/* ===== ROOT VARIABLES ===== */
:root {
  --dart-blue: #0175c2;
  --dart-blue-dark: #02569b;
  --dart-light-blue: #13b9fd;
  --dart-teal: #1de9b6;
  --bg-dark: #0a0e17;
  --bg-gradient: linear-gradient(135deg, #0a0e17 0%, #1a1f35 50%, #0a0e17 100%);
  --card-bg: rgba(255, 255, 255, 0.03);
  --card-border: rgba(255, 255, 255, 0.1);
  --text-primary: #ffffff;
  --text-secondary: rgba(255, 255, 255, 0.7);
  --text-muted: rgba(255, 255, 255, 0.5);
  --shadow-glow: 0 0 40px rgba(1, 117, 194, 0.3);
  --shadow-card: 0 8px 32px rgba(0, 0, 0, 0.3);
}

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

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

/* Learning objectives */
.learning-objectives {
  width: min(1100px, calc(100% - 32px));
  margin: 0 auto 2rem;
  padding: 1.5rem;
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.06);
  backdrop-filter: blur(14px);
}

.learning-objectives h2 {
  margin: 0 0 1rem;
  color: #13b9fd;
  text-align: center;
}

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

.objective-grid article {
  padding: 1rem;
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.045);
}

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

.objective-grid strong {
  margin-bottom: 0.5rem;
}

.objective-grid span {
  color: rgba(255, 255, 255, 0.72);
  font-size: 0.9rem;
  line-height: 1.55;
}

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

html {
  scroll-behavior: smooth;
}

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

/* ===== FLOATING ICONS BACKGROUND ===== */
.floating-icons {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 0;
  overflow: hidden;
}

.float-icon {
  position: absolute;
  width: 60px;
  height: 60px;
  opacity: 0.08;
  animation: floatAnimation 8s ease-in-out infinite;
  filter: blur(1px);
}

@keyframes floatAnimation {
  0%,
  100% {
    transform: translateY(0) rotate(0deg);
  }
  25% {
    transform: translateY(-20px) rotate(5deg);
  }
  50% {
    transform: translateY(-10px) rotate(-5deg);
  }
  75% {
    transform: translateY(-25px) rotate(3deg);
  }
}

/* ===== LANDING PAGE ===== */
.landing-page {
  min-height: 100vh;
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 2rem;
  background: var(--bg-gradient);
  position: relative;
  z-index: 1;
}

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

.landing-container {
  max-width: 1200px;
  width: 100%;
  text-align: center;
}

/* ===== HERO SECTION ===== */
.hero-section {
  margin-bottom: 3rem;
  animation: fadeInUp 1s ease-out;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.main-icon-container {
  position: relative;
  display: inline-block;
  margin-bottom: 2rem;
}

.main-dart-icon {
  width: 120px;
  height: 120px;
  filter: drop-shadow(0 0 30px rgba(1, 117, 194, 0.5));
  animation: pulse 3s ease-in-out infinite;
}

.icon-glow {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 180px;
  height: 180px;
  background: radial-gradient(
    circle,
    rgba(1, 117, 194, 0.3) 0%,
    transparent 70%
  );
  border-radius: 50%;
  animation: glowPulse 3s ease-in-out infinite;
}

@keyframes pulse {
  0%,
  100% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.05);
  }
}

@keyframes glowPulse {
  0%,
  100% {
    opacity: 0.5;
    transform: translate(-50%, -50%) scale(1);
  }
  50% {
    opacity: 1;
    transform: translate(-50%, -50%) scale(1.2);
  }
}

.title {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.title-line {
  font-size: 1.2rem;
  font-weight: 500;
  color: var(--dart-light-blue);
  letter-spacing: 4px;
  text-transform: uppercase;
}

.title-main {
  font-size: 3.5rem;
  font-weight: 800;
  background: linear-gradient(
    135deg,
    var(--dart-blue) 0%,
    var(--dart-light-blue) 50%,
    var(--dart-teal) 100%
  );
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  text-shadow: none;
  line-height: 1.2;
}

.title-sub {
  font-size: 1.8rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.subtitle {
  font-size: 1.1rem;
  color: var(--text-muted);
  max-width: 600px;
  margin: 0 auto;
  line-height: 1.6;
}

/* ===== TOPICS GRID ===== */
.topics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.5rem;
  margin: 3rem 0;
  animation: fadeInUp 1s ease-out 0.3s backwards;
}

.topic-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 20px;
  padding: 2rem;
  position: relative;
  cursor: pointer;
  transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  overflow: hidden;
}

.topic-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    135deg,
    rgba(1, 117, 194, 0.1) 0%,
    transparent 100%
  );
  opacity: 0;
  transition: opacity 0.4s ease;
}

.topic-card:hover {
  transform: translateY(-10px);
  border-color: var(--dart-blue);
  box-shadow: var(--shadow-glow);
}

.topic-card:hover::before {
  opacity: 1;
}

.card-icon {
  width: 70px;
  height: 70px;
  background: linear-gradient(
    135deg,
    var(--dart-blue) 0%,
    var(--dart-light-blue) 100%
  );
  border-radius: 18px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 1.5rem;
  font-size: 1.8rem;
  color: white;
  box-shadow: 0 10px 30px rgba(1, 117, 194, 0.3);
  transition: transform 0.4s ease;
}

.topic-card:hover .card-icon {
  transform: scale(1.1) rotate(5deg);
}

.topic-card h3 {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
}

.topic-card p {
  font-size: 0.95rem;
  color: var(--text-muted);
}

.card-number {
  position: absolute;
  top: 1rem;
  right: 1rem;
  font-size: 2.5rem;
  font-weight: 800;
  color: rgba(1, 117, 194, 0.15);
  line-height: 1;
}

/* ===== START BUTTON ===== */
.start-btn-container {
  animation: fadeInUp 1s ease-out 0.6s backwards;
}

.start-btn {
  display: inline-flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem 2.5rem;
  background: linear-gradient(
    135deg,
    var(--dart-blue) 0%,
    var(--dart-light-blue) 100%
  );
  border: none;
  border-radius: 50px;
  color: white;
  font-family: "Poppins", sans-serif;
  font-size: 1.1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.4s ease;
  box-shadow: 0 10px 40px rgba(1, 117, 194, 0.4);
}

.start-btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 15px 50px rgba(1, 117, 194, 0.5);
}

.start-btn i {
  transition: transform 0.3s ease;
}

.start-btn:hover i {
  transform: translateX(5px);
}

/* ===== SLIDES SECTION ===== */
.slides-section {
  display: none;
  min-height: 100vh;
  flex-direction: column;
  background: var(--bg-gradient);
  position: relative;
  z-index: 1;
}

.slides-section.active {
  display: flex;
}

/* ===== SLIDE HEADER ===== */
.slide-header {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  padding: 1rem 2rem;
  background: rgba(0, 0, 0, 0.3);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--card-border);
}

.home-btn {
  width: 45px;
  height: 45px;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 12px;
  color: var(--text-primary);
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
}

.home-btn:hover {
  background: var(--dart-blue);
  border-color: var(--dart-blue);
}

.progress-container {
  flex: 1;
  height: 8px;
  background: var(--card-bg);
  border-radius: 10px;
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  width: 0%;
  background: linear-gradient(
    90deg,
    var(--dart-blue) 0%,
    var(--dart-light-blue) 100%
  );
  border-radius: 10px;
  transition: width 0.4s ease;
}

.slide-counter {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-secondary);
  min-width: 60px;
  text-align: right;
}

/* ===== SLIDES WRAPPER ===== */
.slides-wrapper {
  flex: 1;
  overflow: hidden;
  position: relative;
}

.slide {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: none;
  opacity: 0;
  padding: 2rem 3rem;
  overflow-y: auto;
  transition:
    opacity 0.5s ease,
    transform 0.5s ease;
}

.slide.active {
  display: block;
  opacity: 1;
}

.slide.slide-enter {
  transform: translateX(100%);
}

.slide.slide-enter-active {
  transform: translateX(0);
}

.slide.slide-exit {
  transform: translateX(0);
}

.slide.slide-exit-active {
  transform: translateX(-100%);
}

/* ===== SLIDE CONTENT ===== */
.slide-content {
  max-width: 1000px;
  margin: 0 auto;
  animation: slideIn 0.6s ease-out;
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.slide-header-content {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.slide-icon {
  width: 60px;
  height: 60px;
  background: linear-gradient(
    135deg,
    var(--dart-blue) 0%,
    var(--dart-light-blue) 100%
  );
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  color: white;
  box-shadow: 0 10px 30px rgba(1, 117, 194, 0.3);
}

.slide-title-group {
  flex: 1;
}

.slide-category {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--dart-light-blue);
  text-transform: uppercase;
  letter-spacing: 2px;
  margin-bottom: 0.3rem;
}

.slide-title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.3;
}

/* ===== CODE BLOCKS ===== */
.code-block {
  background: #1e1e1e;
  border-radius: 16px;
  margin: 1.5rem 0;
  overflow: hidden;
  box-shadow: var(--shadow-card);
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.code-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.8rem 1.2rem;
  background: rgba(0, 0, 0, 0.3);
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.code-dots {
  display: flex;
  gap: 8px;
}

.code-dots span {
  width: 12px;
  height: 12px;
  border-radius: 50%;
}

.code-dots span:nth-child(1) {
  background: #ff5f56;
}
.code-dots span:nth-child(2) {
  background: #ffbd2e;
}
.code-dots span:nth-child(3) {
  background: #27ca40;
}

.code-lang {
  font-size: 0.8rem;
  color: var(--text-muted);
  font-weight: 500;
}

.code-content {
  padding: 1.2rem 1.5rem;
  overflow-x: auto;
}

.code-content pre {
  margin: 0;
  font-family: "Fira Code", "Consolas", monospace;
  font-size: 0.9rem;
  line-height: 1.7;
  color: #e0e0e0;
  white-space: pre;
}

/* Code syntax highlighting */
.keyword {
  color: #c586c0;
}
.type {
  color: #4ec9b0;
}
.function {
  color: #dcdcaa;
}
.string {
  color: #ce9178;
}
.number {
  color: #b5cea8;
}
.comment {
  color: #6a9955;
  font-style: italic;
}
.variable {
  color: #9cdcfe;
}
.operator {
  color: #d4d4d4;
}

/* ===== INFO BOXES ===== */
.info-box {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 16px;
  padding: 1.5rem;
  margin: 1.5rem 0;
  position: relative;
  overflow: hidden;
}

.info-box::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 4px;
  background: linear-gradient(
    180deg,
    var(--dart-blue) 0%,
    var(--dart-light-blue) 100%
  );
}

.info-box.tip::before {
  background: linear-gradient(180deg, #27ca40 0%, #1de9b6 100%);
}

.info-box.warning::before {
  background: linear-gradient(180deg, #ffbd2e 0%, #ff9500 100%);
}

.info-box-title {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  font-size: 1rem;
  font-weight: 600;
  color: var(--dart-light-blue);
  margin-bottom: 0.8rem;
}

.info-box.tip .info-box-title {
  color: #27ca40;
}

.info-box.warning .info-box-title {
  color: #ffbd2e;
}

.info-box p,
.info-box ul {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

.info-box ul {
  padding-left: 1.5rem;
}

.info-box li {
  margin-bottom: 0.5rem;
}

/* ===== TEXT CONTENT ===== */
.text-content {
  font-size: 1.05rem;
  color: var(--text-secondary);
  line-height: 1.8;
  margin: 1.5rem 0;
}

.text-content strong {
  color: var(--text-primary);
  font-weight: 600;
}

.highlight {
  color: var(--dart-light-blue);
  font-weight: 600;
}

/* ===== FEATURE LIST ===== */
.feature-list {
  display: grid;
  gap: 1rem;
  margin: 1.5rem 0;
}

.feature-item {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  padding: 1.2rem;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 12px;
  transition: all 0.3s ease;
}

.feature-item:hover {
  border-color: var(--dart-blue);
  transform: translateX(5px);
}

.feature-icon {
  width: 45px;
  height: 45px;
  background: linear-gradient(
    135deg,
    var(--dart-blue) 0%,
    var(--dart-light-blue) 100%
  );
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 1.1rem;
  flex-shrink: 0;
}

.feature-text h4 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.3rem;
}

.feature-text p {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* ===== DIAGRAM BOX ===== */
.diagram-box {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 16px;
  padding: 2rem;
  margin: 1.5rem 0;
  text-align: center;
}

.diagram-title {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--dart-light-blue);
  margin-bottom: 1.5rem;
}

.diagram-flow {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.diagram-node {
  padding: 0.8rem 1.5rem;
  background: linear-gradient(
    135deg,
    var(--dart-blue) 0%,
    var(--dart-light-blue) 100%
  );
  border-radius: 10px;
  color: white;
  font-weight: 600;
  font-size: 0.95rem;
  box-shadow: 0 5px 20px rgba(1, 117, 194, 0.3);
}

.diagram-arrow {
  color: var(--dart-light-blue);
  font-size: 1.5rem;
}

/* ===== SLIDE NAVIGATION ===== */
.slide-navigation {
  display: flex;
  justify-content: space-between;
  padding: 1rem 2rem;
  background: rgba(0, 0, 0, 0.3);
  backdrop-filter: blur(10px);
  border-top: 1px solid var(--card-border);
}

.nav-btn {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  padding: 0.8rem 1.5rem;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 12px;
  color: var(--text-primary);
  font-family: "Poppins", sans-serif;
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.3s ease;
}

.nav-btn:hover:not(:disabled) {
  background: var(--dart-blue);
  border-color: var(--dart-blue);
  transform: translateY(-2px);
}

.nav-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.next-btn {
  background: linear-gradient(
    135deg,
    var(--dart-blue) 0%,
    var(--dart-light-blue) 100%
  );
  border: none;
}

/* ===== COMPARISON TABLE ===== */
.comparison-table {
  width: 100%;
  margin: 1.5rem 0;
  border-collapse: collapse;
  background: var(--card-bg);
  border-radius: 16px;
  overflow: hidden;
  border: 1px solid var(--card-border);
}

.comparison-table th,
.comparison-table td {
  padding: 1rem 1.2rem;
  text-align: left;
  border-bottom: 1px solid var(--card-border);
}

.comparison-table th {
  background: rgba(1, 117, 194, 0.2);
  font-weight: 600;
  color: var(--dart-light-blue);
  font-size: 0.95rem;
}

.comparison-table td {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

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

.comparison-table tr:hover td {
  background: rgba(1, 117, 194, 0.05);
}

/* ===== RESPONSIVE ===== */
@media (max-width: 768px) {
  .title-main {
    font-size: 2.2rem;
  }

  .title-sub {
    font-size: 1.2rem;
  }

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

  .slide {
    padding: 1.5rem;
  }

  .slide-title {
    font-size: 1.5rem;
  }

  .slide-navigation {
    padding: 1rem;
  }

  .nav-btn span {
    display: none;
  }

  .diagram-flow {
    flex-direction: column;
  }

  .diagram-arrow {
    transform: rotate(90deg);
  }
}

/* ===== SCROLLBAR ===== */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-dark);
}

::-webkit-scrollbar-thumb {
  background: var(--dart-blue);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--dart-light-blue);
}

/* ===== TWO COLUMN LAYOUT ===== */
.two-column {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
  margin: 1.5rem 0;
}

@media (max-width: 768px) {
  .two-column {
    grid-template-columns: 1fr;
  }
}

/* ===== STEP LIST ===== */
.step-list {
  margin: 1.5rem 0;
}

.step-item {
  display: flex;
  gap: 1rem;
  margin-bottom: 1.5rem;
  position: relative;
}

.step-item:not(:last-child)::before {
  content: "";
  position: absolute;
  left: 22px;
  top: 50px;
  width: 2px;
  height: calc(100% - 20px);
  background: linear-gradient(180deg, var(--dart-blue), transparent);
}

.step-number {
  width: 45px;
  height: 45px;
  background: linear-gradient(
    135deg,
    var(--dart-blue) 0%,
    var(--dart-light-blue) 100%
  );
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: 700;
  font-size: 1.1rem;
  flex-shrink: 0;
}

.step-content h4 {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.4rem;
}

.step-content p {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* ===== RESULT BOX ===== */
.result-box {
  background: linear-gradient(
    135deg,
    rgba(39, 202, 64, 0.1) 0%,
    rgba(29, 233, 182, 0.1) 100%
  );
  border: 1px solid rgba(39, 202, 64, 0.3);
  border-radius: 12px;
  padding: 1.2rem;
  margin: 1rem 0;
}

.result-box .result-title {
  font-size: 0.85rem;
  font-weight: 600;
  color: #27ca40;
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.result-box .result-content {
  font-family: "Fira Code", monospace;
  font-size: 0.9rem;
  color: var(--text-secondary);
  white-space: pre-wrap;
}

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

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