/* ============================================
   CSS Variables & Reset
   ============================================ */

:root {
  /* Colors */
  --color-bg: #ffffff;
  --color-bg-light: #f8faff;
  --color-primary: #4a90e2;
  --color-primary-dark: #1e40af;
  --color-primary-light: #007bff;
  --color-accent: #dbeafe;
  --color-text: #1e293b;
  --color-text-light: #64748b;
  --color-white: #ffffff;

  /* Typography */
  --font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI",
    system-ui, sans-serif;
  --font-weight-light: 300;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  --spacing-2xl: 4rem;

  /* Transitions */
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;
  --transition-slow: 0.5s ease;

  /* Shadows */
  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 24px rgba(74, 144, 226, 0.15);
  --shadow-glow: 0 0 20px rgba(74, 144, 226, 0.4);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 100px;
  font-size: 16px;
}

body {
  font-family: var(--font-family);
  font-weight: var(--font-weight-normal);
  color: var(--color-text);
  background-color: var(--color-bg);
  line-height: 1.6;
  overflow-x: hidden;
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

/* ============================================
   Preloader
   ============================================ */

.preloader {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--color-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  transition: opacity var(--transition-slow), visibility var(--transition-slow);
}

.preloader.hidden {
  opacity: 0;
  visibility: hidden;
}

.preloader__spinner {
  width: 50px;
  height: 50px;
  border: 4px solid var(--color-accent);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

/* ============================================
   Header
   ============================================ */

.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-sm);
  z-index: 1000;
  transition: box-shadow var(--transition-normal);
}

.header__content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-sm) 0;
  gap: var(--spacing-md);
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  text-decoration: none;
  color: var(--color-text);
  font-weight: var(--font-weight-bold);
  font-size: 1.25rem;
}

.logo__icon {
  width: 32px;
  height: 32px;
  color: var(--color-primary);
  animation: knotRotate 20s linear infinite;
}

.logo__knot {
  stroke-dasharray: 100;
  stroke-dashoffset: 100;
  animation: knotDraw 3s ease-in-out infinite;
}

.logo__center {
  animation: pulse 2s ease-in-out infinite;
}

@keyframes knotRotate {
  0%,
  100% {
    transform: rotate(0deg);
  }
  50% {
    transform: rotate(180deg);
  }
}

@keyframes knotDraw {
  0%,
  100% {
    stroke-dashoffset: 100;
    opacity: 0.5;
  }
  50% {
    stroke-dashoffset: 0;
    opacity: 1;
  }
}

@keyframes pulse {
  0%,
  100% {
    opacity: 1;
    transform: scale(1);
  }
  50% {
    opacity: 0.7;
    transform: scale(1.1);
  }
}

.nav {
  display: flex;
  gap: var(--spacing-lg);
}

.nav__link {
  color: var(--color-text);
  text-decoration: none;
  font-weight: var(--font-weight-medium);
  transition: color var(--transition-fast);
  position: relative;
}

.nav__link::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-primary);
  transition: width var(--transition-normal);
}

.nav__link:hover {
  color: var(--color-primary);
}

.nav__link:hover::after {
  width: 100%;
}

/* ============================================
   Buttons
   ============================================ */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-sm) var(--spacing-lg);
  font-family: var(--font-family);
  font-weight: var(--font-weight-semibold);
  font-size: 1rem;
  text-decoration: none;
  border: none;
  border-radius: 12px;
  cursor: pointer;
  transition: all var(--transition-normal);
  white-space: nowrap;
}

.btn--primary {
  background: linear-gradient(
    135deg,
    var(--color-primary) 0%,
    var(--color-primary-light) 50%,
    var(--color-primary-dark) 100%
  );
  color: var(--color-white);
  box-shadow: var(--shadow-md);
}

.btn--primary:hover {
  transform: scale(1.05);
  box-shadow: var(--shadow-glow);
}

.btn--small {
  padding: var(--spacing-xs) var(--spacing-md);
  font-size: 0.875rem;
}

.btn--large {
  padding: var(--spacing-md) var(--spacing-xl);
  font-size: 1.125rem;
}

/* ============================================
   Hero Section
   ============================================ */

.hero {
  position: relative;
  min-height: 80vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding-top: 80px;
  overflow: hidden;
  background: linear-gradient(
    135deg,
    var(--color-bg-light) 0%,
    var(--color-white) 100%
  );
}

.hero__canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
}

.hero__overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: radial-gradient(
    circle at 50% 50%,
    rgba(219, 234, 254, 0.3) 0%,
    transparent 70%
  );
  z-index: 2;
  pointer-events: none;
}

.hero__content {
  position: relative;
  z-index: 3;
  text-align: center;
  max-width: 800px;
  margin: 0 auto;
  animation: fadeInUp 1s ease-out;
}

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

.hero__title {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: var(--font-weight-bold);
  color: var(--color-text);
  margin-bottom: var(--spacing-md);
  line-height: 1.2;
}

.hero__subtitle {
  font-size: clamp(1rem, 2.5vw, 1.25rem);
  color: var(--color-text-light);
  margin-bottom: var(--spacing-xl);
  font-weight: var(--font-weight-normal);
}

.hero__cta {
  margin-bottom: var(--spacing-xl);
}

.hero__features {
  display: flex;
  justify-content: center;
  gap: var(--spacing-xl);
  flex-wrap: wrap;
  margin-top: var(--spacing-xl);
}

.hero__feature {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  color: var(--color-text-light);
  font-size: 0.875rem;
  animation: floatUp 1s ease-out backwards;
}

.hero__feature:nth-child(1) {
  animation-delay: 0.2s;
}
.hero__feature:nth-child(2) {
  animation-delay: 0.4s;
}
.hero__feature:nth-child(3) {
  animation-delay: 0.6s;
}

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

.hero__feature-icon {
  width: 24px;
  height: 24px;
  color: var(--color-primary);
}

/* ============================================
   Features Section
   ============================================ */

.features {
  padding: var(--spacing-2xl) 0;
  background: var(--color-white);
}

.section__title {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: var(--font-weight-bold);
  text-align: center;
  margin-bottom: var(--spacing-2xl);
  color: var(--color-text);
}

.features__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-2xl);
}

.feature-card {
  background: var(--color-white);
  border: 2px solid var(--color-accent);
  border-radius: 16px;
  padding: var(--spacing-xl);
  text-align: center;
  transition: all var(--transition-normal);
  opacity: 0;
  transform: translateY(30px);
}

.feature-card.animate {
  opacity: 1;
  transform: translateY(0);
  animation: slideInUp 0.6s ease-out;
}

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

.feature-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-primary);
}

.feature-card__icon {
  width: 64px;
  height: 64px;
  margin: 0 auto var(--spacing-md);
  color: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-accent);
  border-radius: 16px;
  transition: all var(--transition-normal);
}

.feature-card:hover .feature-card__icon {
  transform: scale(1.1) rotate(5deg);
  background: linear-gradient(
    135deg,
    var(--color-primary) 0%,
    var(--color-primary-light) 100%
  );
  color: var(--color-white);
}

.feature-card__title {
  font-size: 1.25rem;
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-sm);
  color: var(--color-text);
}

.feature-card__text {
  color: var(--color-text-light);
  line-height: 1.6;
}

.features__trust {
  display: flex;
  justify-content: center;
  gap: var(--spacing-xl);
  flex-wrap: wrap;
  margin-top: var(--spacing-2xl);
}

.trust-badge {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--color-accent);
  border-radius: 12px;
  color: var(--color-text);
  font-weight: var(--font-weight-medium);
  opacity: 0;
  transform: scale(0.8);
  transition: all var(--transition-normal);
}

.trust-badge.animate {
  opacity: 1;
  transform: scale(1);
  animation: scaleIn 0.5s ease-out;
}

@keyframes scaleIn {
  from {
    opacity: 0;
    transform: scale(0.8);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

.trust-badge svg {
  color: var(--color-primary);
}

/* ============================================
   How to Buy Section
   ============================================ */

.how-to-buy {
  padding: var(--spacing-2xl) 0;
  background: var(--color-bg-light);
}

.steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-2xl);
}

.step {
  position: relative;
  background: var(--color-white);
  border-radius: 16px;
  padding: var(--spacing-xl);
  text-align: center;
  box-shadow: var(--shadow-md);
  transition: all var(--transition-normal);
  opacity: 0;
  transform: translateX(-30px);
}

.step.animate {
  opacity: 1;
  transform: translateX(0);
  animation: slideInLeft 0.6s ease-out;
}

@keyframes slideInLeft {
  from {
    opacity: 0;
    transform: translateX(-30px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

.step:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
}

.step__number {
  position: absolute;
  top: -20px;
  left: 50%;
  transform: translateX(-50%);
  width: 40px;
  height: 40px;
  background: linear-gradient(
    135deg,
    var(--color-primary) 0%,
    var(--color-primary-light) 100%
  );
  color: var(--color-white);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: var(--font-weight-bold);
  font-size: 1.25rem;
  box-shadow: var(--shadow-md);
}

.step__icon {
  width: 64px;
  height: 64px;
  margin: var(--spacing-md) auto;
  color: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
}

.step__title {
  font-size: 1.25rem;
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-sm);
  color: var(--color-text);
}

.step__text {
  color: var(--color-text-light);
  line-height: 1.6;
}

.how-to-buy__cta {
  text-align: center;
}

/* ============================================
   Support Section
   ============================================ */

.support {
  padding: var(--spacing-2xl) 0;
  background: var(--color-white);
  text-align: center;
}

.support__text {
  font-size: 1.125rem;
  color: var(--color-text-light);
  margin-bottom: var(--spacing-xl);
}

.support__links {
  display: flex;
  justify-content: center;
  gap: var(--spacing-lg);
  flex-wrap: wrap;
}

.support-link {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) var(--spacing-lg);
  background: var(--color-accent);
  border-radius: 12px;
  text-decoration: none;
  color: var(--color-text);
  font-weight: var(--font-weight-medium);
  transition: all var(--transition-normal);
  opacity: 0;
  transform: translateY(20px);
}

.support-link.animate {
  opacity: 1;
  transform: translateY(0);
  animation: fadeInUp 0.6s ease-out;
}

.support-link:hover {
  background: var(--color-primary);
  color: var(--color-white);
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.support-link svg {
  color: var(--color-primary);
  transition: color var(--transition-normal);
}

.support-link:hover svg {
  color: var(--color-white);
}

/* ============================================
   Footer
   ============================================ */

.footer {
  padding: var(--spacing-xl) 0;
  background: var(--color-text);
  color: var(--color-white);
}

.footer__content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-md);
  text-align: center;
}

.footer__text {
  color: rgba(255, 255, 255, 0.8);
  font-size: 0.875rem;
}

.footer .btn--primary {
  background: linear-gradient(
    135deg,
    var(--color-primary) 0%,
    var(--color-primary-light) 100%
  );
}

/* ============================================
   Responsive Design
   ============================================ */

@media (max-width: 1024px) {
  .container {
    padding: 0 var(--spacing-sm);
  }

  .features__grid {
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: var(--spacing-lg);
  }

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

@media (max-width: 768px) {
  .header {
    padding: 0;
  }

  .header__content {
    flex-wrap: wrap;
    padding: var(--spacing-xs) 0;
    min-height: auto;
  }

  .nav {
    order: 3;
    width: 100%;
    justify-content: center;
    gap: var(--spacing-md);
    padding-top: var(--spacing-xs);
  }

  .nav__link {
    font-size: 0.875rem;
  }

  .hero {
    min-height: 70vh;
    padding-top: 140px;
  }

  .hero__features {
    flex-direction: column;
    gap: var(--spacing-md);
  }

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

  .features__trust {
    flex-direction: column;
    align-items: center;
  }

  .support__links {
    flex-direction: column;
    align-items: center;
  }

  .footer__content {
    gap: var(--spacing-sm);
  }
}

@media (max-width: 480px) {
  html {
    font-size: 14px;
  }

  .logo {
    font-size: 1rem;
  }

  .logo__icon {
    width: 24px;
    height: 24px;
  }

  .btn--small {
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: 0.75rem;
  }

  .hero {
    min-height: 60vh;
    padding-top: 160px;
  }

  .header__content {
    padding: var(--spacing-xs) 0;
  }

  .logo {
    flex: 1;
  }

  .btn--small {
    flex-shrink: 0;
  }

  .feature-card,
  .step {
    padding: var(--spacing-md);
  }

  .section__title {
    margin-bottom: var(--spacing-xl);
  }
}

/* ============================================
   Utility Classes
   ============================================ */

.hidden {
  display: none !important;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}