/* ========================================
   COLOR PALETTE & DESIGN TOKENS
   ======================================== */

:root {
  /* Primary Colors */
  --primary-bg: #050816;
  --primary-bg-alt: #070b1f;
  --primary-bg-card: #0a1026;

  /* Accent Colors */
  --accent-blue: #00d9ff;
  --accent-purple: #8b5cf6;
  --accent-violet: #d946ef;
  --accent-cyan: #06b6d4;

  /* Text Colors */
  --text-primary: #ffffff;
  --text-secondary: #c7d2e0;
  --text-tertiary: #8899aa;

  /* Glow & Effects */
  --glow-blue: rgba(0, 217, 255, 0.3);
  --glow-purple: rgba(139, 92, 246, 0.25);
  --glow-violet: rgba(217, 70, 239, 0.2);

  /* Spacing Scale */
  --sp-xs: 4px;
  --sp-sm: 8px;
  --sp-md: 16px;
  --sp-lg: 24px;
  --sp-xl: 32px;
  --sp-2xl: 48px;
  --sp-3xl: 64px;

  /* Border Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.15);
  --shadow-lg: 0 20px 40px rgba(0, 0, 0, 0.3);
  --shadow-glow: 0 0 30px rgba(139, 92, 246, 0.2), 0 0 60px rgba(0, 217, 255, 0.1);

  /* Font Scale */
  --fs-xs: 12px;
  --fs-sm: 14px;
  --fs-base: 16px;
  --fs-lg: 18px;
  --fs-xl: 20px;
  --fs-2xl: 24px;
  --fs-3xl: 28px;
  --fs-4xl: 36px;
  --fs-5xl: 48px;

  /* Line Heights */
  --lh-tight: 1.2;
  --lh-normal: 1.5;
  --lh-relaxed: 1.75;
}

/* ========================================
   GLOBAL STYLES
   ======================================== */

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

html {
  scroll-behavior: smooth;
}

body {
  background: linear-gradient(135deg, var(--primary-bg) 0%, var(--primary-bg-alt) 50%, var(--primary-bg) 100%);
  color: var(--text-primary);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: var(--fs-base);
  line-height: var(--lh-normal);
  letter-spacing: 0.3px;
  overflow-x: hidden;
}

/* Animated background glow effect */
body::before {
  content: "";
  position: fixed;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle, var(--glow-purple) 0%, transparent 70%),
              radial-gradient(circle at 80% 20%, var(--glow-blue) 0%, transparent 60%);
  opacity: 0.15;
  animation: glowShift 8s ease-in-out infinite;
  z-index: 0;
  pointer-events: none;
}

@keyframes glowShift {
  0%, 100% { transform: translate(0, 0); }
  50% { transform: translate(30px, -30px); }
}

/* ========================================
   TYPOGRAPHY
   ======================================== */

h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  letter-spacing: -0.5px;
  color: var(--text-primary);
  line-height: var(--lh-tight);
}

h1 {
  font-size: var(--fs-5xl);
  margin-bottom: var(--sp-md);
}

h2 {
  font-size: var(--fs-4xl);
  margin-bottom: var(--sp-lg);
}

h3 {
  font-size: var(--fs-3xl);
  margin-bottom: var(--sp-md);
}

h4 {
  font-size: var(--fs-2xl);
  margin-bottom: var(--sp-md);
}

p {
  color: var(--text-secondary);
  margin-bottom: var(--sp-md);
  line-height: var(--lh-relaxed);
}

a {
  color: var(--accent-blue);
  text-decoration: none;
  transition: color 0.3s ease;
}

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

/* ========================================
   CONTAINERS & SECTIONS
   ======================================== */

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--sp-lg);
}

section {
  position: relative;
  z-index: 1;
  padding: var(--sp-3xl) 0;
}

section.section-alt {
  background: rgba(10, 16, 38, 0.4);
  backdrop-filter: blur(10px);
}

/* ========================================
   BUTTONS
   ======================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 28px;
  border-radius: var(--radius-full);
  font-size: var(--fs-base);
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  border: none;
  text-decoration: none;
  white-space: nowrap;
  gap: var(--sp-sm);
}

.btn-primary {
  background: var(--accent-blue);
  color: var(--primary-bg);
  box-shadow: 0 0 20px var(--glow-blue);
}

.btn-primary:hover {
  background: var(--accent-cyan);
  box-shadow: 0 0 30px var(--glow-blue), 0 0 50px rgba(0, 217, 255, 0.3);
  transform: translateY(-2px);
}

.btn-secondary {
  background: transparent;
  color: var(--text-primary);
  border: 2px solid rgba(139, 92, 246, 0.4);
  backdrop-filter: blur(10px);
}

.btn-secondary:hover {
  background: rgba(139, 92, 246, 0.1);
  border-color: var(--accent-purple);
  box-shadow: 0 0 20px var(--glow-purple);
}

.btn-ghost {
  background: transparent;
  color: var(--accent-blue);
  border: 1px solid var(--accent-blue);
}

.btn-ghost:hover {
  background: rgba(0, 217, 255, 0.1);
}

.btn-lg {
  padding: 18px 36px;
  font-size: var(--fs-lg);
}

.btn-sm {
  padding: 10px 20px;
  font-size: var(--fs-sm);
}

/* ========================================
   CARDS
   ======================================== */

.card {
  background: rgba(10, 16, 38, 0.5);
  backdrop-filter: blur(20px);
  border: 1px solid rgba(0, 217, 255, 0.1);
  border-radius: var(--radius-lg);
  padding: var(--sp-lg);
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
}

.card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, rgba(139, 92, 246, 0.1) 0%, transparent 100%);
  opacity: 0;
  transition: opacity 0.3s ease;
  z-index: 0;
}

.card:hover {
  border-color: rgba(139, 92, 246, 0.3);
  box-shadow: var(--shadow-glow);
  transform: translateY(-4px);
}

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

.card > * {
  position: relative;
  z-index: 1;
}

.card-title {
  font-size: var(--fs-xl);
  font-weight: 600;
  margin-bottom: var(--sp-md);
  color: var(--text-primary);
}

.card-desc {
  color: var(--text-secondary);
  font-size: var(--fs-sm);
  line-height: var(--lh-relaxed);
}

/* ========================================
   HEADER & NAVIGATION
   ======================================== */

header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(5, 8, 22, 0.7);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(0, 217, 255, 0.05);
  transition: all 0.3s ease;
}

header.scrolled {
  background: rgba(5, 8, 22, 0.95);
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.5);
}

.header-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--sp-md) 0;
}

.logo {
  font-size: var(--fs-2xl);
  font-weight: 800;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: var(--sp-sm);
  text-decoration: none;
}

.logo span {
  background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

nav {
  display: flex;
  align-items: center;
  gap: var(--sp-xl);
}

nav a {
  color: var(--text-secondary);
  font-size: var(--fs-sm);
  font-weight: 500;
  transition: color 0.3s ease;
  position: relative;
}

nav a::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent-blue);
  transition: width 0.3s ease;
}

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

nav a:hover::after {
  width: 100%;
}

.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 6px;
  cursor: pointer;
  background: none;
  border: none;
}

.menu-toggle span {
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  transition: all 0.3s ease;
  border-radius: 1px;
}

/* ========================================
   HERO SECTION
   ======================================== */

.hero {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--sp-3xl);
  align-items: center;
  min-height: 600px;
  padding: var(--sp-3xl) 0;
  position: relative;
}

.hero-content h1 {
  font-size: var(--fs-5xl);
  margin-bottom: var(--sp-lg);
  background: linear-gradient(135deg, var(--text-primary), var(--text-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.1;
}

.hero-content p {
  font-size: var(--fs-lg);
  margin-bottom: var(--sp-2xl);
  color: var(--text-secondary);
}

.hero-buttons {
  display: flex;
  gap: var(--sp-md);
  flex-wrap: wrap;
}

.hero-visual {
  position: relative;
  height: 500px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-glow);
}

/* ========================================
   GRID LAYOUTS
   ======================================== */

.grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--sp-2xl);
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--sp-2xl);
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--sp-xl);
}

/* ========================================
   SECTION HEADERS
   ======================================== */

.section-header {
  text-align: center;
  margin-bottom: var(--sp-3xl);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.section-label {
  color: var(--accent-blue);
  font-size: var(--fs-sm);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: var(--sp-md);
}

.section-header h2 {
  font-size: var(--fs-4xl);
  margin-bottom: var(--sp-md);
}

.section-header p {
  color: var(--text-tertiary);
  font-size: var(--fs-lg);
}

/* ========================================
   FEATURE CARDS
   ======================================== */

.feature-card {
  padding: var(--sp-2xl);
  border-radius: var(--radius-lg);
  background: rgba(10, 16, 38, 0.4);
  border: 1px solid rgba(0, 217, 255, 0.1);
  display: flex;
  flex-direction: column;
  gap: var(--sp-lg);
  transition: all 0.3s ease;
}

.feature-card:hover {
  background: rgba(10, 16, 38, 0.6);
  border-color: var(--accent-purple);
  box-shadow: 0 0 30px var(--glow-purple);
  transform: translateY(-8px);
}

.feature-icon {
  font-size: 32px;
  width: 56px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(139, 92, 246, 0.1);
  border-radius: var(--radius-md);
  border: 1px solid var(--accent-purple);
}

.feature-card h3 {
  margin: 0;
  font-size: var(--fs-xl);
}

.feature-card p {
  margin: 0;
  color: var(--text-tertiary);
}

/* ========================================
   COURSE CARDS
   ======================================== */

.course-card {
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: rgba(10, 16, 38, 0.5);
  border: 1px solid rgba(0, 217, 255, 0.1);
  transition: all 0.3s ease;
  display: flex;
  flex-direction: column;
}

.course-card:hover {
  transform: translateY(-8px);
  border-color: var(--accent-blue);
  box-shadow: 0 20px 40px rgba(0, 217, 255, 0.15);
}

.course-image {
  width: 100%;
  height: 200px;
  object-fit: cover;
  background: linear-gradient(135deg, var(--glow-purple), var(--glow-blue));
}

.course-body {
  padding: var(--sp-lg);
  flex: 1;
  display: flex;
  flex-direction: column;
}

.course-level {
  display: inline-block;
  padding: 4px 12px;
  border-radius: var(--radius-full);
  background: rgba(139, 92, 246, 0.2);
  color: var(--accent-purple);
  font-size: var(--fs-xs);
  font-weight: 600;
  margin-bottom: var(--sp-md);
  width: fit-content;
  text-transform: uppercase;
}

.course-title {
  font-size: var(--fs-lg);
  font-weight: 600;
  margin-bottom: var(--sp-md);
  color: var(--text-primary);
}

.course-desc {
  color: var(--text-tertiary);
  font-size: var(--fs-sm);
  margin-bottom: auto;
  margin-bottom: var(--sp-md);
  line-height: var(--lh-relaxed);
}

.course-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: var(--sp-md);
  border-top: 1px solid rgba(0, 217, 255, 0.1);
}

.course-duration {
  color: var(--text-tertiary);
  font-size: var(--fs-xs);
}

.course-cta {
  color: var(--accent-blue);
  font-weight: 600;
  font-size: var(--fs-sm);
  transition: color 0.3s ease;
}

.course-cta:hover {
  color: var(--accent-cyan);
}

/* ========================================
   TESTIMONIALS
   ======================================== */

.testimonial {
  padding: var(--sp-2xl);
  border-radius: var(--radius-lg);
  background: rgba(10, 16, 38, 0.5);
  border: 1px solid rgba(0, 217, 255, 0.1);
}

.testimonial-content {
  margin-bottom: var(--sp-lg);
  color: var(--text-secondary);
  font-style: italic;
  line-height: var(--lh-relaxed);
}

.testimonial-author {
  display: flex;
  align-items: center;
  gap: var(--sp-md);
}

.testimonial-avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
}

.testimonial-meta h4 {
  margin: 0;
  font-size: var(--fs-base);
  margin-bottom: 2px;
}

.testimonial-meta p {
  margin: 0;
  color: var(--text-tertiary);
  font-size: var(--fs-sm);
}

/* ========================================
   PRICING CARDS
   ======================================== */

.pricing-card {
  border-radius: var(--radius-lg);
  background: rgba(10, 16, 38, 0.5);
  border: 1px solid rgba(0, 217, 255, 0.1);
  padding: var(--sp-2xl);
  display: flex;
  flex-direction: column;
  transition: all 0.3s ease;
  position: relative;
}

.pricing-card.featured {
  border: 2px solid var(--accent-blue);
  background: rgba(0, 217, 255, 0.05);
  transform: scale(1.05);
}

.pricing-card:hover {
  border-color: var(--accent-purple);
  box-shadow: var(--shadow-glow);
}

.pricing-header {
  margin-bottom: var(--sp-xl);
}

.pricing-title {
  font-size: var(--fs-2xl);
  margin-bottom: var(--sp-sm);
}

.pricing-price {
  font-size: var(--fs-4xl);
  font-weight: 700;
  margin-bottom: var(--sp-sm);
}

.pricing-price span {
  font-size: var(--fs-base);
  color: var(--text-tertiary);
}

.pricing-desc {
  color: var(--text-tertiary);
  font-size: var(--fs-sm);
  margin-bottom: var(--sp-2xl);
}

.pricing-features {
  list-style: none;
  margin-bottom: var(--sp-2xl);
  flex: 1;
}

.pricing-features li {
  padding: var(--sp-sm) 0;
  color: var(--text-secondary);
  font-size: var(--fs-sm);
  display: flex;
  align-items: center;
  gap: var(--sp-sm);
}

.pricing-features li::before {
  content: "✓";
  color: var(--accent-blue);
  font-weight: 700;
}

/* ========================================
   FOOTER
   ======================================== */

footer {
  background: rgba(5, 8, 22, 0.8);
  backdrop-filter: blur(20px);
  border-top: 1px solid rgba(0, 217, 255, 0.1);
  color: var(--text-secondary);
  padding: var(--sp-3xl) 0 var(--sp-lg);
}

.footer-content {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: var(--sp-2xl);
  margin-bottom: var(--sp-3xl);
}

.footer-brand h3 {
  font-size: var(--fs-xl);
  color: var(--text-primary);
  margin-bottom: var(--sp-md);
}

.footer-brand p {
  color: var(--text-tertiary);
  font-size: var(--fs-sm);
  line-height: var(--lh-relaxed);
}

.footer-section h4 {
  font-size: var(--fs-base);
  color: var(--text-primary);
  margin-bottom: var(--sp-lg);
  font-weight: 600;
}

.footer-section ul {
  list-style: none;
}

.footer-section ul li {
  margin-bottom: var(--sp-md);
}

.footer-section a {
  color: var(--text-tertiary);
  font-size: var(--fs-sm);
  transition: color 0.3s ease;
}

.footer-section a:hover {
  color: var(--accent-blue);
}

.footer-socials {
  display: flex;
  gap: var(--sp-md);
  margin-top: var(--sp-lg);
}

.social-icon {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid rgba(0, 217, 255, 0.3);
  border-radius: 50%;
  color: var(--accent-blue);
  transition: all 0.3s ease;
}

.social-icon:hover {
  background: rgba(0, 217, 255, 0.1);
  border-color: var(--accent-blue);
}

.footer-divider {
  height: 1px;
  background: rgba(0, 217, 255, 0.1);
  margin-bottom: var(--sp-2xl);
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: var(--fs-sm);
  color: var(--text-tertiary);
  padding-top: var(--sp-lg);
}

/* ========================================
   FORMS
   ======================================== */

.form-group {
  margin-bottom: var(--sp-lg);
}

label {
  display: block;
  margin-bottom: var(--sp-sm);
  color: var(--text-primary);
  font-weight: 500;
  font-size: var(--fs-sm);
}

input[type="text"],
input[type="email"],
input[type="phone"],
textarea {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid rgba(0, 217, 255, 0.2);
  border-radius: var(--radius-md);
  background: rgba(10, 16, 38, 0.5);
  color: var(--text-primary);
  font-size: var(--fs-base);
  font-family: inherit;
  transition: all 0.3s ease;
}

input[type="text"]:focus,
input[type="email"]:focus,
input[type="phone"]:focus,
textarea:focus {
  outline: none;
  border-color: var(--accent-blue);
  box-shadow: 0 0 20px rgba(0, 217, 255, 0.2);
  background: rgba(10, 16, 38, 0.7);
}

textarea {
  resize: vertical;
  min-height: 120px;
}

/* ========================================
   FAQ
   ======================================== */

.faq-item {
  border-bottom: 1px solid rgba(0, 217, 255, 0.1);
  padding: var(--sp-lg) 0;
}

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

.faq-question {
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  color: var(--text-primary);
  font-weight: 600;
  font-size: var(--fs-lg);
  transition: color 0.3s ease;
}

.faq-question:hover {
  color: var(--accent-blue);
}

.faq-toggle {
  font-size: 24px;
  color: var(--accent-blue);
  transition: transform 0.3s ease;
}

.faq-toggle.active {
  transform: rotate(180deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
  color: var(--text-tertiary);
  padding-top: 0;
}

.faq-answer.active {
  max-height: 300px;
  padding-top: var(--sp-lg);
}

/* ========================================
   RESPONSIVE DESIGN
   ======================================== */

@media (max-width: 768px) {
  :root {
    --fs-5xl: 36px;
    --fs-4xl: 28px;
    --fs-3xl: 24px;
  }

  header {
    padding: var(--sp-md) 0;
  }

  .header-content {
    justify-content: space-between;
  }

  nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    background: rgba(5, 8, 22, 0.95);
    backdrop-filter: blur(20px);
    padding: var(--sp-lg);
    gap: var(--sp-md);
    border-bottom: 1px solid rgba(0, 217, 255, 0.1);
  }

  nav.active {
    display: flex;
  }

  .menu-toggle {
    display: flex;
  }

  .hero {
    grid-template-columns: 1fr;
    min-height: auto;
    gap: var(--sp-2xl);
  }

  .hero-content h1 {
    font-size: var(--fs-4xl);
  }

  .hero-visual {
    height: 300px;
  }

  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }

  .pricing-card.featured {
    transform: scale(1);
  }

  .footer-content {
    grid-template-columns: 1fr;
  }

  .footer-bottom {
    flex-direction: column;
    gap: var(--sp-md);
    text-align: center;
  }

  section {
    padding: var(--sp-2xl) 0;
  }

  .section-header h2 {
    font-size: var(--fs-3xl);
  }

  .hero-buttons {
    flex-direction: column;
  }

  .btn {
    width: 100%;
    justify-content: center;
  }
}

@media (max-width: 480px) {
  :root {
    --fs-5xl: 28px;
    --fs-4xl: 24px;
    --sp-3xl: 40px;
  }

  .container {
    padding: 0 var(--sp-md);
  }

  h1 {
    font-size: var(--fs-4xl);
  }

  h2 {
    font-size: var(--fs-3xl);
  }

  .card {
    padding: var(--sp-md);
  }

  .feature-card {
    padding: var(--sp-lg);
  }
}

/* ========================================
   UTILITIES
   ======================================== */

.text-center {
  text-align: center;
}

.text-right {
  text-align: right;
}

.mt-sm { margin-top: var(--sp-sm); }
.mt-md { margin-top: var(--sp-md); }
.mt-lg { margin-top: var(--sp-lg); }
.mt-xl { margin-top: var(--sp-xl); }

.mb-sm { margin-bottom: var(--sp-sm); }
.mb-md { margin-bottom: var(--sp-md); }
.mb-lg { margin-bottom: var(--sp-lg); }
.mb-xl { margin-bottom: var(--sp-xl); }

.pt-lg { padding-top: var(--sp-lg); }
.pb-lg { padding-bottom: var(--sp-lg); }

.gap-sm { gap: var(--sp-sm); }
.gap-md { gap: var(--sp-md); }
.gap-lg { gap: var(--sp-lg); }