@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&display=swap');

:root {
  --bg-dark: #0a0e27;
  --bg-darker: #060818;
  --card-bg: rgba(15, 21, 48, 0.75);
  --border: rgba(255, 255, 255, 0.08);
  --text: #e8f2ff;
  --text-secondary: #a0aec0;
  --accent: #6BEF8B;
  --accent-dark: #30D158;
  --accent-light: #a8f5c4;
  --danger: #ff6b6b;
  --success: #6BEF8B;
  --radius: 12px;
  --radius-lg: 16px;
  --shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
  --shadow-sm: 0 10px 30px rgba(0, 0, 0, 0.3);
  --ff: 'Inter', system-ui, -apple-system, sans-serif;
}

body.light-mode {
  --bg-dark: #ffffff;
  --bg-darker: #f8fafc;
  --card-bg: rgba(255, 255, 255, 0.8);
  --border: rgba(0, 0, 0, 0.08);
  --text: #0a0e27;
  --text-secondary: #475569;
  --accent: #6BEF8B;
  --accent-dark: #30D158;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--ff);
  background: linear-gradient(180deg, var(--bg-darker) 0%, var(--bg-dark) 100%);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background 0.3s ease;
}

/* TYPOGRAPHY */
h1, h2, h3, h4, h5, h6 { font-weight: 700; line-height: 1.2; margin-bottom: 16px; }
h1 { font-size: 56px; letter-spacing: -0.02em; color: var(--text); }
h2 { font-size: 42px; letter-spacing: -0.01em; color: var(--text); margin-bottom: 24px; }
h3 { font-size: 28px; color: var(--text); margin-bottom: 12px; }
h4 { font-size: 20px; color: var(--text); }
p { color: var(--text-secondary); margin-bottom: 12px; line-height: 1.8; }
a { color: var(--accent); text-decoration: none; transition: all 0.2s; }
a:hover { color: var(--accent-dark); }

.container { max-width: 1280px; margin: 0 auto; padding: 0 24px; }
section { padding: 80px 0; }

section:nth-child(odd) {
  background: linear-gradient(180deg, transparent 0%, rgba(107, 239, 139, 0.02) 50%, transparent 100%);
}

/* HEADER */
header,
.navbar {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: linear-gradient(180deg, rgba(10, 14, 30, 0.95), transparent);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
  transition: all 0.3s ease;
}

body.light-mode header,
body.light-mode .navbar {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.95), transparent);
}

.navbar {
  position: relative;
}

.navbar > .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding-top: 16px;
  padding-bottom: 16px;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--accent);
  font-weight: 800;
  font-size: 20px;
  text-decoration: none;
  transition: transform 0.2s;
}

.nav-brand:hover { transform: scale(1.05); }

.nav-menu {
  display: flex;
  gap: 32px;
  list-style: none;
  align-items: center;
  flex: 1;
  justify-content: center;
}

.nav-menu a {
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 14px;
  padding: 6px 0;
  border-bottom: 2px solid transparent;
  transition: all 0.2s;
}

.nav-menu a:hover { color: var(--accent); border-bottom-color: var(--accent); }

.theme-toggle {
  background: var(--accent);
  border: 2px solid var(--accent);
  padding: 8px 14px;
  border-radius: 999px;
  color: #071025;
  cursor: pointer;
  font-weight: 700;
  font-size: 16px;
  transition: all 0.3s;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
}

.theme-toggle:hover { 
  transform: scale(1.1);
  box-shadow: 0 8px 20px rgba(107, 239, 139, 0.3);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  margin-left: auto;
}

.nav-toggle span {
  width: 24px;
  height: 2.5px;
  background: var(--accent);
  border-radius: 2px;
  transition: all 0.3s ease;
  display: block;
}

.nav-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(9px, 9px);
}

.nav-toggle.active span:nth-child(2) {
  opacity: 0;
  transform: translateX(-10px);
}

.nav-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(9px, -9px);
}

/* BUTTONS */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 14px;
  border: none;
  cursor: pointer;
  transition: all 0.3s;
  text-decoration: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-dark));
  color: #071025;
  box-shadow: 0 8px 24px rgba(107, 239, 139, 0.25);
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 14px 40px rgba(107, 239, 139, 0.4);
  color: #071025;
}

.btn-secondary {
  background: transparent;
  color: var(--accent);
  border: 2px solid var(--accent);
}

.btn-secondary:hover { 
  background: rgba(107, 239, 139, 0.15);
  transform: translateY(-2px);
}

.btn-lg { padding: 16px 32px; font-size: 16px; }

/* HERO */
.hero {
  padding: 120px 0;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -10%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(107, 239, 139, 0.12) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
  z-index: 0;
}

.hero .container {
  position: relative;
  z-index: 1;
}

.hero-centered {
  text-align: center;
  max-width: 800px;
  margin: 0 auto;
}

.hero-centered h1 { font-size: 56px; margin-bottom: 20px; color: var(--text); }
.hero-subtitle { font-size: 18px; color: var(--text-secondary); margin-bottom: 32px; line-height: 1.8; }
.hero-ctas { display: flex; gap: 16px; flex-wrap: wrap; justify-content: center; }

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

/* SECTIONS */
.section-title {
  text-align: center;
  margin-bottom: 60px;
}

.section-title h2 { font-size: 42px; margin-bottom: 16px; }
.section-title p { font-size: 18px; color: var(--text-secondary); max-width: 600px; margin: 0 auto; }

/* GRIDS */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.courses-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
}

/* CARDS */
.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  transition: all 0.3s;
  backdrop-filter: blur(10px);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.25);
  position: relative;
  overflow: hidden;
}

body.light-mode .card {
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--accent), var(--accent-dark));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.3s;
}

.card:hover {
  border-color: var(--accent);
  transform: translateY(-12px);
  box-shadow: 0 20px 60px rgba(107, 239, 139, 0.3);
}

body.light-mode .card:hover {
  box-shadow: 0 20px 60px rgba(107, 239, 139, 0.15);
}

.card:hover::before {
  transform: scaleX(1);
}

.card-icon { font-size: 40px; margin-bottom: 12px; display: block; color: var(--accent); }
.card h3 { margin: 12px 0 8px; }
.card p { font-size: 14px; margin-bottom: 0; }

/* FEATURE CARDS */
.feature-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px 24px;
  text-align: center;
  transition: all 0.3s;
  backdrop-filter: blur(10px);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.15);
}

.feature-card:hover {
  border-color: var(--accent);
  transform: translateY(-8px);
  box-shadow: 0 20px 50px rgba(107, 239, 139, 0.15);
}

.feature-icon { font-size: 48px; margin-bottom: 16px; display: block; }
.feature-card h3 { margin: 0 0 12px 0; }
.feature-card p { color: var(--text-secondary); margin-bottom: 0; }

/* COURSE CARDS */
.course-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
  transition: all 0.3s;
  backdrop-filter: blur(10px);
  display: flex;
  flex-direction: column;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.15);
  position: relative;
}

.course-badge {
  position: absolute;
  top: 12px;
  right: 12px;
  background: var(--accent);
  color: #071025;
  padding: 4px 10px;
  border-radius: 20px;
  font-size: 12px;
  font-weight: 700;
}

.course-card:hover { 
  border-color: var(--accent); 
  transform: translateY(-10px); 
  box-shadow: 0 20px 60px rgba(107, 239, 139, 0.25);
}

.course-icon { font-size: 36px; margin-bottom: 12px; }
.course-title { font-size: 20px; font-weight: 700; margin: 8px 0; color: var(--text); }
.course-meta { color: var(--text-secondary); font-size: 13px; margin: 8px 0 16px 0; }
.course-card p { flex-grow: 1; margin-bottom: 16px; }

/* COURSE LEARNING */
.learning-layout {
  display: grid;
  grid-template-columns: 320px minmax(0, 1fr);
  gap: 28px;
  align-items: start;
}

.learning-sidebar {
  position: sticky;
  top: 96px;
}

.learning-sidebar-card {
  max-height: calc(100vh - 120px);
  overflow: auto;
}

.learning-lesson-link {
  display: block;
  padding: 12px 14px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: rgba(107, 239, 139, 0.04);
  color: var(--text);
  transition: all 0.2s ease;
}

.learning-lesson-link:hover {
  border-color: var(--accent);
  background: rgba(107, 239, 139, 0.12);
  color: var(--text);
}

.learning-lesson-link.active {
  border-color: var(--accent);
  background: rgba(107, 239, 139, 0.14);
  box-shadow: 0 10px 30px rgba(107, 239, 139, 0.15);
}

.lesson-body h3,
.lesson-body h4 {
  color: var(--text);
  margin-top: 24px;
}

.lesson-body h3:first-child,
.lesson-body h4:first-child {
  margin-top: 0;
}

.lesson-body p,
.lesson-body li {
  color: var(--text-secondary);
  font-size: 15px;
  line-height: 1.9;
}

.lesson-body ul {
  margin: 16px 0 16px 22px;
}

.learning-nav {
  display: flex;
  gap: 16px;
  align-items: center;
  margin-top: 20px;
  flex-wrap: wrap;
}

/* TESTIMONIAL CARDS */
.testimonial-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  backdrop-filter: blur(10px);
  transition: all 0.3s;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.15);
}

.testimonial-card:hover { 
  border-color: var(--accent);
  transform: translateY(-8px);
  box-shadow: 0 20px 50px rgba(107, 239, 139, 0.15);
}

.testimonial-stars { color: var(--accent); font-size: 16px; margin-bottom: 12px; }
.testimonial-text { font-style: italic; color: var(--text-secondary); margin-bottom: 16px; }
.testimonial-author { display: flex; gap: 12px; align-items: center; }
.testimonial-avatar { width: 44px; height: 44px; border-radius: 50%; background: linear-gradient(135deg, var(--accent), var(--accent-dark)); display: flex; align-items: center; justify-content: center; color: #071025; font-weight: 700; font-size: 14px; }
.testimonial-name { font-weight: 600; color: var(--text); }
.testimonial-role { color: var(--text-secondary); font-size: 13px; }
.testimonial-submit-wrap { margin-top: 40px; }
.testimonial-submit-card { max-width: 900px; margin: 0 auto; }
.testimonial-form-row-tight { grid-template-columns: 220px 1fr; align-items: start; }
.testimonial-alert {
  margin-bottom: 24px;
  padding: 14px 16px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  font-size: 14px;
  font-weight: 600;
}
.testimonial-alert-success {
  background: rgba(107, 239, 139, 0.12);
  border-color: rgba(107, 239, 139, 0.35);
  color: var(--accent-light);
}
.testimonial-alert-error {
  background: rgba(255, 107, 107, 0.12);
  border-color: rgba(255, 107, 107, 0.35);
  color: #ffd3d3;
}
.testimonial-note {
  font-size: 13px;
  margin-bottom: 18px;
}
.testimonial-honeypot {
  position: absolute;
  left: -9999px;
  width: 1px;
  height: 1px;
  overflow: hidden;
}

/* FORMS */
.tool-section { max-width: 900px; margin: 0 auto 40px; }
.form-group { margin-bottom: 24px; }
.form-group label { display: block; margin-bottom: 8px; font-weight: 600; color: var(--text); font-size: 14px; }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }

input, textarea, select {
  width: 100%;
  padding: 12px 16px;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  font-family: inherit;
  font-size: 14px;
  transition: all 0.2s;
}

input:focus, textarea:focus, select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(107, 239, 139, 0.1);
  background: rgba(107, 239, 139, 0.02);
}

input::placeholder { color: var(--text-secondary); opacity: 0.7; }

/* FOOTER */
footer {
  background: var(--card-bg);
  border-top: 2px solid var(--accent);
  padding: 60px 0 24px;
  color: var(--text-secondary);
  transition: all 0.3s ease;
  backdrop-filter: blur(10px);
}

body.light-mode footer {
  background: rgba(248, 250, 252, 0.9);
  border-top: 2px solid var(--accent);
}

.footer-content { 
  display: grid; 
  grid-template-columns: repeat(4, 1fr); 
  gap: 40px; 
  margin-bottom: 40px;
}

.footer-section { padding: 0; }
.footer-section h4 { 
  color: var(--accent); 
  font-size: 16px; 
  margin-bottom: 16px;
  font-weight: 700;
}
.footer-section p {
  color: var(--text-secondary);
  line-height: 1.6;
  font-size: 14px;
}
.footer-section ul { list-style: none; }
.footer-section a { 
  color: var(--text-secondary); 
  font-size: 14px; 
  margin-bottom: 8px; 
  display: block;
  transition: all 0.2s;
}
.footer-section a:hover { 
  color: var(--accent);
  padding-left: 4px;
}

.footer-bottom { 
  border-top: 1px solid var(--border); 
  padding-top: 20px; 
  text-align: center; 
  color: var(--text-secondary); 
  font-size: 13px;
}

/* RESPONSIVE */
@media (max-width: 1024px) {
  section { padding: 60px 0; }
  .hero-icon { font-size: 100px; }
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .testimonials-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-content { grid-template-columns: repeat(2, 1fr); gap: 32px; }
}

@media (max-width: 768px) {
  h1 { font-size: 36px; }
  h2 { font-size: 28px; }
  section { padding: 48px 0; }
  .hero { padding: 80px 0; }
  .hero::before { width: 400px; height: 400px; }
  .nav-toggle { display: flex; }
  .nav-menu { 
    position: absolute;
    top: calc(100% + 10px);
    left: 16px;
    right: 16px;
    flex-direction: column;
    gap: 0;
    background: #0a0e27;
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 12px 20px;
    max-height: 0;
    overflow: hidden;
    opacity: 0;
    transform: translateY(-8px);
    transition: max-height 0.3s ease, opacity 0.25s ease, transform 0.25s ease;
    backdrop-filter: blur(10px);
    box-shadow: 0 16px 40px rgba(0, 0, 0, 0.28);
    z-index: 1001;
  }
  body.light-mode .nav-menu {
    background: #ffffff;
  }
  .nav-menu.active {
    max-height: 320px;
    opacity: 1;
    transform: translateY(0);
  }
  .nav-menu li {
    width: 100%;
    padding: 12px 0;
    border-bottom: 1px solid rgba(107, 239, 139, 0.1);
  }
  .nav-menu li:last-child {
    border-bottom: none;
  }
  .nav-menu a { 
    padding: 0; 
    display: block;
    padding-left: 0 !important;
  }
  .learning-layout {
    grid-template-columns: 1fr;
  }
  .learning-sidebar {
    position: static;
  }
  .learning-sidebar-card {
    max-height: none;
  }
  .navbar {
    position: relative;
  }
  body.menu-open {
    overflow: hidden;
  }
  .features-grid { grid-template-columns: 1fr; }
  .testimonials-grid { grid-template-columns: 1fr; }
  .courses-grid { grid-template-columns: 1fr; }
  .form-row { grid-template-columns: 1fr; }
  .testimonial-form-row-tight { grid-template-columns: 1fr; }
  .hero-ctas { flex-direction: column; }
  .btn { width: 100%; justify-content: center; }
  .footer-content { grid-template-columns: 1fr; gap: 24px; }
}

@media (max-width: 480px) {
  .container { padding: 0 16px; }
  h1 { font-size: 28px; }
  h2 { font-size: 22px; }
  h3 { font-size: 20px; }
  section { padding: 40px 0; }
  .hero { padding: 60px 0; }
  .nav-brand { font-size: 16px; }
  .nav-toggle { display: flex; }
  .feature-card { padding: 20px 16px; }
  .card { padding: 20px; }
}