/* ===== RESET & BASE ===== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --primary: #01579b;
  --primary-light: #40c4ff;
  --secondary: #00bcd4;
  --accent: #ff6b6b;
  --success: #4caf50;
  --warning: #ffc107;
  --dark: #0d1117;
  --dark-light: #161b22;
  --text: #e6edf3;
  --text-muted: #8b949e;
  --card-bg: rgba(22, 27, 34, 0.8);
  --glass: rgba(255, 255, 255, 0.05);
  --gradient-1: linear-gradient(135deg, #01579b 0%, #40c4ff 100%);
  --gradient-2: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --gradient-3: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
}

body {
  font-family: "Poppins", sans-serif;
  background: var(--dark);
  color: var(--text);
  min-height: 100vh;
  overflow-x: hidden;
}

/* ===== LANDING PAGE ===== */
.landing-page {
  min-height: 100vh;
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 40px 20px;
  position: relative;
  background:
    radial-gradient(
      ellipse at top left,
      rgba(1, 87, 155, 0.2) 0%,
      transparent 50%
    ),
    radial-gradient(
      ellipse at bottom right,
      rgba(64, 196, 255, 0.1) 0%,
      transparent 50%
    ),
    var(--dark);
}

.landing-page.active {
  display: flex;
}

/* Particles Background */
.particles {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  pointer-events: none;
}

.particles::before,
.particles::after {
  content: "";
  position: absolute;
  width: 400px;
  height: 400px;
  border-radius: 50%;
  background: var(--gradient-1);
  opacity: 0.03;
  animation: float 20s infinite ease-in-out;
}

.particles::before {
  top: -100px;
  left: -100px;
}

.particles::after {
  bottom: -100px;
  right: -100px;
  animation-delay: -10s;
}

@keyframes float {
    0%, 100% { transform: translate(0, 0) rotate(0deg) scale(1); }
    33% { transform: translate(30px, -50px) rotate(10deg) scale(1.05); }
    66% { transform: translate(-20px, 20px) rotate(-10deg) scale(0.95); }
}

/* Floating Decorative Icons */
.floating-icons {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    pointer-events: none;
    z-index: 0;
}

.deco-icon {
    position: absolute;
    opacity: 0.15;
    filter: blur(1px) drop-shadow(0 0 20px rgba(64, 196, 255, 0.4));
    transition: all 0.5s ease;
    animation: floatingDeco 15s infinite ease-in-out;
}

.icon-1 {
    width: 250px;
    top: -50px;
    right: -50px;
    animation-duration: 25s;
}

.icon-2 {
    width: 180px;
    bottom: -30px;
    left: -40px;
    animation-duration: 20s;
    animation-delay: -5s;
}

.icon-3 {
    width: 100px;
    top: 40%;
    right: 15%;
    opacity: 0.08;
    animation-duration: 18s;
    animation-delay: -2s;
}

.presentation-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    pointer-events: none;
}

.mini-icon-1 {
    width: 80px;
    top: 100px;
    left: 50px;
    opacity: 0.05;
}

.mini-icon-2 {
    width: 120px;
    bottom: 100px;
    right: 50px;
    opacity: 0.05;
}

@keyframes floatingDeco {
    0%, 100% { transform: translate(0, 0) rotate(0deg); }
    25% { transform: translate(50px, 50px) rotate(15deg); }
    50% { transform: translate(0, 100px) rotate(0deg); }
    75% { transform: translate(-50px, 50px) rotate(-15deg); }
}

/* Logo & Title */
.landing-content {
  max-width: 1200px;
  width: 100%;
  z-index: 1;
}

.logo-container {
  text-align: center;
  margin-bottom: 60px;
}

.dart-logo {
  width: 150px;
  height: 150px;
  margin: 0 auto 30px;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}

.main-logo-img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  position: relative;
  z-index: 3;
  animation: logoFloat 4s infinite ease-in-out;
  filter: drop-shadow(0 0 30px rgba(64, 196, 255, 0.6));
}

.logo-glow {
  position: absolute;
  width: 180px;
  height: 180px;
  background: radial-gradient(circle, rgba(64, 196, 255, 0.4) 0%, transparent 70%);
  border-radius: 50%;
  z-index: 1;
  animation: glowPulse 3s infinite ease-in-out;
}

.logo-ring {
  position: absolute;
  width: 200px;
  height: 200px;
  border: 2px solid rgba(64, 196, 255, 0.3);
  border-radius: 50%;
  z-index: 2;
  animation: ringExpand 4s infinite ease-out;
}

.logo-ring.ring-2 {
  animation-delay: 2s;
}

@keyframes logoFloat {
  0%, 100% {
    transform: translateY(0) scale(1);
    filter: drop-shadow(0 0 30px rgba(64, 196, 255, 0.6));
  }
  50% {
    transform: translateY(-15px) scale(1.05);
    filter: drop-shadow(0 0 50px rgba(64, 196, 255, 0.9));
  }
}

@keyframes glowPulse {
  0%, 100% {
    transform: scale(1);
    opacity: 0.6;
  }
  50% {
    transform: scale(1.2);
    opacity: 0.3;
  }
}

@keyframes ringExpand {
  0% {
    transform: scale(0.8);
    opacity: 1;
  }
  100% {
    transform: scale(1.5);
    opacity: 0;
  }
}

@keyframes pulse {
  0%,
  100% {
    transform: scale(1);
    filter: drop-shadow(0 0 20px rgba(64, 196, 255, 0.3));
  }
  50% {
    transform: scale(1.05);
    filter: drop-shadow(0 0 40px rgba(64, 196, 255, 0.5));
  }
}

.dart-icon {
  width: 100%;
  height: 100%;
}

.main-title {
  font-size: 3rem;
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 15px;
  background: var(--gradient-1);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.main-title .highlight {
  display: block;
  font-size: 3.5rem;
}

.subtitle {
  font-size: 1.2rem;
  color: var(--text-muted);
  font-weight: 400;
}

/* Menu Grid */
.menu-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 25px;
  margin-bottom: 40px;
}

.menu-card {
  background: var(--card-bg);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 20px;
  padding: 30px;
  cursor: pointer;
  transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  position: relative;
  overflow: hidden;
  animation: fadeInUp 0.6s ease forwards;
  animation-delay: var(--delay);
  opacity: 0;
  transform: translateY(30px);
}

@keyframes fadeInUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.menu-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--gradient-1);
  opacity: 0;
  transition: opacity 0.3s;
}

.menu-card:hover {
  transform: translateY(-10px) scale(1.02);
  border-color: var(--primary-light);
  box-shadow:
    0 20px 40px rgba(0, 0, 0, 0.3),
    0 0 30px rgba(64, 196, 255, 0.2);
}

.menu-card:hover::before {
  opacity: 0.1;
}

.card-icon {
  font-size: 3rem;
  margin-bottom: 15px;
  display: block;
}

.menu-card h3 {
  font-size: 1.3rem;
  font-weight: 600;
  margin-bottom: 10px;
  color: var(--text);
  position: relative;
  z-index: 1;
}

.menu-card p {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.5;
  position: relative;
  z-index: 1;
}

.card-arrow {
  position: absolute;
  bottom: 25px;
  right: 25px;
  font-size: 1.5rem;
  color: var(--primary-light);
  opacity: 0;
  transform: translateX(-10px);
  transition: all 0.3s;
}

.menu-card:hover .card-arrow {
  opacity: 1;
  transform: translateX(0);
}

.footer-info {
  text-align: center;
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* ===== PRESENTATION CONTAINER ===== */
.presentation-container {
  display: none;
  flex-direction: column;
  min-height: 100vh;
  background: var(--dark);
}

.presentation-container.active {
  display: flex;
}

/* Navigation */
.presentation-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 15px 30px;
  background: var(--dark-light);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav-btn {
  background: var(--glass);
  border: 1px solid rgba(255, 255, 255, 0.1);
  color: var(--text);
  padding: 10px 20px;
  border-radius: 10px;
  cursor: pointer;
  font-family: inherit;
  font-size: 0.9rem;
  transition: all 0.3s;
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-btn:hover {
  background: var(--primary);
  border-color: var(--primary);
  transform: translateY(-2px);
}

.home-btn {
  background: var(--gradient-1);
  border: none;
}

.slide-info {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 5px;
}

.slide-info #currentTopic {
  font-weight: 600;
  color: var(--primary-light);
}

.slide-counter {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.nav-controls {
  display: flex;
  gap: 10px;
}

/* Slides Wrapper */
.slides-wrapper {
  flex: 1;
  display: flex;
  overflow: hidden;
  position: relative;
}

.slide {
  min-width: 100%;
  height: calc(100vh - 120px);
  padding: 40px 60px;
  display: none;
  flex-direction: column;
  overflow-y: auto;
  animation: slideIn 0.5s ease;
}

.slide.active {
  display: flex;
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateX(50px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

/* Slide Content Styles */
.slide-header {
  margin-bottom: 40px;
  text-align: center;
}

.slide-header h2 {
  font-size: 2.5rem;
  font-weight: 700;
  background: var(--gradient-1);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 10px;
}

.slide-header .slide-subtitle {
  font-size: 1.1rem;
  color: var(--text-muted);
}

.slide-content {
  flex: 1;
  max-width: 1200px;
  margin: 0 auto;
  width: 100%;
}

/* Info Box Styles */
.info-box {
  background: var(--card-bg);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 15px;
  padding: 25px;
  margin-bottom: 25px;
}

.info-box.highlight {
  border-left: 4px solid var(--primary-light);
}

.info-box h3 {
  font-size: 1.3rem;
  color: var(--primary-light);
  margin-bottom: 15px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.info-box ul {
  list-style: none;
  padding-left: 0;
}

.info-box li {
  padding: 8px 0;
  display: flex;
  align-items: flex-start;
  gap: 12px;
  color: var(--text);
  font-size: 1rem;
  line-height: 1.6;
}

.info-box li::before {
  content: "▸";
  color: var(--primary-light);
  font-weight: bold;
}

/* Code Block Styles */
.code-block {
  background: #0d1117;
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 12px;
  overflow: hidden;
  margin: 20px 0;
}

.code-header {
  background: rgba(255, 255, 255, 0.05);
  padding: 10px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.code-header span {
  color: var(--text-muted);
  font-size: 0.85rem;
}

.code-header .lang-badge {
  background: var(--primary);
  color: white;
  padding: 3px 10px;
  border-radius: 5px;
  font-size: 0.75rem;
  font-weight: 600;
}

.code-content {
  padding: 20px;
  overflow-x: auto;
}

.code-content pre {
  font-family: "Fira Code", monospace;
  font-size: 0.9rem;
  line-height: 1.6;
  color: var(--text);
  white-space: pre-wrap;
  word-wrap: break-word;
}

/* Syntax Highlighting */
.keyword {
  color: #ff79c6;
}
.type {
  color: #8be9fd;
}
.string {
  color: #f1fa8c;
}
.number {
  color: #bd93f9;
}
.comment {
  color: #6272a4;
  font-style: italic;
}
.function {
  color: #50fa7b;
}
.operator {
  color: #ff79c6;
}
.variable {
  color: #f8f8f2;
}

/* Output Box */
.output-box {
  background: #1a1f25;
  border: 1px solid rgba(76, 175, 80, 0.3);
  border-left: 4px solid var(--success);
  border-radius: 12px;
  padding: 20px;
  margin: 20px 0;
}

.output-box h4 {
  color: var(--success);
  margin-bottom: 15px;
  font-size: 0.95rem;
  display: flex;
  align-items: center;
  gap: 8px;
}

.output-box pre {
  font-family: "Fira Code", monospace;
  font-size: 0.85rem;
  color: var(--text);
  line-height: 1.5;
  white-space: pre-wrap;
}

/* Two Column Layout */
.two-columns {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
  gap: 30px;
}

/* Table Styles */
.table-container {
  overflow-x: auto;
  margin: 20px 0;
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--card-bg);
  border-radius: 12px;
  overflow: hidden;
}

.data-table th,
.data-table td {
  padding: 15px 20px;
  text-align: left;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.data-table th {
  background: rgba(1, 87, 155, 0.3);
  color: var(--primary-light);
  font-weight: 600;
  font-size: 0.95rem;
}

.data-table td {
  font-size: 0.9rem;
}

.data-table tr:hover td {
  background: rgba(255, 255, 255, 0.02);
}

.data-table code {
  background: rgba(255, 255, 255, 0.1);
  padding: 3px 8px;
  border-radius: 5px;
  font-family: "Fira Code", monospace;
  font-size: 0.85rem;
  color: var(--primary-light);
}

/* Progress Bar */
.slide-progress {
  height: 4px;
  background: rgba(255, 255, 255, 0.1);
}

.progress-bar {
  height: 100%;
  background: var(--gradient-1);
  width: 0%;
  transition: width 0.3s ease;
}

/* Alert Boxes */
.alert {
  padding: 20px;
  border-radius: 12px;
  margin: 20px 0;
  display: flex;
  align-items: flex-start;
  gap: 15px;
}

.alert-icon {
  font-size: 1.5rem;
  flex-shrink: 0;
}

.alert-info {
  background: rgba(33, 150, 243, 0.1);
  border: 1px solid rgba(33, 150, 243, 0.3);
}

.alert-warning {
  background: rgba(255, 193, 7, 0.1);
  border: 1px solid rgba(255, 193, 7, 0.3);
}

.alert-success {
  background: rgba(76, 175, 80, 0.1);
  border: 1px solid rgba(76, 175, 80, 0.3);
}

/* Responsive */
@media (max-width: 768px) {
  .main-title {
    font-size: 2rem;
  }

  .main-title .highlight {
    font-size: 2.5rem;
  }

  .menu-grid {
    grid-template-columns: 1fr;
  }

  .presentation-nav {
    flex-direction: column;
    gap: 15px;
    padding: 15px;
  }

  .nav-controls {
    width: 100%;
    justify-content: space-between;
  }

  .slide {
    padding: 20px;
  }

  .slide-header h2 {
    font-size: 1.8rem;
  }

  .two-columns {
    grid-template-columns: 1fr;
  }

  .objective-grid {
    grid-template-columns: 1fr;
  }
}

/* Keyboard hints */
.keyboard-hints {
  position: fixed;
  bottom: 20px;
  right: 20px;
  background: var(--card-bg);
  padding: 10px 15px;
  border-radius: 10px;
  font-size: 0.8rem;
  color: var(--text-muted);
  display: flex;
  gap: 15px;
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.key {
  background: rgba(255, 255, 255, 0.1);
  padding: 3px 8px;
  border-radius: 5px;
  font-family: "Fira Code", monospace;
}

/* Learning objectives */
.learning-objectives {
  width: 100%;
  margin: -20px 0 38px;
  padding: 24px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 20px;
  background: rgba(22, 27, 34, 0.72);
  backdrop-filter: blur(14px);
}

.learning-objectives h2 {
  margin-bottom: 18px;
  color: var(--primary-light);
  font-size: 1.5rem;
  text-align: center;
}

.objective-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
}

.objective-grid article {
  padding: 16px;
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.045);
}

.objective-grid strong,
.objective-grid span {
  display: block;
}

.objective-grid strong {
  margin-bottom: 8px;
  color: var(--text);
}

.objective-grid span {
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1.55;
}

/* Feature Cards */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 20px;
  margin: 20px 0;
}

.feature-card {
  background: var(--card-bg);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 15px;
  padding: 25px;
  text-align: center;
  transition: all 0.3s;
}

.feature-card:hover {
  transform: translateY(-5px);
  border-color: var(--primary-light);
}

.feature-card .icon {
  font-size: 2.5rem;
  margin-bottom: 15px;
}

.feature-card h4 {
  color: var(--primary-light);
  margin-bottom: 10px;
}

.feature-card p {
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* Task Cards */
.task-card {
  background: var(--card-bg);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 15px;
  padding: 30px;
  margin: 20px 0;
}

.task-card h3 {
  color: var(--primary-light);
  font-size: 1.4rem;
  margin-bottom: 15px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.task-card .description {
  color: var(--text);
  margin-bottom: 20px;
  line-height: 1.6;
}

.task-card .specs {
  background: rgba(255, 255, 255, 0.03);
  padding: 20px;
  border-radius: 10px;
  margin-top: 15px;
}

.task-card .specs h4 {
  color: var(--warning);
  margin-bottom: 10px;
}

.task-card .specs ul {
  list-style: none;
}

.task-card .specs li {
  padding: 5px 0;
  color: var(--text-muted);
}

@media (max-width: 900px) {
  .objective-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 560px) {
  .objective-grid {
    grid-template-columns: 1fr;
  }
}

.task-card .specs li::before {
  content: "✓ ";
  color: var(--success);
}