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

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  min-height: 100vh;
}

h1, h2, h3, h4 {
  line-height: 1.3;
  font-weight: 600;
}

h1 { font-size: 1.75rem; }
h2 { font-size: 1.35rem; }
h3 { font-size: 1.1rem; }

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

a:hover {
  text-decoration: underline;
}

code {
  background: var(--color-code-bg);
  padding: 0.15em 0.4em;
  border-radius: 3px;
  font-size: 0.9em;
  font-family: 'SF Mono', 'Fira Code', monospace;
}

input, select, textarea, button {
  font-family: inherit;
  font-size: inherit;
}

input[type="number"],
input[type="text"],
select,
textarea {
  background: var(--color-input-bg);
  color: var(--color-text);
  border: 1px solid var(--color-input-border);
  border-radius: var(--radius);
  padding: 0.5rem 0.75rem;
}

input[type="number"]:focus,
input[type="text"]:focus,
select:focus,
textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.2);
}

.btn-primary {
  background: var(--color-primary);
  color: var(--color-primary-text);
  border: none;
  border-radius: var(--radius);
  padding: 0.65rem 1.25rem;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.15s;
  width: 100%;
}

.btn-primary:hover:not(:disabled) {
  background: var(--color-primary-hover);
}

.btn-primary:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-secondary {
  background: var(--color-surface-alt);
  color: var(--color-text);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 0.5rem 1rem;
  cursor: pointer;
  transition: background 0.15s;
}

.btn-secondary:hover:not(:disabled) {
  background: var(--color-border);
}

.btn-secondary:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.btn-text {
  background: none;
  border: none;
  color: var(--color-primary);
  cursor: pointer;
  font-size: 0.85rem;
}

.btn-text:hover {
  text-decoration: underline;
}