/**
 * MODERN BUTTON COMPONENTS
 * Beautiful buttons với gradients, ghost styles, và loading states
 * Created: 2026-03-06
 */

/* ============================================
   BASE BUTTON IMPROVEMENTS
   ============================================ */
.btn {
    font-weight: var(--font-weight-medium);
    border-radius: var(--radius-lg);
    padding: var(--spacing-3) var(--spacing-5);
    transition: all var(--transition-fast);
    border: none;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-2);
    position: relative;
    overflow: hidden;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn:active {
    transform: translateY(0);
}

.btn:focus {
    outline: none;
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
}

/* ============================================
   GRADIENT BUTTONS
   ============================================ */
.btn-gradient {
    background: var(--gradient-primary);
    color: white;
    border: none;
    box-shadow: var(--shadow-md);
    font-weight: var(--font-weight-semibold);
}

.btn-gradient::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.2), transparent);
    opacity: 0;
    transition: opacity var(--transition-fast);
}

.btn-gradient:hover::before {
    opacity: 1;
}

.btn-gradient:hover {
    box-shadow: var(--shadow-glow);
    transform: translateY(-2px) scale(1.02);
}

.btn-gradient:active {
    transform: scale(0.98);
}

/* Gradient variants */
.btn-gradient-success {
    background: var(--gradient-success);
}

.btn-gradient-success:hover {
    box-shadow: 0 0 20px rgba(16, 185, 129, 0.4);
}

.btn-gradient-warning {
    background: var(--gradient-warning);
}

.btn-gradient-warning:hover {
    box-shadow: 0 0 20px rgba(245, 158, 11, 0.4);
}

.btn-gradient-danger {
    background: var(--gradient-danger);
}

.btn-gradient-danger:hover {
    box-shadow: 0 0 20px rgba(239, 68, 68, 0.4);
}

/* ============================================
   GHOST BUTTONS (Outline with hover fill)
   ============================================ */
.btn-ghost {
    background: transparent;
    border: 2px solid var(--color-primary);
    color: var(--color-primary);
    font-weight: var(--font-weight-semibold);
    position: relative;
    overflow: hidden;
}

.btn-ghost::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: var(--color-primary);
    transition: left var(--transition-base);
    z-index: -1;
}

.btn-ghost:hover {
    color: white;
    border-color: var(--color-primary);
    box-shadow: var(--shadow-glow);
}

.btn-ghost:hover::before {
    left: 0;
}

/* Ghost variants */
.btn-ghost-success {
    border-color: var(--color-success);
    color: var(--color-success);
}

.btn-ghost-success::before {
    background: var(--color-success);
}

.btn-ghost-success:hover {
    border-color: var(--color-success);
    box-shadow: 0 0 20px rgba(16, 185, 129, 0.3);
}

.btn-ghost-warning {
    border-color: var(--color-warning);
    color: var(--color-warning);
}

.btn-ghost-warning::before {
    background: var(--color-warning);
}

.btn-ghost-warning:hover {
    border-color: var(--color-warning);
    box-shadow: 0 0 20px rgba(245, 158, 11, 0.3);
}

.btn-ghost-danger {
    border-color: var(--color-danger);
    color: var(--color-danger);
}

.btn-ghost-danger::before {
    background: var(--color-danger);
}

.btn-ghost-danger:hover {
    border-color: var(--color-danger);
    box-shadow: 0 0 20px rgba(239, 68, 68, 0.3);
}

/* ============================================
   ICON BUTTONS (Square/Circle)
   ============================================ */
.btn-icon {
    width: 40px;
    height: 40px;
    padding: 0;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-lg);
}

.btn-icon.btn-icon-sm {
    width: 32px;
    height: 32px;
    font-size: var(--font-size-sm);
}

.btn-icon.btn-icon-lg {
    width: 48px;
    height: 48px;
    font-size: var(--font-size-xl);
}

.btn-icon.btn-icon-circle {
    border-radius: var(--radius-full);
}

/* ============================================
   LOADING STATE
   ============================================ */
.btn-loading {
    pointer-events: none;
    position: relative;
    color: transparent !important;
}

.btn-loading::after {
    content: '';
    position: absolute;
    width: 16px;
    height: 16px;
    top: 50%;
    left: 50%;
    margin-left: -8px;
    margin-top: -8px;
    border: 2px solid currentColor;
    border-radius: var(--radius-full);
    border-top-color: transparent;
    animation: spin 0.6s linear infinite;
    color: white;
}

.btn-ghost.btn-loading::after {
    color: var(--color-primary);
}

/* ============================================
   BUTTON SIZES
   ============================================ */
.btn-xs {
    padding: var(--spacing-1) var(--spacing-3);
    font-size: var(--font-size-xs);
    border-radius: var(--radius-md);
}

.btn-sm {
    padding: var(--spacing-2) var(--spacing-4);
    font-size: var(--font-size-sm);
}

.btn-lg {
    padding: var(--spacing-4) var(--spacing-8);
    font-size: var(--font-size-lg);
    border-radius: var(--radius-xl);
}

.btn-xl {
    padding: var(--spacing-5) var(--spacing-10);
    font-size: var(--font-size-xl);
    border-radius: var(--radius-2xl);
}

/* ============================================
   BUTTON BLOCK (Full Width)
   ============================================ */
.btn-block {
    display: flex;
    width: 100%;
}

/* ============================================
   SOFT BUTTONS (Light background)
   ============================================ */
.btn-soft-primary {
    background: rgba(59, 130, 246, 0.1);
    color: var(--color-primary);
    border: none;
}

.btn-soft-primary:hover {
    background: rgba(59, 130, 246, 0.15);
    color: var(--color-primary-dark);
}

.btn-soft-success {
    background: rgba(16, 185, 129, 0.1);
    color: var(--color-success);
}

.btn-soft-success:hover {
    background: rgba(16, 185, 129, 0.15);
}

.btn-soft-warning {
    background: rgba(245, 158, 11, 0.1);
    color: var(--color-warning);
}

.btn-soft-warning:hover {
    background: rgba(245, 158, 11, 0.15);
}

.btn-soft-danger {
    background: rgba(239, 68, 68, 0.1);
    color: var(--color-danger);
}

.btn-soft-danger:hover {
    background: rgba(239, 68, 68, 0.15);
}

/* ============================================
   RIPPLE EFFECT
   ============================================ */
.btn-ripple {
    position: relative;
    overflow: hidden;
}

.btn-ripple::after {
    content: '';
    position: absolute;
    width: 100%;
    height: 100%;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) scale(0);
    background: rgba(255, 255, 255, 0.3);
    border-radius: var(--radius-full);
    opacity: 0;
    pointer-events: none;
}

.btn-ripple:active::after {
    animation: ripple 0.6s ease-out;
}

@keyframes ripple {
    0% {
        transform: translate(-50%, -50%) scale(0);
        opacity: 1;
    }
    100% {
        transform: translate(-50%, -50%) scale(4);
        opacity: 0;
    }
}

/* ============================================
   BUTTON GROUP
   ============================================ */
.btn-group {
    display: inline-flex;
    gap: 0;
}

.btn-group .btn {
    border-radius: 0;
    margin: 0;
}

.btn-group .btn:first-child {
    border-top-left-radius: var(--radius-lg);
    border-bottom-left-radius: var(--radius-lg);
}

.btn-group .btn:last-child {
    border-top-right-radius: var(--radius-lg);
    border-bottom-right-radius: var(--radius-lg);
}

.btn-group .btn:not(:last-child) {
    border-right: 1px solid rgba(255, 255, 255, 0.2);
}

/* ============================================
   DISABLED STATE
   ============================================ */
.btn:disabled,
.btn.disabled {
    opacity: 0.5;
    cursor: not-allowed;
    pointer-events: none;
}

/* ============================================
   BUTTON WITH ICONS
   ============================================ */
.btn i {
    font-size: 1.1em;
}

.btn-icon-left i {
    margin-right: var(--spacing-2);
}

.btn-icon-right i {
    margin-left: var(--spacing-2);
}

/* ============================================
   FLOATING ACTION BUTTON (FAB)
   ============================================ */
.btn-fab {
    width: 56px;
    height: 56px;
    border-radius: var(--radius-full);
    padding: 0;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-xl);
    position: fixed;
    bottom: var(--spacing-8);
    right: var(--spacing-8);
    z-index: var(--z-sticky);
}

.btn-fab:hover {
    transform: scale(1.1);
    box-shadow: var(--shadow-2xl);
}

.btn-fab i {
    font-size: var(--font-size-2xl);
}

/* ============================================
   BOOTSTRAP OVERRIDE
   ============================================ */
.btn-primary {
    background: var(--color-primary);
    border-color: var(--color-primary);
}

.btn-primary:hover {
    background: var(--color-primary-dark);
    border-color: var(--color-primary-dark);
}

.btn-success {
    background: var(--color-success);
    border-color: var(--color-success);
}

.btn-warning {
    background: var(--color-warning);
    border-color: var(--color-warning);
}

.btn-danger {
    background: var(--color-danger);
    border-color: var(--color-danger);
}

/* ============================================
   RESPONSIVE
   ============================================ */
@media (max-width: 768px) {
    .btn {
        padding: var(--spacing-2) var(--spacing-4);
        font-size: var(--font-size-sm);
    }

    .btn-lg {
        padding: var(--spacing-3) var(--spacing-6);
        font-size: var(--font-size-base);
    }

    .btn-fab {
        width: 48px;
        height: 48px;
        bottom: var(--spacing-6);
        right: var(--spacing-6);
    }

    .btn-fab i {
        font-size: var(--font-size-xl);
    }
}