/* ============================================================================
   UTILITY CLASSES
   Low-level, single-purpose classes with u- prefix
   ============================================================================ */

/* Flexbox */
.u-flex { display: flex; }
.u-flex-col { display: flex; flex-direction: column; }
.u-inline-flex { display: inline-flex; }
.u-items-center { align-items: center; }
.u-items-start { align-items: flex-start; }
.u-justify-between { justify-content: space-between; }
.u-justify-center { justify-content: center; }
.u-flex-1 { flex: 1; }
.u-flex-1-min { flex: 1; min-width: 0; }
.u-flex-shrink-0 { flex-shrink: 0; }
.u-flex-wrap { flex-wrap: wrap; }

/* Gap (4px base scale + compatibility values) */
.u-gap-1 { gap: 0.25rem; }   /* 4px */
.u-gap-2 { gap: 0.5rem; }    /* 8px */
.u-gap-3 { gap: 0.75rem; }   /* 12px */
.u-gap-4 { gap: 1rem; }      /* 16px */
.u-gap-5 { gap: 1.25rem; }   /* 20px */
.u-gap-6 { gap: 1.5rem; }    /* 24px */
/* Non-standard gaps for existing code compatibility */
.u-gap-xs { gap: 0.125rem; } /* 2px */
.u-gap-sm { gap: 0.375rem; } /* 6px */
.u-gap-md { gap: 0.625rem; } /* 10px */

/* Margin */
.u-m-0 { margin: 0; }
.u-mt-1 { margin-top: 0.25rem; }
.u-mt-2 { margin-top: 0.5rem; }
.u-mt-3 { margin-top: 0.75rem; }
.u-mt-4 { margin-top: 1rem; }
.u-mt-8 { margin-top: 2rem; }
.u-mb-1 { margin-bottom: 0.25rem; }
.u-mb-2 { margin-bottom: 0.5rem; }
.u-mb-3 { margin-bottom: 0.75rem; }
.u-mb-4 { margin-bottom: 1rem; }
.u-mb-6 { margin-bottom: 1.5rem; }

/* Padding */
.u-p-2 { padding: 0.5rem; }
.u-p-3 { padding: 0.75rem; }
.u-p-4 { padding: 1rem; }
.u-p-5 { padding: 1.25rem; }
.u-p-6 { padding: 1.5rem; }
.u-p-8 { padding: 2rem; }
.u-px-2 { padding-left: 0.5rem; padding-right: 0.5rem; }
.u-px-3 { padding-left: 0.75rem; padding-right: 0.75rem; }
.u-px-4 { padding-left: 1rem; padding-right: 1rem; }
.u-px-6 { padding-left: 1.5rem; padding-right: 1.5rem; }
.u-py-2 { padding-top: 0.5rem; padding-bottom: 0.5rem; }
.u-py-3 { padding-top: 0.75rem; padding-bottom: 0.75rem; }
.u-py-4 { padding-top: 1rem; padding-bottom: 1rem; }

/* Typography */
.u-text-2xs { font-size: 0.65rem; }
.u-text-xs { font-size: 0.75rem; }
.u-text-sm { font-size: 0.8rem; }
.u-text-md { font-size: 0.875rem; }
.u-text-base { font-size: 0.9rem; }
.u-text-lg { font-size: 1rem; }
.u-text-xl { font-size: 1.25rem; }
.u-text-1-5 { font-size: 1.5rem; }
.u-text-1-75 { font-size: 1.75rem; }
.u-font-medium { font-weight: 500; }
.u-font-semibold { font-weight: 600; }
.u-text-center { text-align: center; }
.u-text-left { text-align: left; }
.u-leading-none { line-height: 1; }

/* Text overflow */
.u-truncate {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}
.u-whitespace-nowrap { white-space: nowrap; }

/* Text colors (using CSS vars) */
.u-text-primary { color: var(--rb-text-primary); }
.u-text-secondary { color: var(--rb-text-secondary); }
.u-text-muted { color: var(--rb-text-muted); }
.u-text-dimmed { color: var(--rb-text-dimmed); }
.u-text-error { color: var(--rb-color-error); }
.u-text-success { color: var(--rb-color-success); }
.u-text-info { color: var(--rb-color-info); }
.u-text-purple { color: #c7d2fe; }
.u-text-purple-light { color: #a5b4fc; }
.u-text-white { color: white; }

/* Background colors */
.u-bg-base { background: var(--rb-bg-base); }
.u-bg-surface { background: var(--rb-bg-surface); }
.u-bg-elevated { background: var(--rb-bg-elevated); }
.u-bg-transparent { background: transparent; }
.u-bg-blue { background: var(--rb-color-info); }
.u-bg-green { background: var(--rb-color-success); }
.u-bg-purple { background: var(--rb-color-purple); }
.u-bg-red { background: #dc2626; }
.u-bg-error { background: var(--rb-color-error-dark); }
.u-bg-success { background: var(--rb-color-success-dark); }
.u-bg-info { background: var(--rb-color-info-dark); }

/* Border radius */
.u-rounded-sm { border-radius: 4px; }
.u-rounded-md { border-radius: 6px; }
.u-rounded-lg { border-radius: 8px; }
.u-rounded-xl { border-radius: 12px; }
.u-rounded-2xl { border-radius: 16px; }
.u-rounded-full { border-radius: 9999px; }
.u-rounded-none { border-radius: 0; }

/* Borders */
.u-border { border: 1px solid var(--rb-border-default); }
.u-border-dark { border: 1px solid var(--rb-border-dark); }
.u-border-purple { border: 1px solid var(--rb-border-purple); }
.u-border-error { border: 1px solid var(--rb-color-error-border); }
.u-border-dashed { border-style: dashed; }
.u-border-none { border: none; }
.u-border-t { border-top: 1px solid var(--rb-border-default); }
.u-border-b { border-bottom: 1px solid var(--rb-border-default); }
.u-border-r { border-right: 1px solid var(--rb-border-dark); }

/* Width */
.u-w-full { width: 100%; }
.u-max-w-600 { max-width: 600px; }
.u-max-w-700 { max-width: 700px; }

/* Height */
.u-min-h-80 { min-height: 80px; }
.u-min-h-120 { min-height: 120px; }
.u-max-h-90vh { max-height: 90vh; }
.u-max-h-300 { max-height: 300px; }

/* Cursor */
.u-cursor-pointer { cursor: pointer; }
.u-cursor-default { cursor: default; }

/* Overflow */
.u-overflow-hidden { overflow: hidden; }
.u-overflow-auto { overflow: auto; }
.u-overflow-y-auto { overflow-y: auto; }

/* Transitions */
.u-transition { transition: all 0.2s; }
.u-transition-colors { transition: color 0.2s, background-color 0.2s, border-color 0.2s; }
.u-transition-fast { transition: all 0.15s; }

/* Visibility */
.u-sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    border: 0;
}

/* Resize */
.u-resize-vertical { resize: vertical; }
.u-resize-none { resize: none; }