/* ============================================
   CSS CUSTOM PROPERTIES
   ============================================ */
:root {
  --primary: #6366f1;
  --primary-dark: #4f46e5;
  --secondary: #8b5cf6;
  --accent: #06b6d4;
  --bg: #0f172a;
  --bg-light: #1e293b;
  --text: #f1f5f9;
  --text-muted: #94a3b8;
  --border: rgba(255, 255, 255, 0.1);
  --success: #10b981;
  --error: #ef4444;
  --radius: 12px;
  --gradient-primary: linear-gradient(135deg, var(--primary), var(--secondary));
  --gradient-brand: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 50%, var(--accent) 100%);
}

/* ============================================
   BASE STYLES
   ============================================ */
*, *::before, *::after {
  box-sizing: border-box;
}

* {
  margin: 0;
  padding: 0;
}

html {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  max-width: 100vw;
  overflow-x: hidden;
}

main {
  position: relative;
}

/* ============================================
   SCROLL PROGRESS
   ============================================ */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 0%;
  height: 3px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  z-index: 101;
  transition: width 0.1s ease-out;
}

/* ============================================
   LAYOUT
   ============================================ */
.container {
  max-width: 1200px;
  margin-inline: auto;
  padding-inline: 1.25rem;
}

/* ============================================
   NAVIGATION
   ============================================ */
nav {
  position: -webkit-sticky;
  position: sticky;
  top: 0;
  background: rgba(15, 23, 42, 0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding-block: 1rem;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  z-index: 100;
  will-change: position;
}

.nav-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  background-clip: text;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.nav-links {
  display: flex;
  gap: 2rem;
  align-items: center;
}

.nav-main,
.nav-settings {
  display: flex;
  gap: 2rem;
  align-items: center;
}

.nav-settings { gap: 1rem; }

.nav-links a {
  color: var(--text-muted);
  text-decoration: none;
  transition: color 0.3s;
  white-space: nowrap;
}

.nav-links a:hover {
  color: var(--text);
}

/* ============================================
   LANGUAGE SWITCH
   ============================================ */
.lang-switch {
  background: var(--bg-light);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 0.25rem;
  display: flex;
  gap: 0.25rem;
}

.lang-switch button {
  background: none;
  border: none;
  color: var(--text-muted);
  padding: 0.25rem 0.75rem;
  border-radius: 16px;
  cursor: pointer;
  transition: all 0.3s;
  font-size: 0.875rem;
}

.lang-switch button.active {
  background: var(--primary);
  color: white;
}

/* ============================================
   MOBILE MENU
   ============================================ */
.mobile-menu-btn {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

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

.mobile-menu-btn.active span:nth-child(1) {
  transform: rotate(45deg) translate(7px, 7px);
}

.mobile-menu-btn.active span:nth-child(2) {
  opacity: 0;
}

.mobile-menu-btn.active span:nth-child(3) {
  transform: rotate(-45deg) translate(7px, -7px);
}

/* ============================================
   THEME PICKER
   ============================================ */
.theme-picker {
  position: relative;
}

.theme-btn {
  background: var(--bg-light);
  border: 1px solid var(--border);
  color: var(--text-muted);
  cursor: pointer;
  padding: 8px 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s;
  border-radius: 8px;
}

.theme-btn:hover {
  color: var(--text);
  border-color: var(--primary);
  background: rgba(99, 102, 241, 0.1);
}

.theme-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  background: var(--bg-light);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 12px;
  display: none;
  flex-direction: column;
  gap: 10px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
  backdrop-filter: blur(12px);
  min-width: 200px;
  z-index: 1000;
}

.theme-menu.active {
  display: flex;
}

.theme-label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-muted);
  font-weight: 600;
  padding-inline: 4px;
}

.theme-options {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
}

.theme-options button {
  width: 44px;
  height: 44px;
  border: 2px solid transparent;
  border-radius: 50%;
  cursor: pointer;
  transition: all 0.3s;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}

.theme-options button:hover {
  transform: scale(1.1);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

.theme-options button.active {
  border-color: var(--text);
  transform: scale(1.05);
}

.theme-check {
  opacity: 0;
  transition: opacity 0.2s;
  stroke: white;
  stroke-width: 2;
  fill: none;
  filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.3));
}

.theme-options button.active .theme-check {
  opacity: 1;
}

/* ============================================
   TYPOGRAPHY
   ============================================ */
h1 {
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  font-weight: 800;
  margin-bottom: 1rem;
  background: var(--gradient-brand);
  background-clip: text;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  line-height: 1.1;
}

.section-title {
  font-size: clamp(2rem, 4vw, 2.75rem);
  font-weight: 700;
  text-align: center;
  margin-bottom: 1rem;
}

.section-subtitle {
  text-align: center;
  color: var(--text-muted);
  margin-bottom: 3rem;
  font-size: 1.125rem;
}

.subtitle {
  font-size: clamp(1.25rem, 3vw, 1.75rem);
  font-weight: 600;
  margin-bottom: 1rem;
}

.description {
  font-size: 1.125rem;
  color: var(--text-muted);
  max-width: 600px;
  margin-inline: auto;
  margin-bottom: 2.5rem;
}

/* ============================================
   BUTTONS
   ============================================ */
.btn {
  padding: 0.875rem 2rem;
  border-radius: var(--radius);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s;
  text-decoration: none;
  display: inline-block;
  border: none;
}

.btn-primary {
  background: var(--gradient-primary);
  color: white;
  box-shadow: 0 4px 20px rgba(99, 102, 241, 0.4);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 30px rgba(99, 102, 241, 0.5);
}

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

.btn-secondary:hover {
  border-color: var(--primary);
  background: rgba(99, 102, 241, 0.1);
}

.btn-group {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

/* ============================================
   SECTIONS
   ============================================ */
section {
  padding-block: 4rem;
}

/* Hero Section */
.hero {
  padding: 6rem 0 4rem;
  text-align: center;
  position: relative;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: 50%;
  transform: translateX(-50%);
  width: 100%;
  height: 100%;
  background: radial-gradient(circle, rgba(99, 102, 241, 0.15), transparent 70%);
  pointer-events: none;
}

.badge {
  display: inline-block;
  background: rgba(99, 102, 241, 0.1);
  border: 1px solid rgba(99, 102, 241, 0.3);
  padding: 0.5rem 1rem;
  border-radius: 20px;
  font-size: 0.875rem;
  color: var(--accent);
  margin-bottom: 2rem;
}

/* Problem/Solution Section */
.problem-solution {
  background: linear-gradient(180deg, transparent, var(--bg-light) 50%, transparent);
}

.problem-box,
.solution-box {
  border-radius: var(--radius);
  padding: 2.5rem;
  text-align: center;
}

.problem-box {
  background: rgba(239, 68, 68, 0.05);
  border: 2px solid rgba(239, 68, 68, 0.2);
  margin-bottom: 3rem;
}

.solution-box {
  background: rgba(16, 185, 129, 0.05);
  border: 2px solid rgba(16, 185, 129, 0.2);
}

.stat {
  font-size: 2.5rem;
  font-weight: 800;
  margin-bottom: 1rem;
}

.stat-highlight {
  color: var(--error);
}

.guarantee {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--success);
  margin-top: 1rem;
}

/* ============================================
   CARDS & GRIDS
   ============================================ */
.steps,
.features-grid,
.pricing-grid {
  display: grid;
  gap: 2rem;
  margin-top: 3rem;
}

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

.features-grid {
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.5rem;
}

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

/* Step Cards */
.step,
.feature,
.price-card {
  background: var(--bg-light);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  transition: all 0.3s;
}

.step {
  position: relative;
}

.step:hover,
.price-card:hover {
  transform: translateY(-5px);
  border-color: var(--primary);
  box-shadow: 0 10px 40px rgba(99, 102, 241, 0.2);
}

.feature {
  padding: 1.75rem;
}

.feature:hover {
  border-color: var(--accent);
  box-shadow: 0 8px 30px rgba(6, 182, 212, 0.15);
}

.step-number {
  position: absolute;
  top: -15px;
  left: 20px;
  width: 40px;
  height: 40px;
  background: var(--gradient-primary);
  border-radius: 50%;
  display: grid;
  place-items: center;
  font-weight: 700;
  font-size: 1.25rem;
}

.step h3 {
  margin: 1rem 0 0.75rem;
  font-size: 1.25rem;
}

.step p,
.feature p {
  color: var(--text-muted);
}

.feature h3 {
  font-size: 1.125rem;
  margin-bottom: 0.5rem;
}

.feature p {
  font-size: 0.95rem;
}

/* Price Cards */
.price-card {
  border-width: 2px;
  position: relative;
}

.price-card.popular {
  border-color: var(--primary);
  box-shadow: 0 0 40px rgba(99, 102, 241, 0.3);
}

.popular-badge {
  position: absolute;
  top: -12px;
  right: 20px;
  background: var(--gradient-primary);
  color: white;
  padding: 0.35rem 0.875rem;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 700;
}

.price-card h3 {
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
}

.price {
  font-size: 3rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  background-clip: text;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin: 1rem 0;
}

.price-desc {
  color: var(--text-muted);
  margin-bottom: 1.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border);
}

.price-card ul {
  list-style: none;
  margin-bottom: 2rem;
}

.price-card li {
  padding: 0.5rem 0;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.price-card li::before {
  content: '✓';
  color: var(--success);
  font-weight: 700;
}

/* ============================================
   CTA & CONTACT FORM
   ============================================ */
.cta-section {
  text-align: center;
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.1), rgba(139, 92, 246, 0.1));
  border-radius: var(--radius);
  padding: 4rem 2rem;
  margin: 4rem 0;
}

.contact-form {
  max-width: 500px;
  margin: 3rem auto 0;
  background: var(--bg-light);
  padding: 2.5rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.form-group {
  margin-bottom: 1.5rem;
}

.form-group label {
  display: block;
  margin-bottom: 0.5rem;
  color: var(--text-muted);
  font-size: 0.95rem;
}

.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 0.875rem;
  background: var(--bg);
  border: 2px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  font-size: 1rem;
  font-family: inherit;
  transition: all 0.3s;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

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

.submit-btn {
  width: 100%;
  padding: 1rem;
  background: var(--gradient-primary);
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s;
}

.submit-btn:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: 0 6px 30px rgba(99, 102, 241, 0.4);
}

.submit-btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.form-message {
  padding: 1rem;
  border-radius: 8px;
  margin-bottom: 1rem;
  text-align: center;
  font-weight: 500;
  display: none;
}

.form-message.success,
.form-message.error {
  display: block;
}

.form-message.success {
  background: rgba(16, 185, 129, 0.1);
  border: 1px solid var(--success);
  color: var(--success);
}

.form-message.error {
  background: rgba(239, 68, 68, 0.1);
  border: 1px solid var(--error);
  color: var(--error);
}

/* ============================================
   FOOTER
   ============================================ */
footer {
  border-top: 1px solid var(--border);
  padding: 3rem 0 2rem;
  text-align: center;
  color: var(--text-muted);
}

.footer-content {
  max-width: 800px;
  margin-inline: auto;
}

.footer-logo {
  font-size: 1.75rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  background-clip: text;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 0.5rem;
}

.footer-tagline {
  font-size: 1rem;
  margin-bottom: 1.5rem;
}

.footer-bottom {
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  font-size: 0.875rem;
}

/* ============================================
   RESPONSIVE DESIGN
   ============================================ */
@media (min-width: 769px) {
  .nav-main {
    gap: 1.5rem;
  }

  .theme-picker,
  .lang-switch {
    flex-shrink: 0;
  }
}

@media (max-width: 768px) {
  nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    width: 100%;
  }

  main {
    padding-top: 65px;
  }

  .mobile-menu-btn {
    display: flex;
  }

  .nav-links {
    position: fixed;
    top: 65px;
    right: -100%;
    width: min(300px, 80vw);
    height: calc(100vh - 65px);
    background: rgba(30, 41, 59, 0.98);
    backdrop-filter: blur(12px);
    border-left: 1px solid var(--border);
    flex-direction: column;
    gap: 0;
    padding: 0;
    transition: right 0.3s;
    align-items: stretch;
    overflow-y: auto;
    z-index: 50;
  }

  .nav-links.active {
    right: 0;
  }

  .nav-main {
    flex-direction: column;
    gap: 0;
    padding: 1rem 0;
    border-bottom: 1px solid var(--border);
  }

  .nav-links a {
    padding: 1rem 1.5rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    font-size: 1rem;
  }

  .nav-settings {
    flex-direction: column;
    gap: 0;
    padding: 1.5rem;
  }

  .theme-picker {
    width: 100%;
    margin-bottom: 1.5rem;
  }

  .theme-btn {
    width: 100%;
    justify-content: space-between;
    padding: 12px 16px;
  }

  .theme-btn::after {
    content: 'Theme';
    font-size: 0.95rem;
    color: var(--text);
  }

  .theme-menu {
    position: static;
    margin-top: 12px;
    width: 100%;
    box-shadow: none;
  }

  .lang-switch {
    width: 100%;
    justify-content: center;
    padding: 0.5rem;
  }

  .hero {
    padding: 4rem 0 3rem;
  }

  section {
    padding-block: 3rem;
  }

  .btn-group {
    flex-direction: column;
    align-items: stretch;
  }

  .steps,
  .features-grid,
  .pricing-grid {
    grid-template-columns: 1fr;
  }

  .contact-form {
    padding: 1.5rem;
  }
}