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

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  padding-top: env(safe-area-inset-top);
  padding-bottom: env(safe-area-inset-bottom);
  padding-left: env(safe-area-inset-left);
  padding-right: env(safe-area-inset-right);
}

#app {
  max-width: var(--max-width);
  margin: 0 auto;
  min-height: 100vh;
  position: relative;
  padding-bottom: var(--space-2xl);
}

a {
  color: var(--teal);
  text-decoration: none;
}

button {
  font-family: var(--font-sans);
  cursor: pointer;
  border: none;
  -webkit-tap-highlight-color: transparent;
}

input, textarea {
  font-family: var(--font-sans);
  border: none;
}

button:focus-visible, input:focus-visible, textarea:focus-visible {
  outline: 2px solid var(--teal);
  outline-offset: 2px;
}

img {
  max-width: 100%;
  display: block;
}

::-webkit-scrollbar {
  width: 4px;
}

::-webkit-scrollbar-track {
  background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
  background: var(--text-muted);
  border-radius: var(--radius-full);
}

/* Utility classes */
.screen {
  padding: var(--header-height) var(--space-md) var(--space-lg);
  min-height: 100vh;
  animation: fadeIn var(--transition-normal);
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

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

@keyframes pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.05); }
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-5px); }
  75% { transform: translateX(5px); }
}

@keyframes bounceIn {
  0% { transform: scale(0); opacity: 0; }
  50% { transform: scale(1.2); }
  100% { transform: scale(1); opacity: 1; }
}

@keyframes glow {
  0%, 100% { box-shadow: var(--shadow-glow-teal); }
  50% { box-shadow: 0 0 30px rgba(0, 212, 170, 0.5); }
}

#toast-container {
  position: fixed;
  top: var(--space-lg);
  left: 50%;
  transform: translateX(-50%);
  z-index: 1000;
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  pointer-events: none;
  max-width: var(--max-width);
  width: 100%;
  padding: 0 var(--space-md);
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !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: 0;
}

/* === Responsive Breakpoints === */

/* iPhone SE / small phones (375px and below) */
@media (max-width: 380px) {
  :root {
    --space-md: 12px;
    --space-lg: 16px;
    --text-2xl: 1.25rem;
    --text-3xl: 1.75rem;
    --text-4xl: 2rem;
  }

  .screen {
    padding-left: var(--space-sm);
    padding-right: var(--space-sm);
  }
}

/* iPad and tablets (768px+) */
@media (min-width: 768px) {
  :root {
    --max-width: 640px;
    --header-height: 60px;
    --text-lg: 1.25rem;
    --text-xl: 1.5rem;
    --text-2xl: 1.75rem;
    --text-3xl: 2.25rem;
    --text-4xl: 3rem;
  }

  #app {
    padding-top: var(--space-lg);
  }
}

/* iPad landscape / large tablets (1024px+) */
@media (min-width: 1024px) {
  :root {
    --max-width: 720px;
  }
}