/* ========================================
   DARK MODE THEME TOGGLE BUTTON
   ======================================== */

.theme-toggle {
    position: fixed;
    bottom: var(--space-8);
    right: var(--space-8);
    width: 60px;
    height: 60px;
    border-radius: var(--radius-circle);
    background: var(--color-primary);
    color: white;
    font-size: var(--font-size-xl);
    border: none;
    cursor: pointer;
    box-shadow: var(--shadow-lg);
    z-index: var(--z-index-tooltip);
    transition: var(--transition-all);
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle:hover {
    transform: scale(1.1) rotate(20deg);
    box-shadow: var(--shadow-xl);
}

.theme-toggle:active {
    transform: scale(0.95);
}

/* ========================================
   READING PROGRESS BAR
   ======================================== */

#reading-progress {
    position: fixed;
    top: 0;
    left: 0;
    height: 4px;
    background: var(--gradient-primary);
    width: 0%;
    z-index: var(--z-index-toast);
    transition: width 0.1s ease-out;
}

/* ========================================
   TOAST NOTIFICATIONS
   ======================================== */

.toast-container {
    position: fixed;
    top: var(--space-8);
    right: var(--space-8);
    z-index: var(--z-index-toast);
    display: flex;
    flex-direction: column;
    gap: var(--space-4);
}

.toast {
    background: var(--color-bg-secondary);
    color: var(--color-text-primary);
    padding: var(--space-4) var(--space-6);
    border-radius: var(--radius-base);
    box-shadow: var(--shadow-xl);
    min-width: 300px;
    max-width: 500px;
    animation: slideInRight 0.3s ease-out;
    border-left: 4px solid var(--color-info);
}

.toast.success {
    border-left-color: var(--color-success);
}

.toast.error {
    border-left-color: var(--color-error);
}

.toast.warning {
    border-left-color: var(--color-warning);
}

.toast.info {
    border-left-color: var(--color-info);
}

@keyframes slideInRight {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

/* ========================================
   LAZY LOADING IMAGES
   ======================================== */

img[loading="lazy"] {
    opacity: 0;
    transition: opacity var(--transition-medium) var(--ease-in-out);
}

img[loading="lazy"].loaded {
    opacity: 1;
}

/* ========================================
   LOADING SPINNERS
   ======================================== */

.spinner {
    border: 3px solid var(--color-border-primary);
    border-top: 3px solid var(--color-primary);
    border-radius: var(--radius-circle);
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
}

.spinner-sm {
    width: 20px;
    height: 20px;
    border-width: 2px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* ========================================
   FOCUS STYLES (Accessibility)
   ======================================== */

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

button:focus-visible, a:focus-visible {
    box-shadow: var(--shadow-focus-primary);
}

/* ========================================
   UTILITY CLASSES
   ======================================== */

/* Spacing utilities */
.m-0 { margin: var(--space-0) !important; }
.m-2 { margin: var(--space-2) !important; }
.m-4 { margin: var(--space-4) !important; }
.m-6 { margin: var(--space-6) !important; }
.m-8 { margin: var(--space-8) !important; }

.mt-0 { margin-top: var(--space-0) !important; }
.mt-2 { margin-top: var(--space-2) !important; }
.mt-4 { margin-top: var(--space-4) !important; }
.mt-6 { margin-top: var(--space-6) !important; }
.mt-8 { margin-top: var(--space-8) !important; }

.mb-0 { margin-bottom: var(--space-0) !important; }
.mb-2 { margin-bottom: var(--space-2) !important; }
.mb-4 { margin-bottom: var(--space-4) !important; }
.mb-6 { margin-bottom: var(--space-6) !important; }
.mb-8 { margin-bottom: var(--space-8) !important; }

.p-0 { padding: var(--space-0) !important; }
.p-2 { padding: var(--space-2) !important; }
.p-4 { padding: var(--space-4) !important; }
.p-6 { padding: var(--space-6) !important; }
.p-8 { padding: var(--space-8) !important; }

/* Display utilities */
.d-none { display: none !important; }
.d-block { display: block !important; }
.d-flex { display: flex !important; }
.d-grid { display: grid !important; }

/* Flex utilities */
.flex-column { flex-direction: column !important; }
.flex-row { flex-direction: row !important; }
.justify-center { justify-content: center !important; }
.justify-between { justify-content: space-between !important; }
.align-center { align-items: center !important; }
.gap-2 { gap: var(--space-2) !important; }
.gap-4 { gap: var(--space-4) !important; }
.gap-6 { gap: var(--space-6) !important; }

/* Text utilities */
.text-left { text-align: left !important; }
.text-center { text-align: center !important; }
.text-right { text-align: right !important; }

.font-normal { font-weight: var(--font-weight-normal) !important; }
.font-medium { font-weight: var(--font-weight-medium) !important; }
.font-semibold { font-weight: var(--font-weight-semibold) !important; }
.font-bold { font-weight: var(--font-weight-bold) !important; }

/* Color utilities */
.text-primary { color: var(--color-primary) !important; }
.text-accent { color: var(--color-accent) !important; }
.text-success { color: var(--color-success) !important; }
.text-warning { color: var(--color-warning) !important; }
.text-error { color: var(--color-error) !important; }
.text-muted { color: var(--color-text-tertiary) !important; }

.bg-primary { background-color: var(--color-primary) !important; }
.bg-accent { background-color: var(--color-accent) !important; }
.bg-light { background-color: var(--color-bg-tertiary) !important; }

/* Border utilities */
.border { border: var(--border-width-thin) solid var(--color-border-primary) !important; }
.border-top { border-top: var(--border-width-thin) solid var(--color-border-primary) !important; }
.border-bottom { border-bottom: var(--border-width-thin) solid var(--color-border-primary) !important; }
.border-left { border-left: var(--border-width-thin) solid var(--color-border-primary) !important; }
.border-right { border-right: var(--border-width-thin) solid var(--color-border-primary) !important; }

.rounded { border-radius: var(--radius-base) !important; }
.rounded-sm { border-radius: var(--radius-sm) !important; }
.rounded-lg { border-radius: var(--radius-lg) !important; }
.rounded-full { border-radius: var(--radius-full) !important; }

/* Shadow utilities */
.shadow-sm { box-shadow: var(--shadow-sm) !important; }
.shadow { box-shadow: var(--shadow-base) !important; }
.shadow-md { box-shadow: var(--shadow-md) !important; }
.shadow-lg { box-shadow: var(--shadow-lg) !important; }
.shadow-none { box-shadow: none !important; }

/* ========================================
   ACCESSIBILITY & MOTION
   ======================================== */

/* Reduced motion for accessibility */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Screen reader only */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

/* ========================================
   PRINT STYLES
   ======================================== */

@media print {
    .navbar, .theme-toggle, .toast-container, footer, .btn {
        display: none !important;
    }

    body {
        background: white;
        color: black;
    }

    .content-card {
        box-shadow: none;
        border: 1px solid #ddd;
    }
}