/* Modern CSS Reset and Base Styles */
:root {
  /* Color Palette */
  --primary-color: #007bff;
  --primary-hover: #0056b3;
  --primary-light: #e3f2fd;
  --secondary-color: #6c757d;
  --success-color: #28a745;
  --warning-color: #ffc107;
  --danger-color: #dc3545;
  --light-color: #f8f9fa;
  --dark-color: #343a40;
  
  /* Neutral Colors */
  --white: #ffffff;
  --black: #000000;
  --gray-100: #f8f9fa;
  --gray-200: #e9ecef;
  --gray-300: #dee2e6;
  --gray-400: #ced4da;
  --gray-500: #adb5bd;
  --gray-600: #6c757d;
  --gray-700: #495057;
  --gray-800: #343a40;
  --gray-900: #212529;
  
  /* Typography */
  --font-family-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --font-family-mono: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, 'Courier New', monospace;
  
  /* Font Sizes */
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --font-size-4xl: 2.25rem;
  --font-size-5xl: 3rem;
  
  /* Spacing */
  --spacing-1: 0.25rem;
  --spacing-2: 0.5rem;
  --spacing-3: 0.75rem;
  --spacing-4: 1rem;
  --spacing-5: 1.25rem;
  --spacing-6: 1.5rem;
  --spacing-8: 2rem;
  --spacing-10: 2.5rem;
  --spacing-12: 3rem;
  --spacing-16: 4rem;
  --spacing-20: 5rem;
  
  /* Border Radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.375rem;
  --radius-lg: 0.5rem;
  --radius-xl: 0.75rem;
  --radius-2xl: 1rem;
  --radius-full: 9999px;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
  
  /* Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-normal: 250ms ease-in-out;
  --transition-slow: 350ms ease-in-out;
  
  /* Z-index */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-popover: 1060;
  --z-tooltip: 1070;
}

/* CSS Reset */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  line-height: 1.5;
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-family-sans);
  font-size: var(--font-size-base);
  line-height: 1.6;
  color: var(--gray-800);
  background-color: var(--gray-100);
  margin: 0;
  padding: 0;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  overflow-x: hidden;
}

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

/* Focus Styles */
*:focus-visible {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

/* Main Container */
.container {
  position: relative;
  width: 100%;
  max-width: 1200px;
  height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Landing Page */
.landing-page {
  position: relative;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
}

.background-video {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: 1;
}

/* Video Overlay */
.background-video::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(135deg, rgba(0, 123, 255, 0.8) 0%, rgba(0, 86, 179, 0.6) 100%);
  z-index: 1;
}

/* Content */
.content {
  position: relative;
  z-index: 2;
  text-align: center;
  color: var(--white);
  padding: var(--spacing-8);
  max-width: 600px;
  animation: fadeInUp 0.8s ease-out;
}

.content h1 {
  font-size: clamp(var(--font-size-3xl), 5vw, var(--font-size-5xl));
  font-weight: 700;
  margin-bottom: var(--spacing-4);
  line-height: 1.2;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

.content p {
  font-size: var(--font-size-lg);
  margin-bottom: var(--spacing-8);
  opacity: 0.95;
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
}

/* CTA Button */
.cta-button {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-2);
  padding: var(--spacing-4) var(--spacing-8);
  font-size: var(--font-size-lg);
  font-weight: 600;
  background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-hover) 100%);
  color: var(--white);
  border: none;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-lg);
  text-decoration: none;
  position: relative;
  overflow: hidden;
}

.cta-button::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
  transition: left var(--transition-slow);
}

.cta-button:hover::before {
  left: 100%;
}

.cta-button:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-xl);
  background: linear-gradient(135deg, var(--primary-hover) 0%, var(--primary-color) 100%);
}

.cta-button:active {
  transform: translateY(0);
}

.button-icon {
  font-size: var(--font-size-xl);
  animation: pulse 2s infinite;
}

/* Modal Styles */
.modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
  z-index: var(--z-modal);
  display: none;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-4);
  animation: fadeIn var(--transition-normal);
  border: none;
  margin: 0;
  padding: 0;
}

.modal[open] {
  display: flex;
}

/* Fallback for browsers that don't support dialog */
.modal.show {
  display: flex !important;
}

.modal-content {
  background: var(--white);
  border-radius: var(--radius-2xl);
  width: 100%;
  max-width: 600px;
  max-height: 90vh;
  overflow: hidden;
  box-shadow: var(--shadow-xl);
  animation: slideInUp var(--transition-normal);
  position: relative;
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-6);
  border-bottom: 1px solid var(--gray-200);
  background: var(--gray-50);
}

.modal-title {
  font-size: var(--font-size-xl);
  font-weight: 600;
  color: var(--gray-900);
  margin: 0;
}

.close-button {
  background: none;
  border: none;
  font-size: var(--font-size-2xl);
  color: var(--gray-500);
  cursor: pointer;
  padding: var(--spacing-2);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  line-height: 1;
}

.close-button:hover {
  color: var(--gray-700);
  background: var(--gray-100);
}

.modal-body {
  padding: var(--spacing-6);
  overflow-y: auto;
  max-height: calc(90vh - 80px);
}

/* Modal Steps */
.modal-step {
  display: none;
  animation: fadeIn var(--transition-normal);
}

.modal-step.active {
  display: block;
}

/* Donation Form */
.donation-form {
  width: 100%;
}

.amount-selection {
  border: none;
  padding: 0;
  margin: 0 0 var(--spacing-6) 0;
}

.amount-options {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: var(--spacing-3);
  margin-bottom: var(--spacing-6);
}

.amount-option {
  position: relative;
  cursor: pointer;
}

.amount-option input[type="radio"] {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.amount-label {
  display: block;
  padding: var(--spacing-4);
  text-align: center;
  background: var(--gray-100);
  border: 2px solid var(--gray-200);
  border-radius: var(--radius-lg);
  font-weight: 600;
  color: var(--gray-700);
  transition: all var(--transition-fast);
}

.amount-option input[type="radio"]:checked + .amount-label {
  background: var(--primary-light);
  border-color: var(--primary-color);
  color: var(--primary-color);
  transform: scale(1.05);
}

.amount-option:hover .amount-label {
  border-color: var(--primary-color);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.custom-amount-container {
  margin-top: var(--spacing-4);
}

.custom-amount-input {
  width: 100%;
  padding: var(--spacing-4);
  border: 2px solid var(--gray-200);
  border-radius: var(--radius-lg);
  font-size: var(--font-size-lg);
  font-weight: 600;
  text-align: center;
  transition: all var(--transition-fast);
  display: none;
}

.custom-amount-input:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.1);
}

.custom-amount-input.show {
  display: block;
  animation: slideDown var(--transition-normal);
}

/* Crypto Options */
.crypto-options {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-4);
  margin-bottom: var(--spacing-6);
}

.crypto-button {
  display: flex;
  align-items: center;
  gap: var(--spacing-3);
  padding: var(--spacing-4);
  background: var(--white);
  border: 2px solid var(--gray-200);
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: all var(--transition-fast);
  text-align: left;
  width: 100%;
}

.crypto-button:hover {
  border-color: var(--primary-color);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.crypto-button:active {
  transform: translateY(0);
}

.crypto-button img {
  width: 32px;
  height: 32px;
  flex-shrink: 0;
}

.crypto-info {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-1);
}

.crypto-name {
  font-weight: 600;
  color: var(--gray-900);
}

.crypto-symbol {
  font-size: var(--font-size-sm);
  color: var(--gray-600);
  font-family: var(--font-family-mono);
}

/* Selected Details */
.selected-details {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-6);
  margin-bottom: var(--spacing-6);
}

.donation-summary {
  background: var(--gray-50);
  padding: var(--spacing-6);
  border-radius: var(--radius-lg);
  border: 1px solid var(--gray-200);
}

.crypto-title {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--primary-color);
  margin-bottom: var(--spacing-2);
}

.amount-display {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--gray-700);
  margin-bottom: var(--spacing-4);
}

.address-container {
  margin-top: var(--spacing-4);
}

.address-label {
  display: block;
  font-weight: 600;
  color: var(--gray-700);
  margin-bottom: var(--spacing-2);
}

.address-input-group {
  display: flex;
  gap: var(--spacing-2);
}

.address-input {
  flex: 1;
  padding: var(--spacing-3);
  border: 2px solid var(--gray-200);
  border-radius: var(--radius-md);
  font-family: var(--font-family-mono);
  font-size: var(--font-size-sm);
  background: var(--white);
  color: var(--gray-700);
}

.copy-button {
  display: flex;
  align-items: center;
  gap: var(--spacing-2);
  padding: var(--spacing-3) var(--spacing-4);
  background: var(--primary-color);
  color: var(--white);
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  font-weight: 600;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.copy-button:hover {
  background: var(--primary-hover);
  transform: translateY(-1px);
}

.copy-button:active {
  transform: translateY(0);
}

.qr-container {
  text-align: center;
  background: var(--white);
  padding: var(--spacing-6);
  border-radius: var(--radius-lg);
  border: 1px solid var(--gray-200);
}

.qr-container h4 {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--gray-700);
  margin-bottom: var(--spacing-4);
}

.qr-code {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 200px;
  background: var(--white);
  border-radius: var(--radius-md);
}

/* Modal Actions */
.modal-actions {
  display: flex;
  gap: var(--spacing-3);
  justify-content: flex-end;
  padding-top: var(--spacing-4);
  border-top: 1px solid var(--gray-200);
}

/* Button Styles */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-2);
  padding: var(--spacing-3) var(--spacing-6);
  font-size: var(--font-size-base);
  font-weight: 600;
  border: none;
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
  position: relative;
  overflow: hidden;
}

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

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn-secondary {
  background: var(--gray-100);
  color: var(--gray-700);
  border: 1px solid var(--gray-300);
}

.btn-secondary:hover {
  background: var(--gray-200);
  transform: translateY(-1px);
}

/* Animations */
@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

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

@keyframes slideInUp {
  from {
    opacity: 0;
    transform: translateY(50px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

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

/* Responsive Design */
@media (min-width: 640px) {
  .container {
    margin: var(--spacing-4);
    height: calc(100vh - 2rem);
  }
  
  .landing-page {
    border-radius: var(--radius-2xl);
  }
  
  .content {
    padding: var(--spacing-12);
  }
  
  .amount-options {
    grid-template-columns: repeat(3, 1fr);
  }
  
  .crypto-options {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .selected-details {
    grid-template-columns: 1fr 1fr;
    align-items: start;
  }
}

@media (min-width: 768px) {
  .modal-content {
    max-width: 700px;
  }
  
  .amount-options {
    grid-template-columns: repeat(5, 1fr);
  }
  
  .crypto-options {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .content h1 {
    font-size: var(--font-size-5xl);
  }
  
  .content p {
    font-size: var(--font-size-xl);
  }
}

/* High Contrast Mode */
@media (prefers-contrast: high) {
  :root {
    --primary-color: #0000ff;
    --primary-hover: #000080;
    --gray-200: #000000;
    --gray-500: #000000;
  }
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  
  .cta-button::before {
    display: none;
  }
}

/* Print Styles */
@media print {
  .background-video,
  .modal {
    display: none !important;
  }
  
  .content {
    color: var(--black);
    text-shadow: none;
  }
}