.fl-crystal {
    /* Base colors for light and dark modes */
    --crystal-bg-light: #ffffff;                  /* Pure white background in light mode */
    --crystal-bg-dark: rgba(30, 30, 30, 0.95);    /* Near-black in dark mode */
    --crystal-text-light: #2c3e50;                /* Deep blue-gray text for light mode */
    --crystal-text-dark: rgba(255, 255, 255, 0.95); /* Off-white text for dark mode */
    /* Shadow colors for animations and effects */
    --crystal-shadow: rgba(0, 0, 0, 0.08);        /* Subtle shadow for light mode */
    --crystal-shadow-dark: rgba(0, 0, 0, 0.25);   /* Stronger shadow for dark mode */
}
@keyframes crystalIn {
    from {
        opacity: 0;
        transform: translateY(-20px);             /* Start above final position */
    }
    to {
        opacity: 1;
        transform: translateY(0);                 /* End at natural position */
    }
}
@keyframes crystalPulse {
    0% {
        box-shadow: 0 2px 8px var(--crystal-shadow);  /* Start with normal shadow */
    }
    50% {
        box-shadow: 0 4px 12px var(--crystal-shadow); /* Peak with larger shadow */
    }
    100% {
        box-shadow: 0 2px 8px var(--crystal-shadow);  /* Return to normal shadow */
    }
}
.fl-crystal {
    position: relative;
    background: var(--crystal-bg-light, var(--fl-bg-light));
    margin: 0 0 1rem 0;                           /* Space between stacked notifications */
    font-family: var(--fl-font), serif;
    animation: crystalIn 0.3s ease-out;           /* Entrance animation */
    box-shadow: 0 2px 8px var(--crystal-shadow);  /* Default shadow */
    border-radius: var(--fl-border-radius, 4px) var(--fl-border-radius, 4px) 0 0;  /* Rounded corners */
    will-change: transform, opacity;              /* Optimize for animation performance */
    transition: box-shadow 0.3s ease;             /* Smooth transition for shadow changes */
    /**
     * Hover effect
     * Applies pulsing animation when notification is hovered
     */
    &:hover {
        animation: crystalPulse 2s ease-in-out infinite;
    }
    /**
     * Content container
     * Holds the message and close button
     */
    .fl-content {
        padding: 1rem 2.5rem 1rem 1rem;           /* Space for close button on right */
        display: flex;
        align-items: center;
        gap: 0.75rem;                             /* Space between elements */
    }
    /**
     * Text container
     * Holds the message paragraph
     */
    .fl-text {
        flex: 1;                                  /* Take available space */
    }
    /**
     * Message styling
     * The primary notification text
     */
    .fl-message {
        margin: 0;
        font-size: 0.9375rem;                     /* 15px at default font size */
        line-height: 1.4;                         /* Improved readability */
        color: var(--crystal-text-light, var(--fl-text-light));
    }
    /**
     * Close button styling
     * Positioned absolutely to maintain consistent layout
     */
    .fl-close {
        position: absolute;
        right: 0.75rem;
        top: 50%;                                 /* Center vertically */
        transform: translateY(-50%);              /* Fine-tune vertical centering */
        background: none;
        border: none;
        font-size: 1.25rem;
        line-height: 1;
        padding: 0.25rem;
        cursor: pointer;
        opacity: 0.5;                             /* Subtle appearance by default */
        transition: all 0.2s ease;
        color: currentColor;                      /* Inherit color from parent */
        touch-action: manipulation;               /* Better touch behavior */
        &:hover, &:focus {
            opacity: 1;                           /* Full opacity on interaction */
            transform: translateY(-50%) scale(1.1); /* Slight grow effect */
        }
    }
    /**
     * Progress bar container
     * Holds the animated progress indicator
     */
    .fl-progress-bar {
        position: absolute;
        bottom: 0;
        left: 0;
        right: 0;
        height: 3px;
        overflow: hidden;
        /**
         * Progress indicator
         * Animated by JavaScript to show remaining time
         */
        .fl-progress {
            height: 100%;
            width: 100%;
            transform-origin: left center;        /* Animation starts from left */
        }
    }
    /**
     * Type-specific styling
     * Each notification type gets its own text color
     */
    &.fl-success {
        color: var(--success-color, var(--fl-success));
        .fl-message { color: var(--success-color, var(--fl-success)); }
    }
    &.fl-error {
        color: var(--error-color, var(--fl-error));
        .fl-message { color: var(--error-color, var(--fl-error)); }
    }
    &.fl-warning {
        color: var(--warning-color, var(--fl-warning));
        .fl-message { color: var(--warning-color, var(--fl-warning)); }
    }
    &.fl-info {
        color: var(--info-color, var(--fl-info));
        .fl-message { color: var(--info-color, var(--fl-info)); }
    }
    /**
     * RTL support
     * Right-to-left language direction support
     */
    &.fl-rtl {
        direction: rtl;
        .fl-content {
            padding: 1rem 1rem 1rem 2.5rem;       /* Swap padding for close button on left */
        }
        .fl-close {
            right: auto;
            left: 0.75rem;                        /* Move close button to left side */
        }
        .fl-progress .fl-progress {
            transform-origin: right center;       /* Animation starts from right */
        }
    }
    /**
     * Accessibility
     * Respects reduced motion preferences
     */
    @media (prefers-reduced-motion: reduce) {
        animation: none;                          /* Disable entrance animation */
        &:hover {
            animation: none;                      /* Disable pulse animation */
            box-shadow: 0 2px 8px var(--crystal-shadow); /* Keep default shadow */
        }
    }
}
body.fl-dark .fl-crystal,
html.fl-dark .fl-crystal,
.fl-crystal.fl-auto-dark {
    background-color: var(--crystal-bg-dark, var(--fl-bg-dark));
    box-shadow: 0 2px 8px var(--crystal-shadow-dark);
    .fl-message {
        color: var(--crystal-text-dark, var(--fl-text-dark));
    }
    &:hover {
        animation: none;                          /* Disable pulse in dark mode */
        box-shadow: 0 4px 16px var(--crystal-shadow-dark); /* Use static enhanced shadow instead */
    }
}