:root {
  --primary-color: #4361ee;
  --secondary-color: #3a0ca3;
  --accent-color: #7209b7;
  --light-color: #f8f9fa;
  --dark-color: #212529;
  --success-color: #4cc9f0;
  --warning-color: #f8961e;
  --danger-color: #ef233c;
  --border-radius: 8px;
  --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  --transition: all 0.3s ease;
}
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  line-height: 1.6;
  color: var(--dark-color);
  background-color: #f5f7ff;
  overflow-x: hidden;
}
a {
  text-decoration: none;
  color: var(--primary-color);
  transition: var(--transition);
}
a:hover {
  color: var(--secondary-color);
}
.container {
  width: 100%;
  max-width: 1500px;
  margin: 0 auto;
  padding: 10px 20px;
}
section {
  padding: 60px 0;
}
.section-title {
  text-align: center;
  margin-bottom: 40px;
  font-size: 2rem;
  color: var(--secondary-color);
  position: relative;
}
.section-title::after {
  content: "";
  display: block;
  width: 80px;
  height: 4px;
  background: var(--accent-color);
  margin: 10px auto;
  border-radius: 2px;
}
.btn {
  display: inline-block;
  padding: 10px 20px;
  background: var(--primary-color);
  color: white;
  border: none;
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: var(--transition);
  font-weight: 500;
}
.btn:hover {
  background: var(--secondary-color);
  transform: translateY(-2px);
  box-shadow: var(--box-shadow);
}
.btn-outline {
  background: transparent;
  border: 2px solid var(--primary-color);
  color: var(--primary-color);
}
.btn-outline:hover {
  background: var(--primary-color);
  color: white;
}
#add-subject-btn,
#refresh-subjects-btn {
  flex: 1;
}
#refresh-subjects-btn i {
  margin-right: 5px;
}
.back-button-container {
  margin-bottom: 20px;
  display: flex;
  justify-content: center;
}
.back-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background-color: var(--primary-color);
  color: var(--light-color);
  padding: 8px 16px;
  border-radius: var(--border-radius);
  transition: var(--transition);
}
.back-btn:hover {
  background-color: var(--secondary-color);
  transform: translateY(-2px);
  box-shadow: var(--box-shadow);
  color: var(--light-color);
}
.navbar {
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  transition: var(--transition);
}
.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 15px 20px;
  position: relative;
  margin: 0px;
}
.nav-logo {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
}
.nav-logo a {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary-color);
  text-decoration: none;
}
.nav-logo img {
  max-height: 40px;
  width: auto;
  display: block;
}
.nav-icons {
  display: flex;
  align-items: center;
  gap: 15px;
}
.nav-icons i {
  font-size: 1.2rem;
  color: var(--dark-color);
  cursor: pointer;
  transition: var(--transition);
}
.nav-icons i:hover {
  color: var(--primary-color);
}
.hamburger {
  display: flex;
  flex-direction: column;
  cursor: pointer;
  z-index: 1001;
}
.bar {
  width: 25px;
  height: 3px;
  background: var(--dark-color);
  margin: 3px 0;
  transition: var(--transition);
}
.sidebar {
  position: fixed;
  top: 0;
  left: -300px;
  width: 300px;
  height: 100%;
  background: white;
  z-index: 1000;
  transition: var(--transition);
  box-shadow: 2px 0 10px rgba(0, 0, 0, 0.1);
  overflow-y: auto;
}
.sidebar.active {
  left: 0;
}
.sidebar-header {
  display: flex;
  justify-content: left;
  align-items: center;
  padding: 13px;
  border-bottom: 1px solid #eee;
  background: var(--light-color);
  color: var(--dark-color);
}
.sidebar-header h3 {
  margin: 0;
  font-size: 1.2rem;
  display: flex;
  align-items: center;
}
.sidebar-header h3 img {
  max-height: 35px;
  width: auto;
  display: block;
}
.sidebar-close {
  background: none;
  border: none;
  color: var(--dark-color);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 0;
  width: 30px;
  height: 30px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
}
.sidebar-close:hover {
  background: rgba(0, 0, 0, 0.1);
  border-radius: 50%;
}
.sidebar-content {
  padding: 0;
}
.menu-section {
  border-bottom: 1px solid #eee;
}
.menu-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 15px 20px;
  cursor: pointer;
  transition: var(--transition);
  border-bottom: 1px solid #f5f5f5;
}
.menu-item:hover {
  background: #f8f9fa;
}
.menu-item:last-child {
  border-bottom: none;
}
.menu-text {
  font-size: 1rem;
  color: var(--dark-color);
  font-weight: 500;
  text-decoration: none;
  display: block;
  width: 100%;
}
.menu-text:hover {
  color: var(--primary-color);
}
.menu-arrow {
  font-size: 0.8rem;
  color: var(--primary-color);
  transition: var(--transition);
}
.menu-parent.active .menu-arrow {
  transform: rotate(180deg);
}

/* Menu link styling - looks like parent but entire area is clickable */
.menu-link {
  position: relative;
}
.menu-link a {
  display: block;
  width: 100%;
  height: 100%;
  padding: 15px 20px;
  margin: -15px -20px;
  color: var(--dark-color);
  text-decoration: none;
  font-weight: 500;
  transition: var(--transition);
}
.menu-link:hover a {
  color: var(--primary-color);
}
.menu-link:hover {
  background: #f8f9fa;
}
.submenu {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
  background: #f8f9fa;
}
.submenu.active {
  max-height: 1000px;
}
.submenu .menu-item {
  padding-left: 40px;
  font-size: 0.95rem;
}
.submenu .submenu .menu-item {
  padding-left: 60px;
  font-size: 0.9rem;
}
.submenu .submenu .submenu .menu-item {
  padding-left: 80px;
  font-size: 0.85rem;
}
footer {
  background: var(--light-color);
  padding: 3rem 0 1rem;
  border-top: 1px solid var(--dark-color);
}
.footer-logo-row {
  display: flex;
  align-items: center;
  gap: 12px;
}
.footer-logo-row img {
  max-height: 45px;
  transform: scale(1);
  margin-top: 0;
  padding-left: 0;
}
.footer-logo-row h3 {
  margin: 0;
  color: var(--primary-color);
  font-size: 1.5rem;
  padding-top: 15px;
  margin-left: -9px;
  font-weight: bold;
  letter-spacing: 1px;
}
.footer-container {
  max-width: 1500px;
  margin: 0 auto;
  padding: 0 25px;
}
.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
  margin-bottom: 2rem;
}
.footer-content .footer-section:not(:first-child) {
  margin-top: 1.3rem;
}
.footer-section h3 {
  color: var(--primary-color);
  margin-bottom: 1rem;
}
.footer-section ul {
  list-style: none;
}
.footer-section a {
  color: var(--dark-color);
  text-decoration: none;
  transition: color 0.3s ease;
}
.footer-section a:hover {
  color: var(--primary-color);
}
.footer-section p {
  color: var(--dark-color);
}

/* Footer Social Icons */
.social-icons {
  margin-top: 15px;
  display: flex;
  gap: 15px;
}
.social-icons a {
  font-size: 24px;
  color: #333;
  transition: 0.3s;
}
.social-icons a:hover {
  transform: scale(1.2);
}
.social-icons a.instagram:hover {
  color: #e4405f;
}
.social-icons a.facebook:hover {
  color: #1877f2;
}
.social-icons a.linkedin:hover {
  color: #0a66c2;
}

.footer-bottom {
  text-align: center;
  padding-top: 2rem;
  border-top: 1px solid var(--dark-color);
  color: var(--dark-color);
}
.footer-bottom a {
  text-decoration: none;
  color: inherit;
}
.footer-bottom a:hover {
  color: var(--primary-color);
  text-decoration: none;
}
.bd-small {
  font-size: 0.5em;
  vertical-align: super;
  font-weight: bold;
  letter-spacing: 0.5px;
}
@media (max-width: 1400px) {
  .container {
    max-width: 1200px;
    padding: 12px 30px;
  }
  .header-content {
    gap: 30px;
  }
  .logo {
    font-size: 2.2rem;
  }
  .tagline {
    font-size: 1.3rem;
  }
  .welcome-text {
    font-size: 1rem;
  }
  .countdown-container {
    padding: 35px;
  }
  .countdown-title {
    font-size: 1.6rem;
  }
  .ad-main-text {
    font-size: 1.8rem;
  }
  .calculator-container {
    gap: 25px;
    padding: 25px;
  }
  .nav-container {
    padding: 15px 30px;
  }
}
@media (max-width: 1200px) {
  .container {
    max-width: 1000px;
    padding: 12px 25px;
  }
  .header-content {
    gap: 25px;
    min-height: 50vh;
  }
  .logo {
    font-size: 2rem;
  }
  .tagline {
    font-size: 1.2rem;
  }
  .welcome-text {
    font-size: 0.95rem;
    margin-bottom: 25px;
  }
  .typing-text {
    font-size: 1.1rem;
    min-height: 50px;
  }
  .countdown-container {
    padding: 30px;
    max-width: 450px;
  }
  .countdown-title {
    font-size: 1.5rem;
  }
  .countdown-subtitle {
    font-size: 1.1rem;
  }
  .countdown {
    gap: 15px;
  }
  .countdown-item {
    padding: 15px;
    min-width: 80px;
  }
  .countdown-number {
    font-size: 2rem;
  }
  .ad-card {
    min-height: 160px;
  }
  .ad-main-text {
    font-size: 1.6rem;
  }
  .ad-sub-text {
    font-size: 0.9rem;
  }
  .ad-image-crop {
    height: 200px;
  }
  .calculator-container {
    grid-template-columns: 1fr;
    gap: 20px;
  }
  .calculator-form {
    grid-template-columns: 1fr 1fr;
  }
  .footer-content {
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
  }
  .nav-container {
    padding: 15px 25px;
  }
}
@media (max-width: 768px) {
  .container {
    padding: 15px 20px;
  }
  section {
    padding: 40px 0;
  }
  .section-title {
    font-size: 1.6rem;
    margin-bottom: 30px;
  }
  .nav-container {
    padding: 15px 20px;
  }
  .nav-logo a {
    font-size: 1.3rem;
  }
  .nav-icons i {
    font-size: 1rem;
  }
  header {
    margin-top: 60px;
    padding: 20px 0;
  }
  .header-content {
    grid-template-columns: 1fr;
    gap: 30px;
    min-height: auto;
    text-align: center;
  }
  .hero-left {
    text-align: center;
    padding-left: 0;
  }
  .hero-right {
    order: +1;
  }
  .logo {
    font-size: 1.8rem;
  }
  .tagline {
    font-size: 1.1rem;
    margin-bottom: 20px;
  }
  .welcome-text {
    font-size: 0.9rem;
    margin-bottom: 20px;
  }
  .typing-text {
    font-size: 1rem;
    min-height: 40px;
    margin-bottom: 20px;
  }
  .batch-dropdown {
    margin-bottom: 15px;
  }
  .batch-select {
    max-width: 250px;
    padding: 10px 12px;
    font-size: 0.9rem;
  }
  .countdown-container {
    padding: 25px;
    max-width: 100%;
  }
  .countdown-title {
    font-size: 1.3rem;
    margin-bottom: 15px;
  }
  .countdown-subtitle {
    font-size: 1rem;
    margin-bottom: 20px;
  }
  .countdown {
    gap: 10px;
  }
  .countdown-item {
    padding: 12px 8px;
    min-width: 60px;
  }
  .countdown-number {
    font-size: 1.5rem;
  }
  .countdown-label {
    font-size: 0.7rem;
  }
  .ad-card {
    flex-direction: row-reverse;
    min-height: auto;
    margin: 30px auto 0 auto;
  }
  .ad-card-left {
    padding: 20px;
    text-align: left;
  }
  .ad-main-text {
    font-size: 1.4rem;
    margin-bottom: 5px;
  }
  .ad-sub-text {
    font-size: 0.85rem;
  }
  .ad-card-right {
    order: -1;
  }
  .ad-image-crop {
    height: 150px;
    border-radius: var(--border-radius) var(--border-radius) 0 0;
  }
  .calculator-container {
    padding: 20px;
  }
  .calculator-form {
    grid-template-columns: 1fr;
    gap: 15px;
  }
  .form-group {
    margin-bottom: 12px;
  }
  .form-group input {
    padding: 8px 10px;
    font-size: 0.9rem;
  }
  .calculator-result {
    padding: 20px;
  }
  .result-title {
    font-size: 1.1rem;
    margin-bottom: 15px;
  }
  .result-value {
    font-size: 1rem;
  }
  .footer {
    padding: 2rem 0 1rem;
  }
  .footer-container {
    padding: 0 1.5rem;
  }
  .footer-content {
    grid-template-columns: 1fr;
    gap: 1.5rem;
    text-align: left;
  }
  .footer-content .footer-section:not(:first-child) {
    margin-top: 0;
  }
  .footer-logo-row {
    justify-content: left;
  }
  .footer-logo-row h3 {
    font-size: 1.3rem;
  }
  .back-button-container {
    margin-bottom: 18px;
    margin-top: 31px;
  }
  .back-btn {
    padding: 7px 14px;
    font-size: 0.9rem;
    gap: 6px;
  }
}
@media (max-width: 640px) {
  .container {
    padding: 5px 15px;
  }
  section {
    padding: 30px 0;
  }
  .section-title {
    font-size: 1.4rem;
    margin-bottom: 25px;
  }
  .back-button-container {
    margin-bottom: 15px;
    margin-top: 15px;
  }
  .back-btn {
    padding: 6px 12px;
    font-size: 0.85rem;
    gap: 5px;
  }
  .nav-container {
    padding: 10px 20px;
  }
  .nav-logo a {
    font-size: 1.2rem;
  }
  .hamburger .bar {
    width: 22px;
    height: 2px;
  }
  header {
    margin-top: 55px;
    padding: 15px 0;
  }
  .header-content {
    gap: 20px;
  }
  .logo {
    font-size: 1.6rem;
    margin-bottom: 8px;
  }
  .tagline {
    font-size: 1rem;
    margin-bottom: 15px;
  }
  .welcome-text {
    font-size: 0.85rem;
    margin-bottom: 15px;
    line-height: 1.6;
  }
  .typing-text {
    font-size: 0.9rem;
    min-height: 35px;
    margin-bottom: 15px;
  }
  .batch-dropdown label {
    font-size: 0.9rem;
    margin-bottom: 6px;
  }
  .batch-select {
    max-width: 200px;
    padding: 8px 10px;
    font-size: 0.85rem;
  }
  .countdown-container {
    padding: 20px;
  }
  .countdown-title {
    font-size: 1.1rem;
    margin-bottom: 10px;
  }
  .countdown-subtitle {
    font-size: 0.9rem;
    margin-bottom: 15px;
  }
  .countdown {
    gap: 8px;
  }
  .countdown-item {
    padding: 10px 6px;
    min-width: 50px;
  }
  .countdown-number {
    font-size: 1.2rem;
    margin-bottom: 3px;
  }
  .countdown-label {
    font-size: 0.6rem;
  }
  .ad-card {
    margin: 20px auto 0 auto;
  }
  .ad-card-left {
    padding: 15px;
  }
  .ad-main-text {
    font-size: 1.2rem;
    margin-bottom: 4px;
  }
  .ad-sub-text {
    font-size: 0.8rem;
  }
  .ad-image-crop {
    height: 120px;
  }
  .calculator-container {
    padding: 15px;
  }
  .calculator-form {
    gap: 12px;
  }
  .form-group {
    margin-bottom: 10px;
  }
  .form-group label {
    font-size: 0.9rem;
    margin-bottom: 4px;
  }
  .form-group input {
    padding: 7px 8px;
    font-size: 0.85rem;
  }
  .calculator-result {
    padding: 15px;
  }
  .result-title {
    font-size: 1rem;
    margin-bottom: 12px;
  }
  .result-item {
    margin-bottom: 12px;
    padding-bottom: 12px;
  }
  .result-label {
    font-size: 0.9rem;
  }
  .result-value {
    font-size: 0.9rem;
  }
  .btn {
    padding: 8px 16px;
    font-size: 0.9rem;
  }
  .footer {
    padding: 1.5rem 0 1rem;
  }
  .footer-container {
    padding: 0 1rem;
  }
  .footer-content {
    gap: 1rem;
  }
  .footer-logo-row {
    gap: 8px;
  }
  .footer-logo-row img {
    max-height: 35px;
  }
  .footer-logo-row h3 {
    font-size: 1.1rem;
    padding-top: 10px;
  }
  .footer-section h3 {
    font-size: 1rem;
    margin-bottom: 0.8rem;
  }
  .footer-section p {
    font-size: 0.85rem;
  }
  .footer-section ul li {
    margin-bottom: 0.5rem;
  }
  .footer-section a {
    font-size: 0.85rem;
  }
  .footer-bottom {
    padding-top: 1.5rem;
    font-size: 0.8rem;
  }
}
@media (max-width: 640px) {
  .sidebar {
    width: 260px;
  }
  .sidebar-header {
    padding: 7px;
  }
  .sidebar-header h3 {
    font-size: 1rem;
  }
  .sidebar-header h3 img {
    max-height: 28px;
  }
  .menu-item {
    padding: 10px 12px;
  }
  .menu-text {
    font-size: 0.9rem;
  }
  .submenu .menu-item {
    padding-left: 25px;
    font-size: 0.85rem;
  }
  .submenu .submenu .menu-item {
    padding-left: 40px;
    font-size: 0.8rem;
  }
  .submenu .submenu .submenu .menu-item {
    padding-left: 55px;
    font-size: 0.75rem;
  }
}