:root {
  --primary-color: #007bff;
  --primary-color-hover: #0056b3;
  --primary-color-active: #003f7f;
  --primary-color-dark-theme: #00d4ff;
  --primary-color-dark-theme-hover: #007bff;
  --secondary-color: #00b7eb;
  --accent-color-1: #ff00ff;

  --text-color: #333;
  --text-color-light: #555;
  --text-color-inverted: #fff;

  --bg-color: #f5f7fa;
  --bg-header: #fff;
  --bg-card: #fff;
  --bg-table-row-hover: rgba(0, 212, 255, 0.05);
  
  --bg-dark-color: #1a1a1a;
  --bg-dark-header: #2c2c2c;
  --bg-dark-table-row-hover: rgba(0, 212, 255, 0.1);

  --shadow-main: rgba(0, 0, 0, 0.1);
  --shadow-dark-theme: rgba(255, 255, 255, 0.1);

  --gradient-bg: linear-gradient(135deg, #f5f7fa 0%, #e0e7ff 100%);
  --gradient-bg-dark: linear-gradient(135deg, #1a1a1a 0%, #2c2c2c 100%);
  --gradient-btn: linear-gradient(45deg, #00b7eb, #ff00ff);
  --gradient-btn-hover: linear-gradient(45deg, #ff00ff, #00b7eb);
  
  --font-main: 'Cairo', sans-serif;
  --radius-sm: 8px;
  --radius-md: 15px;
  --radius-lg: 20px;
  --radius-pill: 50px;
}

body.dark-mode {
  --primary-color: var(--primary-color-dark-theme);
  --primary-color-hover: var(--primary-color-dark-theme-hover);
  --text-color: #ddd;
  --text-color-light: #bbb;
  --bg-color: var(--bg-dark-color);
  --bg-header: var(--bg-dark-header);
  --bg-card: var(--bg-dark-header);
  --bg-table-row-hover: var(--bg-dark-table-row-hover);
  --shadow-main: var(--shadow-dark-theme);
  --gradient-bg: var(--gradient-bg-dark);
}

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

body {
  font-family: var(--font-main);
  background: var(--bg-color);
  color: var(--text-color);
  overflow-x: hidden;
  scroll-behavior: smooth;
}

body.no-scroll {
  overflow: hidden;
}

a {
  text-decoration: none;
}

ul {
  list-style: none;
}

.hidden {
  display: none;
}

.show {
  display: block;
}

.hamburger-menu,
.menu-links {
  display: none;
}

.app-header {
  position: fixed;
  top: 0;
  right: 0;
  left: 0;
  background-color: var(--bg-header);
  z-index: 1000;
  transition: top 0.3s ease;
  box-shadow: 0 2px 10px var(--shadow-main);
  padding: 16px 40px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
}

.logo-container .logo {
  font-size: 32px;
  font-weight: 700;
  color: var(--primary-color);
  transition: color 0.3s;
}

.main-nav .nav-list {
  display: flex;
  gap: 24px;
  align-items: center;
}

.main-nav .nav-link {
  font-size: 16px;
  color: var(--text-color);
  font-weight: 500;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  background: rgba(0, 123, 255, 0.1);
  transition: background 0.3s, color 0.3s;
}

.main-nav .nav-link:hover {
  background: rgba(0, 123, 255, 0.2);
  color: var(--primary-color);
}

.main-nav .nav-link:active {
  background: var(--primary-color-hover);
  color: var(--text-color-inverted);
}

.auth-btn {
  background: var(--primary-color);
  color: var(--text-color-inverted);
  border: none;
  padding: 10px 24px;
  border-radius: var(--radius-sm);
  font-size: 16px;
  font-weight: 500;
  cursor: pointer;
  box-shadow: 0 4px 8px rgba(0, 123, 255, 0.2);
  transition: background 0.3s;
}

.auth-btn:hover {
  background: var(--primary-color-hover);
}

.auth-btn:active {
  background: var(--primary-color-active);
}

.dark-mode-toggle {
  background: #a1c9f0;
  border: 1px solid #73a2d2;
  border-radius: 25px;
  cursor: pointer;
  padding: 0;
  width: 60px;
  height: 30px;
  position: relative;
  overflow: hidden;
  transition: background-color 0.6s ease, border-color 0.6s ease;
  flex-shrink: 0;
  -webkit-tap-highlight-color: transparent;
}

.icons-wrapper {
  width: 100%;
  height: 100%;
  position: relative;
}

.light-icon-wrapper,
.dark-icon-wrapper {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  transition: opacity 0.6s ease;
}

.dark-icon-wrapper {
  opacity: 0;
}

.neptune,
.sun {
  position: absolute;
  top: 50%;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  transition: transform 0.6s ease-in-out;
}

.neptune {
  background: radial-gradient(circle, #5b92e5, #3a7bd5, #005aa7);
  box-shadow: inset -2px -1px 4px rgba(0, 0, 0, 0.3);
  transform: translateY(-50%) translateX(3px);
}

.sun {
  background: radial-gradient(circle, #FFD700, #FFA500);
  box-shadow: 0 0 8px #FFD700, 0 0 15px #FFA500;
  transform: translateY(-50%) translateX(33px);
}

.cloud {
  position: absolute;
  background: radial-gradient(ellipse at center, rgba(255, 255, 255, 0.85) 0%, rgba(255, 255, 255, 0) 70%);
  border-radius: 50%;
  width: 40px;
  height: 20px;
  filter: blur(2.5px);
  opacity: 0.9;
  animation: moveClouds 20s linear infinite;
}

.cloud1 { top: -4px; left: 5px; transform: scale(0.8); animation-delay: -2s; }
.cloud2 { top: 10px; left: 25px; transform: scale(0.9); animation-delay: -10s; }
.dark-cloud1 { top: -2px; left: 10px; transform: scale(0.7); animation-delay: -5s; }
.dark-cloud2 { top: 12px; left: 35px; transform: scale(0.8); animation-delay: -15s; }

@keyframes moveClouds {
  0% { transform: translateX(-80px) scale(var(--scale,1)); }
  100% { transform: translateX(80px) scale(var(--scale,1)); }
}

body.dark-mode .dark-mode-toggle {
  background: #1e293b;
  border-color: #334155;
}
body.dark-mode .light-icon-wrapper { opacity: 0; }
body.dark-mode .dark-icon-wrapper { opacity: 1; }
body.dark-mode .neptune { transform: translateY(-50%) translateX(33px); }
body.dark-mode .sun { transform: translateY(-50%) translateX(3px); }

.username-display {
  font-size: 16px;
  color: var(--text-color-light);
  background: rgba(135, 206, 235, 0.1);
  padding: 8px 16px;
  border-radius: 20px;
  font-weight: 500;
  display: inline-block;
  transition: background 0.3s, color 0.3s;
}

.username-display:hover {
  background: rgba(135, 206, 235, 0.3);
}

.hero-dots {
  position: absolute;
  top: 20px;
  left: 20px;
  display: flex;
  gap: 10px;
  z-index: 100;
}

.dot {
  width: 10px;
  height: 10px;
  background: #ccc;
  border-radius: 50%;
  cursor: pointer;
  transition: background 0.3s;
}

.dot.active,
.dot:hover {
  background: var(--secondary-color);
}

.slider-controls {
  position: absolute;
  top: 50%;
  width: 100%;
  display: flex;
  justify-content: space-between;
  padding: 0 20px;
  z-index: 100;
  transform: translateY(-50%);
}

.slider-btn {
  background: rgba(0, 0, 0, 0.5);
  color: #fff;
  border: none;
  padding: 10px;
  font-size: 1.5rem;
  cursor: pointer;
  border-radius: 50%;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.3s;
}

.slider-btn:hover {
  background: var(--secondary-color);
}

.hero-section {
  padding-top: 120px;
  min-height: 80vh;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
}

.hero-slide {
  display: none;
  width: 100%;
  height: 80vh;
  align-items: center;
  justify-content: flex-end;
  padding: 40px;
  position: relative;
  background-size: cover;
  background-position: center;
  z-index: 2;
}

.hero-slide:nth-child(1) { background-image: url('images/student1.jpeg'); }
.hero-slide:nth-child(2) { background-image: url('images/student2.jpeg'); }

.hero-slide.active {
  display: flex;
}

.hero-slide::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  z-index: 1;
}

.hero-content {
  max-width: 500px;
  padding: 20px;
  position: relative;
  z-index: 2;
  text-align: right;
}

.hero-slide .hero-title {
  font-size: 2.5rem;
  color: var(--text-color-inverted);
  margin-bottom: 15px;
  font-weight: 700;
  text-shadow: 0 2px 6px rgba(0, 0, 0, 0.8);
}

.hero-slide .hero-text {
  font-size: 1.1rem;
  color: #e0f7fa;
  line-height: 1.6;
  text-shadow: 0 1px 4px rgba(0, 0, 0, 0.7);
}

.subjects-grid {
  padding: 60px 20px;
  background: var(--gradient-bg);
  position: relative;
  overflow: hidden;
}

.subjects-grid::before {
  content: '';
  position: absolute;
  width: 200px;
  height: 200px;
  background: rgba(0, 183, 235, 0.2);
  border-radius: 50%;
  top: -50px;
  right: -50px;
  z-index: 0;
}

.section-title {
  font-size: 2.5rem;
  text-align: center;
  margin-bottom: 40px;
  color: #1a2a44;
  text-shadow: 0 2px 4px var(--shadow-main);
  position: relative;
  z-index: 1;
}

.search-bar {
  width: 100%;
  max-width: 600px;
  padding: 12px 20px;
  margin: 20px auto;
  display: block;
  border: 2px solid var(--secondary-color);
  border-radius: 25px;
  font-size: 1.1rem;
  text-align: right;
  background: var(--bg-card);
  box-shadow: 0 4px 12px var(--shadow-main);
  transition: border-color 0.3s, box-shadow 0.3s;
  color: var(--text-color);
}

.search-bar:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 4px 20px rgba(0, 123, 255, 0.3);
}

.cards-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 25px;
  max-width: 1300px;
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

.subject-card {
  background: var(--bg-card);
  border-radius: var(--radius-md);
  min-height: 220px;
  position: relative;
  overflow: hidden;
  box-shadow: 0 5px 15px var(--shadow-main);
  transition: box-shadow 0.3s;
}

.subject-card:hover {
  box-shadow: 0 15px 30px rgba(0, 0, 0, 0.2);
}

.card-content {
  padding: 20px;
  text-align: center;
  color: var(--text-color-inverted);
  height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  background: rgba(0, 0, 0, 0.2);
  transition: background 0.3s;
}

.subject-card:hover .card-content {
  background: rgba(0, 0, 0, 0.4);
}

.card-title {
  font-size: 1.8rem;
  font-weight: 700;
  margin-bottom: 10px;
  text-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
}

.card-desc {
  font-size: 1.1rem;
  color: #f0f0f0;
  margin-bottom: 15px;
}

.card-link {
  color: var(--text-color-inverted);
  font-weight: bold;
  font-size: 1.1rem;
  padding: 8px 20px;
  border: 2px solid var(--text-color-inverted);
  border-radius: 25px;
  transition: background 0.3s, color 0.3s;
}

.card-link:hover {
  background: var(--text-color-inverted);
  color: #1a2a44;
}

.physics-card { background: linear-gradient(135deg, #1e90ff 0%, #00d4ff 100%); }
.calculus-card { background: linear-gradient(135deg, #ff6b6b 0%, #ff8c00 100%); }
.chemistry-card { background: linear-gradient(135deg, #00cc99 0%, #33ffcc 100%); }
.mechanics-card { background: linear-gradient(135deg, #4682b4 0%, #87cefa 100%); }
.english-card { background: linear-gradient(135deg, #8a2be2 0%, #d48cff 100%); }
.algebra-card { background: linear-gradient(135deg, #ff69b4 0%, #ff99cc 100%); }

.equation-section {
  background: linear-gradient(135deg, rgba(0, 183, 235, 0.2), rgba(255, 0, 255, 0.2));
  padding: 40px 20px;
  margin: 60px 0;
  border-radius: var(--radius-lg);
  border: 1px solid rgba(0, 212, 255, 0.5);
  box-shadow: 0 0 50px rgba(0, 183, 235, 0.5);
  position: relative;
  overflow: hidden;
}

.equation-section::before,
.equation-section::after,
.contact-section::before,
.contact-section::after {
  content: '';
  position: absolute;
  background: radial-gradient(circle, rgba(0, 212, 255, 0.3), transparent);
}

.equation-section::before,
.contact-section::before {
  top: -50px;
  left: -50px;
  width: 200px;
  height: 200px;
}

.equation-section::after,
.contact-section::after {
  bottom: -30px;
  right: -30px;
  width: 150px;
  height: 150px;
  background: radial-gradient(circle, rgba(255, 0, 255, 0.2), transparent);
}

.equation-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1200px;
  margin: 0 auto;
  flex-direction: row-reverse;
}

.equation-content-wrapper {
  flex: 1;
  text-align: right;
  padding: 20px;
  max-width: 600px;
}

.equation-title {
  font-size: 1.5rem;
  color: #000;
  text-shadow: 0 0 20px rgba(0, 212, 255, 1), 0 0 30px rgba(0, 212, 255, 0.8);
  margin-bottom: 15px;
  line-height: 1.4;
}

.read-more-btn,
.read-less-btn {
  background: var(--gradient-btn);
  color: var(--text-color-inverted);
  padding: 10px 25px;
  border: none;
  border-radius: var(--radius-pill);
  font-size: 1.1rem;
  font-weight: bold;
  cursor: pointer;
  box-shadow: 0 0 25px rgba(0, 212, 255, 0.8);
  transition: transform 0.3s ease, background 0.3s ease;
}

.read-more-btn:hover,
.read-less-btn:hover {
  background: var(--gradient-btn-hover);
  transform: scale(1.05);
}

.read-more-btn,
.read-less-btn {
  margin-top: 20px;
}

.read-less-btn {
  display: none;
  position: relative;
  z-index: 10;
}

.read-less-btn:not(.hidden) {
  display: inline-block;
}

.equation-image-wrapper {
  flex: 1;
  max-width: 450px;
  min-height: 350px;
  display: flex;
  justify-content: center;
  align-items: center;
}

.equation-image {
  width: 100%;
  max-height: 350px;
  object-fit: cover;
  background: #fff;
  padding: 10px;
  border-radius: var(--radius-md);
  box-shadow: 0 3px 10px rgba(0, 0, 0, 0.15);
}

.equation-content {
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  transition: max-height 0.5s ease, opacity 0.5s ease, padding 0.1s ease;
  padding: 0 20px;
}

.equation-content.visible {
  max-height: 3000px;
  opacity: 1;
  padding: 20px;
}

.equation-text {
  font-size: 1.2rem;
  color: var(--text-color);
  margin-bottom: 30px;
  line-height: 1.8;
}

.equation-text h4 {
  font-size: 1.5rem;
  color: var(--secondary-color);
  margin: 20px 0 10px;
  padding-right: 30px;
  position: relative;
}

.equation-text h4::before {
  content: '📘';
  position: absolute;
  right: 0;
  font-size: 1.2rem;
}

.equation-text ul {
  padding-right: 20px;
  margin-bottom: 20px;
}

.equation-text ul li {
  font-size: 1.1rem;
  margin-bottom: 10px;
  padding-right: 20px;
  position: relative;
}

.equation-text ul li::before {
  content: '✔';
  position: absolute;
  right: 0;
  color: var(--secondary-color);
  font-size: 1rem;
}

.equation-text p {
  font-size: 1.1rem;
  margin-bottom: 15px;
  color: #333;
}

.exam-schedule {
  margin-top: 40px;
}

.schedule-title {
  font-size: 1.8rem;
  color: var(--secondary-color);
  margin-bottom: 20px;
  text-align: center;
  position: relative;
  padding-bottom: 10px;
}

.schedule-title::after {
  content: '';
  position: absolute;
  width: 50px;
  height: 3px;
  background: var(--secondary-color);
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
}

.futuristic-table {
  width: 100%;
  max-width: 800px;
  margin: 0 auto;
  border-collapse: separate;
  border-spacing: 0;
  background: var(--bg-card);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: 0 8px 20px var(--shadow-main);
}

.futuristic-table th,
.futuristic-table td {
  padding: 20px;
  text-align: center;
  color: var(--text-color);
  font-size: 1.1rem;
  border: 1px solid rgba(0, 212, 255, 0.3);
}

.futuristic-table th {
  background: linear-gradient(45deg, var(--secondary-color), #1a2a44);
  color: var(--text-color-inverted);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.futuristic-table tbody tr:hover {
  background: var(--bg-table-row-hover);
}

.contact-section {
  padding: 60px 20px;
  text-align: center;
  max-width: 900px;
  margin: 120px auto;
  border-radius: var(--radius-lg);
  border: 1px solid rgba(0, 212, 255, 0.5);
  box-shadow: 0 0 50px rgba(0, 183, 235, 0.5);
  position: relative;
  overflow: hidden;
}

.contact-cta {
  background: var(--gradient-btn);
  color: var(--text-color-inverted);
  padding: 15px 40px;
  border-radius: var(--radius-pill);
  font-weight: bold;
  font-size: 1.2rem;
  display: inline-flex;
  align-items: center;
  gap: 12px;
  border: 2px solid var(--primary-color-dark-theme);
  box-shadow: 0 0 25px rgba(0, 212, 255, 0.8);
  transition: background 0.3s;
}

.contact-cta:hover {
  background: var(--gradient-btn-hover);
}

.contact-cta .whatsapp-icon {
  width: 28px;
  height: 28px;
}

.app-footer {
  background: linear-gradient(135deg, #1a2a44, var(--secondary-color));
  padding: 15px 20px;
  text-align: center;
  color: var(--text-color-inverted);
  font-size: 0.9rem;
  font-weight: 500;
  border-top: 1px solid rgba(0, 212, 255, 0.5);
  box-shadow: 0 -5px 15px rgba(0, 183, 235, 0.3);
  position: relative;
  overflow: hidden;
}

.app-footer p {
  text-shadow: 0 0 5px rgba(0, 212, 255, 0.5);
}

.search-results {
  max-width: 600px;
  margin: 0 auto 40px;
  padding: 10px;
  background: var(--bg-card);
  border-radius: var(--radius-md);
  box-shadow: 0 5px 20px var(--shadow-main);
  max-height: 400px;
  overflow-y: auto;
  position: relative;
  z-index: 1000;
}

.search-result-item {
  padding: 15px;
  border-bottom: 1px solid #eee;
  transition: background 0.3s;
}

.search-result-item:last-child {
  border-bottom: none;
}

.search-result-item:hover {
  background: #f8f9fa;
}

.search-link {
  display: block;
  color: var(--text-color);
}

.search-result-item h3 {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 5px;
  color: var(--primary-color);
  transition: color 0.3s;
}

.search-result-item:hover h3 {
  color: var(--primary-color-hover);
}

.search-result-item p {
  font-size: 0.95rem;
  color: #666;
  line-height: 1.4;
}

.search-no-results {
  padding: 15px;
  text-align: center;
  color: #888;
  font-size: 1rem;
}

body.dark-mode .nav-link {
  background: rgba(0, 191, 255, 0.1);
}

body.dark-mode .nav-link:hover {
  background: rgba(0, 191, 255, 0.2);
  color: var(--primary-color);
}

body.dark-mode .nav-link:active {
  background: var(--primary-color);
  color: var(--text-color-inverted);
}

body.dark-mode .username-display {
  color: var(--text-color-inverted);
  background: rgba(0, 191, 255, 0.1);
}

body.dark-mode .username-display:hover {
  background: rgba(0, 191, 255, 0.2);
}

body.dark-mode .hero-section {
  background: #222;
}

body.dark-mode .subjects-grid::before {
  background: rgba(0, 212, 255, 0.2);
}

body.dark-mode .section-title {
  color: var(--text-color-inverted);
}

body.dark-mode .subject-card:hover {
  box-shadow: 0 15px 30px rgba(255, 255, 255, 0.2);
}

body.dark-mode .card-link:hover {
  color: #2c2c2c;
}

body.dark-mode .equation-section {
  background: linear-gradient(135deg, rgba(0, 212, 255, 0.3), rgba(255, 0, 255, 0.3));
  border: 1px solid rgba(0, 212, 255, 0.7);
  box-shadow: 0 0 50px rgba(0, 212, 255, 0.6);
}

body.dark-mode .equation-title {
  color: var(--text-color-inverted);
  text-shadow: 0 0 20px rgba(0, 212, 255, 1), 0 0 30px rgba(0, 212, 255, 0.9);
}

body.dark-mode .read-more-btn,
body.dark-mode .read-less-btn {
  box-shadow: 0 0 25px rgba(0, 212, 255, 0.9);
}

body.dark-mode .equation-text p {
  color: var(--text-color);
}

body.dark-mode .futuristic-table th {
  background: linear-gradient(45deg, var(--primary-color-dark-theme), #2c2c2c);
}

body.dark-mode .futuristic-table th,
body.dark-mode .futuristic-table td {
  border: 1px solid rgba(0, 212, 255, 0.5);
}

body.dark-mode .contact-section {
  border: 1px solid rgba(0, 212, 255, 0.7);
  box-shadow: 0 0 50px rgba(0, 212, 255, 0.6);
}

body.dark-mode .contact-cta {
  border: 2px solid var(--primary-color-dark-theme);
  box-shadow: 0 0 25px rgba(0, 212, 255, 0.9);
}

body.dark-mode .app-footer {
  background: linear-gradient(135deg, #2c2c2c, var(--primary-color-dark-theme));
  border-top: 1px solid rgba(0, 212, 255, 0.7);
  box-shadow: 0 -5px 15px rgba(0, 212, 255, 0.4);
}

body.dark-mode .app-footer p {
  text-shadow: 0 0 5px rgba(0, 212, 255, 0.7);
}

body.dark-mode .search-bar:focus {
  box-shadow: 0 4px 20px rgba(0, 191, 255, 0.3);
}

body.dark-mode .search-result-item {
  border-bottom: 1px solid #444;
}

body.dark-mode .search-result-item:hover {
  background: #383838;
}

body.dark-mode .search-no-results {
  color: #aaa;
}

@media (max-width: 1024px) {
  .app-header { padding: 12px 20px; }
  .logo-container .logo { font-size: 28px; }
  .main-nav .nav-list { gap: 16px; }
  .main-nav .nav-link { font-size: 14px; padding: 6px 12px; }
  .auth-btn { padding: 8px 20px; font-size: 14px; }
  .hero-section { padding-top: 100px; }
  .hero-slide { height: 70vh; padding: 20px; }
  .hero-content { max-width: 400px; }
  .hero-slide .hero-title { font-size: 2rem; }
  .hero-slide .hero-text { font-size: 1rem; }
  .subjects-grid { padding: 40px 15px; }
  .cards-container { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 20px; }
  .subject-card { min-height: 200px; }
  .card-title { font-size: 1.6rem; }
  .card-desc { font-size: 1rem; }
  .card-link { font-size: 1rem; padding: 6px 16px; }
  .equation-container { max-width: 900px; }
  .equation-image-wrapper { max-width: 400px; min-height: 300px; }
  .equation-image { max-height: 300px; }
  .search-bar, .search-results { max-width: 500px; }
}

@media (max-width: 768px) {
  .app-header { padding: 8px 10px; }
  .logo-container .logo { font-size: 20px; }
  .main-nav .nav-list { gap: 8px; overflow-x: auto; padding: 0 5px; }
  .main-nav .nav-link { font-size: 12px; padding: 4px 8px; }
  .main-nav .nav-link[href="#home"], .main-nav .nav-link[href="#subjects"] { display: none; }
  .auth-btn { font-size: 12px; padding: 4px 8px; background: rgba(0, 123, 255, 0.1); color: var(--text-color); box-shadow: none; }
  .auth-btn:hover { background: rgba(0, 123, 255, 0.2); color: var(--primary-color); }
  .auth-btn:active { background: var(--primary-color-hover); color: var(--text-color-inverted); }
  body.dark-mode .auth-btn { background: rgba(0, 191, 255, 0.1); color: #ccc; }
  body.dark-mode .auth-btn:hover { background: rgba(0, 191, 255, 0.2); color: var(--primary-color-dark-theme); }
  .dark-mode-toggle { padding: 6px; }
  .mode-icon { width: 32px; height: 32px; }
  .username-display { display: none; }
  .hero-section { padding-top: 60px; }
  .hero-slide { flex-direction: column; height: 60vh; justify-content: center; text-align: center; padding: 15px; }
  .hero-content { max-width: 100%; text-align: center; }
  .hero-slide .hero-title { font-size: 1.8rem; }
  .hero-slide .hero-text { font-size: 0.95rem; }
  .slider-btn { width: 35px; height: 35px; font-size: 1.2rem; }
  .subjects-grid { padding: 30px 10px; }
  .section-title { font-size: 2rem; }
  .cards-container { grid-template-columns: repeat(3, 1fr); gap: 10px; padding: 0 5px; }
  .subject-card { min-height: 140px; border-radius: 10px; box-shadow: 0 3px 10px var(--shadow-main); }
  .card-content { padding: 10px; }
  .card-title { font-size: 1.2rem; margin-bottom: 5px; }
  .card-desc { font-size: 0.8rem; margin-bottom: 8px; }
  .card-link { font-size: 0.8rem; padding: 4px 10px; border-radius: 15px; }
  .equation-section { padding: 20px 10px; margin: 40px 0; }
  .equation-container { flex-direction: column-reverse; text-align: center; }
  .equation-content-wrapper { max-width: 100%; text-align: center; padding: 10px; }
  .equation-image-wrapper { margin-bottom: 15px; max-width: 300px; min-height: 200px; }
  .equation-image { max-height: 200px; }
  .equation-title { font-size: 1.3rem; }
  .read-more-btn, .read-less-btn { padding: 8px 20px; font-size: 1rem; box-shadow: none; }
  .futuristic-table th, .futuristic-table td { font-size: 0.9rem; padding: 12px; }
  .contact-section { padding: 30px 10px; margin: 60px auto; }
  .contact-cta { padding: 10px 20px; font-size: 1rem; box-shadow: none; }
  .search-bar, .search-results { max-width: 90%; }
  .search-bar { padding: 10px 15px; }
  .search-results { max-height: 300px; }
}

@media (max-width: 480px) {
  .app-header { padding: 6px 8px; }
  .logo-container .logo { font-size: 18px; }
  .main-nav .nav-link { font-size: 10px; padding: 3px 6px; }
  .auth-btn { padding: 3px 6px; font-size: 10px; }
  .dark-mode-toggle { padding: 4px; }
  .mode-icon { width: 28px; height: 28px; }
  .username-display { font-size: 12px; padding: 5px 10px; }
  .hero-section { padding-top: 50px; }
  .hero-slide { height: 50vh; padding: 10px; }
  .hero-slide .hero-title { font-size: 1.5rem; }
  .hero-slide .hero-text { font-size: 0.85rem; }
  .slider-btn { width: 30px; height: 30px; font-size: 1rem; }
  .hero-dots { top: 8px; left: 8px; gap: 6px; }
  .dot { width: 6px; height: 6px; }
  .subjects-grid { padding: 20px 5px; }
  .section-title { font-size: 1.8rem; margin-bottom: 20px; }
  .cards-container { gap: 8px; }
  .subject-card { min-height: 120px; }
  .card-title { font-size: 1rem; }
  .card-desc { font-size: 0.7rem; }
  .card-link { font-size: 0.7rem; padding: 3px 8px; }
  .equation-section { padding: 15px 5px; margin: 30px 0; }
  .equation-title { font-size: 1.2rem; }
  .equation-image-wrapper { max-width: 100%; min-height: 180px; }
  .equation-image { max-height: 180px; }
  .equation-text { font-size: 1rem; }
  .equation-text h4 { font-size: 1.3rem; }
  .equation-text ul li { font-size: 0.9rem; }
  .equation-text p { font-size: 0.95rem; }
  .schedule-title { font-size: 1.5rem; }
  .futuristic-table { max-width: 100%; }
  .futuristic-table th, .futuristic-table td { font-size: 0.8rem; padding: 10px; }
  .contact-section { padding: 20px 5px; margin: 40px auto; }
  .contact-cta { padding: 8px 15px; font-size: 0.9rem; }
  .contact-cta .whatsapp-icon { width: 20px; height: 20px; }
  .app-footer { padding: 10px 15px; font-size: 0.8rem; }
  .search-bar { padding: 8px 12px; font-size: 0.95rem; }
  .search-results { max-height: 250px; }
}

@media (max-width: 360px) {
  .app-header { padding: 5px 6px; }
  .logo-container .logo { font-size: 16px; }
  .main-nav .nav-link { font-size: 9px; padding: 2px 5px; }
  .auth-btn { padding: 2px 5px; font-size: 9px; }
  .mode-icon { width: 24px; height: 24px; }
  .hero-slide { height: 45vh; }
  .hero-slide .hero-title { font-size: 1.3rem; }
  .hero-slide .hero-text { font-size: 0.8rem; }
  .slider-btn { width: 25px; height: 25px; font-size: 0.9rem; }
  .section-title { font-size: 1.6rem; }
  .cards-container { gap: 6px; }
  .subject-card { min-height: 100px; }
  .card-title { font-size: 0.9rem; }
  .card-desc { font-size: 0.65rem; }
  .card-link { font-size: 0.65rem; padding: 2px 6px; }
  .equation-title { font-size: 1.1rem; }
  .equation-image { max-height: 160px; }
  .equation-text { font-size: 0.9rem; }
  .equation-text h4 { font-size: 1.2rem; }
  .futuristic-table th, .futuristic-table td { font-size: 0.7rem; padding: 8px; }
  .contact-cta { padding: 6px 12px; font-size: 0.8rem; }
  .contact-cta .whatsapp-icon { width: 18px; height: 18px; }
}

@media (max-width: 768px) {
  .main-nav, .username-display { display: none; }
  .app-header { justify-content: space-between; z-index: 1100; }
  .app-header .logo-container { position: absolute; left: 50%; transform: translateX(-50%); }
  .app-header .dark-mode-toggle { order: -1; }
  .app-header .hamburger-menu { order: 1; }
  .hamburger-menu { display: block; position: relative; z-index: 1201; }
  .hamburger-icon { background: none; border: none; cursor: pointer; display: flex; flex-direction: column; justify-content: space-around; width: 28px; height: 22px; padding: 0; }
  .hamburger-icon span { display: block; width: 100%; height: 3px; background: var(--primary-color); border-radius: 3px; transition: all 0.3s ease-in-out; }
  .hamburger-icon.open span { background: var(--primary-color); }
  .hamburger-icon.open span:nth-child(1) { transform: translateY(9.5px) rotate(45deg); }
  .hamburger-icon.open span:nth-child(2) { opacity: 0; }
  .hamburger-icon.open span:nth-child(3) { transform: translateY(-9.5px) rotate(-45deg); }
  .menu-links { display: flex; flex-direction: column; position: fixed; z-index: 1200; transition: transform 0.4s cubic-bezier(0.23, 1, 0.32, 1), opacity 0.4s ease; transform: translateX(-110%) scale(0.95); opacity: 0; visibility: hidden; top: 75px; left: 15px; height: auto; width: auto; min-width: 280px; border-radius: 16px; background: rgba(44, 62, 80, 0.75); backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px); border: 1px solid rgba(255, 255, 255, 0.15); box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3); padding: 15px; }
  .menu-links.show { transform: translateX(0) scale(1); opacity: 1; visibility: visible; }
  .menu-items { display: flex; flex-direction: column; gap: 8px; width: 100%; }
  .menu-link { display: flex; align-items: center; gap: 15px; width: 100%; text-align: right; padding: 12px 15px; font-size: 16px; border-radius: 8px; border: none; cursor: pointer; font-weight: 500; color: #ecf0f1; background-color: transparent; transition: background-color 0.2s ease, padding-right 0.2s ease; }
  .menu-link:hover { background-color: rgba(0, 212, 255, 0.15); padding-right: 20px; }
  .menu-icon { font-size: 20px; width: 24px; text-align: center; color: var(--primary-color-dark-theme); }
  .menu-divider { border: none; height: 1px; background-color: rgba(255, 255, 255, 0.1); margin: 8px 0; }
  body.dark-mode .hamburger-icon span { background: var(--primary-color-dark-theme); }
  body.dark-mode .hamburger-icon.open span { background: var(--text-color-inverted); }
}

body.menu-open::after {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  z-index: 1099;
  transition: background-color 0.4s;
}

body:not(.menu-open)::after {
  background: rgba(0, 0, 0, 0);
  pointer-events: none;
}

#menu-user-profile {
  display: flex;
  align-items: center;
  gap: 12px;
  padding-bottom: 15px;
  margin-bottom: 15px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.15);
  width: 100%;
}

.menu-user-icon {
  font-size: 24px;
  line-height: 1;
}

#menu-username {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-color-inverted);
  text-shadow: 0 0 5px rgba(0, 212, 255, 0.7);
}

@media (max-width: 768px) {
  #desktop-search-bar { display: none; }
}

.header-left-cluster {
  display: flex;
  align-items: center;
  gap: 16px;
  order: -1;
}

.mobile-search-icon {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 5px;
  color: var(--text-color);
}
body.dark-mode .mobile-search-icon {
  color: var(--text-color);
}
.mobile-search-icon svg {
  width: 22px;
  height: 22px;
}

@media (max-width: 768px) {
  .mobile-search-icon { display: block; }
  .header-left-cluster { order: 0; }
  .app-header .dark-mode-toggle { order: 0; }
}

.mobile-search-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: auto;
  background-color: var(--bg-header);
  z-index: 1500;
  display: none;
  align-items: center;
  padding: 10px 15px;
  box-shadow: 0 4px 10px var(--shadow-main);
  gap: 10px;
}

#mobile-search-input {
  width: 100%;
  border: none;
  outline: none;
  padding: 10px 5px;
  font-size: 1.2rem;
  font-family: var(--font-main);
  background: transparent;
  color: var(--text-color);
}

.close-search-btn {
  background: none;
  border: none;
  font-size: 2.5rem;
  color: #888;
  cursor: pointer;
  padding: 0 10px;
  line-height: 1;
}

#search-results {
  position: absolute;
  top: 65px;
  left: 50%;
  transform: translateX(-50%);
  width: 90%;
  max-width: 550px;
  margin-top: 5px;
  z-index: 1400;
  display: none;
}
#search-results.show {
  display: block;
}

@media (min-width: 769px) {
  #search-results { position: relative; top: auto; left: auto; transform: none; width: 100%; max-width: 600px; margin: 10px auto 40px; z-index: 1000; }
}

.desktop-search-container {
  position: relative;
  max-width: 600px;
  margin: 20px auto 40px;
}

@media (min-width: 769px) {
  #search-results { position: absolute; top: 100%; left: 0; right: 0; z-index: 1000; transform: none; width: 100%; max-width: none; margin-top: 5px; }
}

@media (min-width: 769px) {
  .app-header { justify-content: space-between; align-items: center; gap: 300px; }
  .app-header .logo-container { order: 1; }
  .app-header .header-left-cluster { order: 2; }
  .app-header .main-nav { order: 3; }
  .app-header #usernameDisplay { order: 4; }
  .app-header .main-nav { margin-right: auto; }
  .app-header #usernameDisplay { margin-left: 0; }
  .app-header .logo-container { position: static; transform: none; }
  .main-nav { display: flex; }
  #usernameDisplay.username-display { display: inline-block; }
}