:root {
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --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;
  --font-size-6xl: 3.75rem;
  
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  
  --color-black: #000000;
  --color-gray-900: #111827;
  --color-gray-800: #1f2937;
  --color-gray-700: #374151;
  --color-gray-600: #4b5563;
  --color-gray-500: #6b7280;
  --color-gray-400: #9ca3af;
  --color-gray-300: #d1d5db;
  --color-gray-200: #e5e7eb;
  --color-gray-100: #f3f4f6;
  --color-gray-50: #f9fafb;
  --color-white: #ffffff;
  
  --color-primary: var(--color-black);
  --color-secondary: var(--color-gray-600);
  --color-tertiary: var(--color-gray-400);
  --color-background: var(--color-white);
  --color-surface: var(--color-gray-50);
  --color-border: var(--color-gray-200);
  --color-border-focus: var(--color-gray-400);
  --color-text-primary: var(--color-black);
  --color-text-secondary: var(--color-gray-600);
  --color-text-tertiary: var(--color-gray-500);
  
  --color-error: #dc2626;
  --color-error-light: #fef2f2;
  --color-error-border: #fecaca;
  
  --color-success: #059669;
  --color-success-light: #ecfdf5;
  --color-success-border: #a7f3d0;
  
  --spacing-0: 0;
  --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;
  --spacing-24: 6rem;
  
  --radius-sm: 0.125rem;
  --radius-base: 0.25rem;
  --radius-md: 0.375rem;
  --radius-lg: 0.5rem;
  --radius-xl: 0.75rem;
  --radius-2xl: 1rem;
  --radius-full: 9999px;
  
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-base: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
  --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);
  
  --transition-fast: 150ms ease-in-out;
  --transition-base: 250ms ease-in-out;
  --transition-slow: 350ms ease-in-out;
  
  --container-max-width: 42rem;
  --header-height: 5rem;
  --footer-height: 4rem;
}

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

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

body {
  font-family: var(--font-family);
  font-weight: var(--font-weight-normal);
  color: var(--color-text-primary);
  background-color: var(--color-background);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.container {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-4);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.header {
  padding: var(--spacing-8) 0 var(--spacing-6);
  text-align: center;
}

.main {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-4) 0;
}

.footer {
  padding: var(--spacing-6) 0;
  text-align: center;
  border-top: 1px solid var(--color-border);
  margin-top: auto;
}

.home-page {
  width: 100%;
  max-width: 100%;
}

.url-form-container {
  width: 100%;
}

.url-form {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-6);
  align-items: center;
}

.input-group {
  width: 100%;
  max-width: 32rem;
}

.url-input {
  width: 100%;
  padding: var(--spacing-6);
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-medium);
  font-family: var(--font-family);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-lg);
  background-color: var(--color-white);
  color: var(--color-text-primary);
  transition: all var(--transition-base);
  outline: none;
}

.url-input:focus {
  border-color: var(--color-border-focus);
  box-shadow: 0 0 0 3px rgb(0 0 0 / 0.05);
}

.url-input::placeholder {
  color: var(--color-text-tertiary);
  font-weight: var(--font-weight-normal);
}

.submit-button {
  padding: var(--spacing-6) var(--spacing-12);
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-semibold);
  font-family: var(--font-family);
  background-color: var(--color-primary);
  color: var(--color-white);
  border: none;
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: all var(--transition-base);
  outline: none;
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 8rem;
  min-height: 4rem;
}

.submit-button:hover {
  background-color: var(--color-gray-800);
  transform: translateY(-1px);
  box-shadow: var(--shadow-lg);
}

.submit-button:active {
  transform: translateY(0);
  box-shadow: var(--shadow-base);
}

.submit-button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

.result-page {
  width: 100%;
  max-width: 100%;
}

.result-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-8);
  text-align: center;
}

.short-url-display {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-4);
  width: 100%;
  max-width: 32rem;
}

.short-url {
  font-size: var(--font-size-3xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
  padding: var(--spacing-6);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  word-break: break-all;
  cursor: pointer;
  transition: all var(--transition-base);
  user-select: all;
}

.short-url:hover {
  background-color: var(--color-gray-100);
  border-color: var(--color-border-focus);
}

.qr-code-container {
  display: flex;
  justify-content: center;
  padding: var(--spacing-4);
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
}

.qr-code {
  max-width: 200px;
  height: auto;
  border-radius: var(--radius-base);
}

.action-buttons {
  display: flex;
  gap: var(--spacing-4);
  flex-wrap: wrap;
  justify-content: center;
}

.action-button {
  padding: var(--spacing-4) var(--spacing-6);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  font-family: var(--font-family);
  background-color: var(--color-white);
  color: var(--color-text-primary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
  outline: none;
}

.action-button:hover {
  background-color: var(--color-gray-50);
  border-color: var(--color-border-focus);
  text-decoration: none;
}

.new-url-button {
  background-color: var(--color-primary);
  color: var(--color-white);
  border-color: var(--color-primary);
}

.new-url-button:hover {
  background-color: var(--color-gray-800);
  border-color: var(--color-gray-800);
}

.loading-page {
  width: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
}

.loading-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-4);
}

.loading-spinner {
  font-size: var(--font-size-4xl);
  animation: spin 1s linear infinite;
}

.loading-text {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  font-weight: var(--font-weight-medium);
}

@keyframes spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

.error-page {
  width: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
}

.error-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-6);
  text-align: center;
  max-width: 28rem;
}

.error-icon {
  font-size: var(--font-size-5xl);
}

.error-message {
  font-size: var(--font-size-lg);
  color: var(--color-error);
  font-weight: var(--font-weight-medium);
}

.retry-button {
  background-color: var(--color-error);
  color: var(--color-white);
  border-color: var(--color-error);
}

.retry-button:hover {
  background-color: #b91c1c;
  border-color: #b91c1c;
}

.footer-content {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-4);
}

.copyright {
  font-size: var(--font-size-sm);
  color: var(--color-text-tertiary);
  margin: 0;
}

.copyright a {
  color: var(--color-text-tertiary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.copyright a:hover {
  color: var(--color-text-secondary);
  text-decoration: underline;
}

.notification-container {
  position: fixed;
  top: var(--spacing-4);
  right: var(--spacing-4);
  z-index: 1000;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-2);
  pointer-events: none;
}

.notification {
  padding: var(--spacing-4) var(--spacing-6);
  border-radius: var(--radius-lg);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  box-shadow: var(--shadow-lg);
  transform: translateX(100%);
  opacity: 0;
  animation: slideInNotification 0.3s ease-out forwards;
  pointer-events: auto;
}

.notification.success {
  background-color: var(--color-success);
  color: var(--color-white);
}

.notification.error {
  background-color: var(--color-error);
  color: var(--color-white);
}

.notification.hide {
  animation: slideOutNotification 0.3s ease-in forwards;
}

@keyframes slideInNotification {
  from {
    transform: translateX(100%);
    opacity: 0;
  }
  to {
    transform: translateX(0);
    opacity: 1;
  }
}

@keyframes slideOutNotification {
  from {
    transform: translateX(0);
    opacity: 1;
  }
  to {
    transform: translateX(100%);
    opacity: 0;
  }
}

@media (max-width: 640px) {
  :root {
    --font-size-2xl: 1.25rem;
    --font-size-3xl: 1.5rem;
    --font-size-4xl: 1.875rem;
    --font-size-5xl: 2.25rem;
  }
  
  .container {
    padding: 0 var(--spacing-3);
  }
  
  .header {
    padding: var(--spacing-6) 0 var(--spacing-4);
  }

  .url-input {
    padding: var(--spacing-5);
    font-size: var(--font-size-xl);
  }
  
  .submit-button {
    padding: var(--spacing-5) var(--spacing-10);
    font-size: var(--font-size-xl);
    min-height: 3.5rem;
  }
  
  .short-url {
    font-size: var(--font-size-2xl);
    padding: var(--spacing-5);
  }
  
  .action-buttons {
    flex-direction: column;
    width: 100%;
  }
  
  .action-button {
    width: 100%;
    justify-content: center;
  }
  
  .notification-container {
    top: var(--spacing-2);
    right: var(--spacing-2);
    left: var(--spacing-2);
  }
  
  .notification {
    margin: 0;
  }
}

@media (max-width: 480px) {
  .url-form {
    gap: var(--spacing-5);
  }
  
  .result-container {
    gap: var(--spacing-6);
  }
  
  .qr-code {
    max-width: 160px;
  }
}

@media print {
  body {
    background: white;
    color: black;
  }
  
  .header,
  .footer,
  .action-buttons,
  .notification-container {
    display: none;
  }
  
  .container {
    max-width: none;
    margin: 0;
    padding: 0;
    min-height: auto;
  }
  
  .main {
    padding: 20mm;
  }
  
  .qr-code {
    max-width: 100mm;
    height: auto;
  }
  
  .short-url {
    font-size: 12pt;
    padding: 10mm;
    border: 1px solid black;
  }
}

@media (prefers-contrast: high) {
  :root {
    --color-border: var(--color-gray-400);
    --color-border-focus: var(--color-gray-600);
  }
  
  .url-input:focus,
  .action-button:hover {
    box-shadow: 0 0 0 2px var(--color-primary);
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  
  .loading-spinner {
    animation: none;
  }
}

@supports selector(:focus-visible) {
  .submit-button:focus:not(:focus-visible),
  .copy-button:focus:not(:focus-visible),
  .action-button:focus:not(:focus-visible) {
    outline: none;
    box-shadow: none;
  }
  
  .submit-button:focus-visible,
  .copy-button:focus-visible,
  .action-button:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
  }
}