translateX(2px);
  border-color: var(--accent-color-light);
}

.pub-title {
  font-weight: 600;
  color: var(--primary-color);
  margin-bottom: 0.5rem;
  display: block;
  font-family: 'Montserrat', sans-serif;
  font-size: 1.1rem;
}

.pub-authors {
  font-size: 0.9rem;
  color: var(--dark-gray-color);
  margin-bottom: 0.5rem;
}

.pub-journal {
  font-style: italic;
  font-size: 0.9rem;
  color: var(--primary-color-light);
}

/* Hero Section */
.hero {
  text-align: center;
  padding: 5rem 2rem;
  background: var(--white-color);
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 3rem;
}

.hero__title {
  font-size: 3rem;
  margin-bottom: 1rem;
  color: var(--primary-color);
  font-family: 'Montserrat', sans-serif;
}

.hero p {
  font-size: 1.2rem;
  max-width: 700px;
  margin: 0 auto;
  color: var(--dark-gray-color);
  font-weight: 300;
}

/* tabs */
.tab__container {
  position: relative;
  background: var(--white-color);
  border-radius: 6px;
  border: 1px solid var(--border-color);
  overflow: hidden;
  margin-bottom: 2rem;
}

.tab__container>ul {
  position: absolute;
  list-style: none;
  margin: 0;
  right: 1rem;
  top: 0.5rem;
  padding-left: 0;
  z-index: 10;
}

.tab__container .code {
  white-space: normal;
  padding: 2rem;
  border: none;
  background: transparent;
}

.tab {
  display: inline-block;
  padding: 0.3rem 0.8rem;
  font-weight: 500;
  cursor: pointer;
  color: var(--medium-gray-color);
  font-size: 0.85rem;
  transition: color 0.2s ease;
}

.tab.active {
  color: var(--primary-color);
  border-bottom: 2px solid var(--accent-color);
}

.tab__pane {
  display: none;
}

.tab__pane.active {
  display: block;
}

/* code */
.code {
  border-radius: 4px;
  font-family: 'Fira Code', 'Consolas', monospace;
  background: var(--code-bg-color);
  border: 1px solid var(--border-color);
  color: var(--primary-color);
  font-size: 0.9rem;
}

.code--block {
  white-space: pre-wrap;
  padding: 1.5rem;
  background: var(--code-bg-color);
  border-radius: 6px;
}

.code--inline {
  padding: 2px 6px;
  font-size: 90%;
  background: var(--code-bg-color);
  border-radius: 4px;
  color: var(--primary-color);
  border: 1px solid var(--border-color);
}

/* buttons */
.button--primary {
  padding: 12px 28px;
  background-color: var(--accent-color);
  color: white;
  display: inline-block;
  text-decoration: none;
  border: none;
  border-radius: 4px;
  font-weight: 600;
  font-size: 1rem;
  transition: all 0.2s ease;
  font-family: 'Montserrat', sans-serif;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.button--primary:hover {
  background-color: var(--accent-color-dark);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
  color: white;
}

.button--secondary {
  padding: 10px 24px;
  border: 1px solid var(--primary-color);
  border-radius: 4px;
  color: var(--primary-color);
  font-weight: 600;
  transition: all 0.2s ease;
  background: transparent;
}

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

/* links */
.link {
  text-decoration: none;
  font-weight: 500;
}

.link--dark {
  color: var(--primary-color);
}

.link--dark:hover {
  color: var(--accent-color);
}

.link--light {
  color: rgba(255, 255, 255, 0.9);
}

.link--light:hover {
  color: white;
}

/* menu */
nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 0;
}

.menu {
  margin: 0;
  padding: 0;
  list-style: none;
  display: flex;
  gap: 20px;
}

.menu__item {
  display: inline-block;
}

.menu__item a {
  color: var(--primary-color);
  font-weight: 500;
  font-size: 0.95rem;
}

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

.toggle {
  display: none;
}

/* table */
table {
  border-collapse: collapse;
  width: 100%;
  margin-bottom: 2rem;
  background: var(--white-color);
  border-radius: 6px;
  overflow: hidden;
  border: 1px solid var(--border-color);
}

table td,
table th {
  padding: 1rem;
  text-align: left;
  border-bottom: 1px solid var(--border-color);
}

table th {
  background-color: #f8f9fa;
  font-weight: 600;
  color: var(--primary-color);
}

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

table tr:hover {
  background-color: #f8f9fa;
}

/* responsive */
@media screen and (max-width: 768px) {
  nav {
    flex-wrap: wrap;
  }

  .menu {
    display: none;
    width: 100%;
    flex-direction: column;
    text-align: center;
    padding-top: 1rem;
  }

  .menu.responsive {
    display: flex;
  }

  .toggle {
    display: block;
    cursor: pointer;
  }

  .toggle span {
    display: block;
    width: 25px;
    height: 3px;
    background: var(--primary-color);
    margin: 5px 0;
    transition: 0.3s;
  }
}

/* layout */
.wrapper {
  margin: 0 auto;
  width: 90%;
  max-width: 1200px;
}

.footer {
  text-align: center;
  background-color: var(--white-color);
  padding: 3rem 1rem;
  color: var(--primary-color);
  margin-top: auto;
  border-top: 1px solid var(--border-color);
}

.footer p {
  color: var(--dark-gray-color);
  margin: 0;
}

@keyframes fadeUp {
  0% {
    opacity: 0;
    transform: translate3d(0, 20px, 0);
  }

  100% {
    opacity: 1;
    transform: translate3d(0, 0, 0);
  }
}