/**
 * Button Components
 * 
 * Unified button styles following design system tokens
 * BEM naming convention for maintainability
 */

/* Base Button Styles */
.button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-2);
    padding: var(--spacing-3) var(--spacing-6);
    border: var(--border-width-base) solid transparent;
    border-radius: var(--border-radius-base);
    font-family: var(--font-family-base);
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-semibold);
    line-height: var(--line-height-normal);
    text-decoration: none;
    cursor: pointer;
    transition: var(--transition-base);
    white-space: nowrap;
    user-select: none;
    -webkit-user-select: none;
    touch-action: manipulation;
    position: relative;
    overflow: hidden;
}

/* Smooth animations for all buttons */
.button {
    transform: translateZ(0);
    backface-visibility: hidden;
    -webkit-font-smoothing: antialiased;
}

.button:focus {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

.button:disabled,
.button[disabled] {
    opacity: 0.6;
    cursor: not-allowed;
    pointer-events: none;
}

/* Primary Button Variant */
.button--primary {
    background: var(--gradient-primary);
    color: var(--color-dark);
    border-color: var(--color-primary);
    box-shadow: var(--shadow);
}

.button--primary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    filter: brightness(1.05);
}

.button--primary:active:not(:disabled) {
    transform: translateY(0);
    box-shadow: var(--shadow-sm);
}

/* Secondary Button Variant */
.button--secondary {
    background: var(--color-light);
    color: var(--color-text);
    border-color: var(--color-border);
    box-shadow: var(--shadow-sm);
}

.button--secondary:hover:not(:disabled) {
    background: var(--color-gray-50);
    border-color: var(--color-primary);
    color: var(--color-primary-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow);
}

.button--secondary:active:not(:disabled) {
    transform: translateY(0);
    box-shadow: var(--shadow-sm);
}

/* Tertiary Button Variant */
.button--tertiary {
    background: transparent;
    color: var(--color-text);
    border-color: transparent;
}

.button--tertiary:hover:not(:disabled) {
    background: var(--color-gray-100);
    color: var(--color-primary-dark);
}

.button--tertiary:active:not(:disabled) {
    background: var(--color-gray-200);
}

/* Button Sizes */
.button--small {
    padding: var(--spacing-2) var(--spacing-4);
    font-size: var(--font-size-sm);
}

.button--large {
    padding: var(--spacing-4) var(--spacing-8);
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-bold);
}

/* Button with Icon */
.button__icon {
    display: inline-flex;
    align-items: center;
    font-size: 1.2em;
}

.button__icon--left {
    order: -1;
}

.button__icon--right {
    order: 1;
}

/* Loading State */
.button--loading {
    position: relative;
    color: transparent;
    pointer-events: none;
}

.button--loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 1em;
    height: 1em;
    margin-top: -0.5em;
    margin-left: -0.5em;
    border: 2px solid currentColor;
    border-right-color: transparent;
    border-radius: 50%;
    animation: button-spin 0.6s linear infinite;
}

@keyframes button-spin {
    to {
        transform: rotate(360deg);
    }
}

/* Respect reduced motion preference */
@media (prefers-reduced-motion: reduce) {
    .button {
        transition: none;
    }
    
    .button:hover:not(:disabled) {
        transform: none;
    }
    
    .button--loading::after {
        animation: none;
    }
}