/* ==========================================
   PAGE LOADER STYLES - FULLY RESPONSIVE
   Matches ExamGuru theme colors and design
   ========================================== */

/* Main Loader Container */
#page-loader {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, #0a0a0a 0%, #1a1a2e 30%, #16213e 60%, #0f3460 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    transition: opacity 0.6s ease-out, visibility 0.6s ease-out;
    overflow: hidden;
}

#page-loader::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 
        radial-gradient(circle at 20% 80%, rgba(0, 150, 255, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(255, 255, 255, 0.08) 0%, transparent 50%),
        radial-gradient(circle at 40% 40%, rgba(0, 200, 255, 0.12) 0%, transparent 50%);
    animation: loaderBackgroundPulse 8s ease-in-out infinite alternate;
}

@keyframes loaderBackgroundPulse {
    0% { opacity: 0.6; transform: scale(1); }
    100% { opacity: 0.9; transform: scale(1.02); }
}

#page-loader.loaded {
    opacity: 0;
    visibility: hidden;
}

/* Loader Container */
.loader-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 25px;
    text-align: center;
    position: relative;
    z-index: 10;
    max-width: 90%;
    padding: 20px;
}

/* Logo */
.loader-logo {
    font-size: 3rem;
    font-weight: 700;
    color: #00d4ff;
    margin-bottom: 5px;
    text-shadow: 0 0 30px rgba(0, 212, 255, 0.6);
    animation: logoGlow 3s ease-in-out infinite alternate;
    display: flex;
    align-items: center;
    gap: 15px;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

.loader-logo i {
    font-size: 3.5rem;
    animation: logoRotate 4s ease-in-out infinite;
}

@keyframes logoGlow {
    0% { 
        text-shadow: 0 0 20px rgba(0, 212, 255, 0.4);
        transform: scale(1);
    }
    100% { 
        text-shadow: 0 0 40px rgba(0, 212, 255, 0.8);
        transform: scale(1.02);
    }
}

@keyframes logoRotate {
    0%, 100% { transform: rotate(0deg); }
    25% { transform: rotate(-5deg); }
    75% { transform: rotate(5deg); }
}

/* Subtitle */
.loader-subtitle {
    font-size: 1.2rem;
    color: rgba(255, 255, 255, 0.8);
    font-weight: 300;
    letter-spacing: 2px;
    text-transform: uppercase;
    margin-bottom: 10px;
    animation: subtitleFade 2s ease-in-out infinite alternate;
}

@keyframes subtitleFade {
    0% { opacity: 0.6; }
    100% { opacity: 1; }
}

/* Spinner */
.loader-spinner {
    position: relative;
    width: 80px;
    height: 80px;
    margin: 10px 0;
}

.spinner-ring {
    position: absolute;
    border: 3px solid transparent;
    border-radius: 50%;
    animation: spin 2s linear infinite;
}

.spinner-ring:nth-child(1) {
    width: 80px;
    height: 80px;
    border-top: 3px solid #00d4ff;
    border-right: 3px solid #00d4ff;
    animation-duration: 2s;
}

.spinner-ring:nth-child(2) {
    width: 60px;
    height: 60px;
    top: 10px;
    left: 10px;
    border-bottom: 3px solid #0099cc;
    border-left: 3px solid #0099cc;
    animation-duration: 1.5s;
    animation-direction: reverse;
}

.spinner-ring:nth-child(3) {
    width: 40px;
    height: 40px;
    top: 20px;
    left: 20px;
    border-top: 3px solid rgba(0, 212, 255, 0.6);
    border-right: 3px solid rgba(0, 212, 255, 0.6);
    animation-duration: 1s;
}

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

/* Loading Text */
.loader-text {
    font-size: 1rem;
    color: rgba(255, 255, 255, 0.7);
    font-weight: 400;
    letter-spacing: 1px;
    animation: textPulse 2s ease-in-out infinite;
    margin: 5px 0;
}

@keyframes textPulse {
    0%, 100% { opacity: 0.7; }
    50% { opacity: 1; }
}

/* Progress Bar */
.loader-progress {
    width: 250px;
    height: 4px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 10px;
    overflow: hidden;
    position: relative;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, #00d4ff, #0099cc, #00d4ff);
    background-size: 200% 100%;
    border-radius: 10px;
    animation: progressLoad 3s ease-in-out infinite, progressShimmer 2s ease-in-out infinite;
    box-shadow: 0 0 10px rgba(0, 212, 255, 0.5);
}

@keyframes progressLoad {
    0% { width: 0%; }
    50% { width: 70%; }
    100% { width: 100%; }
}

@keyframes progressShimmer {
    0% { background-position: -200% 0; }
    100% { background-position: 200% 0; }
}

/* Floating Particles */
.loader-particles {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    overflow: hidden;
}

.loader-particle {
    position: absolute;
    background: rgba(0, 212, 255, 0.3);
    border-radius: 50%;
    animation: particleFloat 15s infinite linear;
}

.loader-particle:nth-child(1) {
    width: 6px;
    height: 6px;
    left: 10%;
    animation-delay: 0s;
    animation-duration: 18s;
}

.loader-particle:nth-child(2) {
    width: 8px;
    height: 8px;
    left: 80%;
    animation-delay: 3s;
    animation-duration: 20s;
}

.loader-particle:nth-child(3) {
    width: 4px;
    height: 4px;
    left: 60%;
    animation-delay: 6s;
    animation-duration: 16s;
}

.loader-particle:nth-child(4) {
    width: 10px;
    height: 10px;
    left: 30%;
    animation-delay: 9s;
    animation-duration: 22s;
}

.loader-particle:nth-child(5) {
    width: 5px;
    height: 5px;
    left: 90%;
    animation-delay: 12s;
    animation-duration: 19s;
}

@keyframes particleFloat {
    0% {
        transform: translateY(100vh) rotate(0deg) scale(0);
        opacity: 0;
    }
    10% {
        opacity: 1;
        transform: translateY(90vh) rotate(36deg) scale(1);
    }
    90% {
        opacity: 1;
        transform: translateY(10vh) rotate(324deg) scale(1);
    }
    100% {
        transform: translateY(-10vh) rotate(360deg) scale(0);
        opacity: 0;
    }
}

/* ==========================================
   RESPONSIVE BREAKPOINTS
   ========================================== */

/* Large Desktop (1440px and above) */
@media (min-width: 1440px) {
    .loader-logo {
        font-size: 3.5rem;
    }
    
    .loader-logo i {
        font-size: 4rem;
    }
    
    .loader-subtitle {
        font-size: 1.4rem;
    }
    
    .loader-spinner {
        width: 100px;
        height: 100px;
    }
    
    .spinner-ring:nth-child(1) {
        width: 100px;
        height: 100px;
    }
    
    .spinner-ring:nth-child(2) {
        width: 75px;
        height: 75px;
        top: 12.5px;
        left: 12.5px;
    }
    
    .spinner-ring:nth-child(3) {
        width: 50px;
        height: 50px;
        top: 25px;
        left: 25px;
    }
    
    .loader-progress {
        width: 300px;
        height: 5px;
    }
    
    .loader-text {
        font-size: 1.1rem;
    }
}

/* Desktop (1024px to 1439px) */
@media (min-width: 1024px) and (max-width: 1439px) {
    .loader-logo {
        font-size: 3rem;
    }
    
    .loader-logo i {
        font-size: 3.5rem;
    }
    
    .loader-subtitle {
        font-size: 1.2rem;
    }
    
    .loader-progress {
        width: 250px;
    }
}

/* Tablet Landscape (768px to 1023px) */
@media (min-width: 768px) and (max-width: 1023px) {
    .loader-container {
        gap: 20px;
        padding: 15px;
    }
    
    .loader-logo {
        font-size: 2.5rem;
        gap: 12px;
    }
    
    .loader-logo i {
        font-size: 3rem;
    }
    
    .loader-subtitle {
        font-size: 1.1rem;
        letter-spacing: 1.5px;
    }
    
    .loader-spinner {
        width: 70px;
        height: 70px;
    }
    
    .spinner-ring:nth-child(1) {
        width: 70px;
        height: 70px;
    }
    
    .spinner-ring:nth-child(2) {
        width: 50px;
        height: 50px;
        top: 10px;
        left: 10px;
    }
    
    .spinner-ring:nth-child(3) {
        width: 30px;
        height: 30px;
        top: 20px;
        left: 20px;
    }
    
    .loader-progress {
        width: 200px;
        height: 3px;
    }
    
    .loader-text {
        font-size: 0.9rem;
    }
}

/* Tablet Portrait (481px to 767px) */
@media (min-width: 481px) and (max-width: 767px) {
    .loader-container {
        gap: 18px;
        padding: 10px;
    }
    
    .loader-logo {
        font-size: 2.2rem;
        gap: 10px;
    }
    
    .loader-logo i {
        font-size: 2.5rem;
    }
    
    .loader-subtitle {
        font-size: 1rem;
        letter-spacing: 1px;
    }
    
    .loader-spinner {
        width: 60px;
        height: 60px;
    }
    
    .spinner-ring:nth-child(1) {
        width: 60px;
        height: 60px;
    }
    
    .spinner-ring:nth-child(2) {
        width: 45px;
        height: 45px;
        top: 7.5px;
        left: 7.5px;
    }
    
    .spinner-ring:nth-child(3) {
        width: 30px;
        height: 30px;
        top: 15px;
        left: 15px;
    }
    
    .loader-progress {
        width: 180px;
        height: 3px;
    }
    
    .loader-text {
        font-size: 0.85rem;
        letter-spacing: 0.5px;
    }
}

/* Mobile Large (376px to 480px) */
@media (min-width: 376px) and (max-width: 480px) {
    .loader-container {
        gap: 15px;
        padding: 8px;
    }
    
    .loader-logo {
        font-size: 1.8rem;
        gap: 8px;
        flex-direction: column;
        text-align: center;
    }
    
    .loader-logo i {
        font-size: 2.2rem;
    }
    
    .loader-subtitle {
        font-size: 0.9rem;
        letter-spacing: 0.8px;
        margin-bottom: 5px;
    }
    
    .loader-spinner {
        width: 50px;
        height: 50px;
    }
    
    .spinner-ring:nth-child(1) {
        width: 50px;
        height: 50px;
    }
    
    .spinner-ring:nth-child(2) {
        width: 35px;
        height: 35px;
        top: 7.5px;
        left: 7.5px;
    }
    
    .spinner-ring:nth-child(3) {
        width: 20px;
        height: 20px;
        top: 15px;
        left: 15px;
    }
    
    .loader-progress {
        width: 150px;
        height: 2px;
    }
    
    .loader-text {
        font-size: 0.8rem;
        letter-spacing: 0.3px;
        line-height: 1.4;
    }
}

/* Mobile Small (320px to 375px) */
@media (max-width: 375px) {
    .loader-container {
        gap: 12px;
        padding: 5px;
        max-width: 95%;
    }
    
    .loader-logo {
        font-size: 1.5rem;
        gap: 6px;
        flex-direction: column;
    }
    
    .loader-logo i {
        font-size: 2rem;
    }
    
    .loader-subtitle {
        font-size: 0.8rem;
        letter-spacing: 0.5px;
        margin-bottom: 5px;
    }
    
    .loader-spinner {
        width: 45px;
        height: 45px;
    }
    
    .spinner-ring:nth-child(1) {
        width: 45px;
        height: 45px;
        border-width: 2px;
    }
    
    .spinner-ring:nth-child(2) {
        width: 30px;
        height: 30px;
        top: 7.5px;
        left: 7.5px;
        border-width: 2px;
    }
    
    .spinner-ring:nth-child(3) {
        width: 15px;
        height: 15px;
        top: 15px;
        left: 15px;
        border-width: 2px;
    }
    
    .loader-progress {
        width: 120px;
        height: 2px;
    }
    
    .loader-text {
        font-size: 0.75rem;
        letter-spacing: 0.2px;
        line-height: 1.3;
        padding: 0 10px;
    }
    
    .loader-particles .loader-particle {
        display: none; /* Hide particles on very small screens for performance */
    }
}

/* Extra Small Mobile (below 320px) */
@media (max-width: 319px) {
    .loader-container {
        gap: 10px;
        padding: 3px;
        max-width: 98%;
    }
    
    .loader-logo {
        font-size: 1.3rem;
        gap: 4px;
        flex-direction: column;
    }
    
    .loader-logo i {
        font-size: 1.8rem;
    }
    
    .loader-subtitle {
        font-size: 0.7rem;
        letter-spacing: 0.3px;
        margin-bottom: 3px;
    }
    
    .loader-spinner {
        width: 40px;
        height: 40px;
    }
    
    .spinner-ring:nth-child(1) {
        width: 40px;
        height: 40px;
        border-width: 2px;
    }
    
    .spinner-ring:nth-child(2) {
        width: 28px;
        height: 28px;
        top: 6px;
        left: 6px;
        border-width: 2px;
    }
    
    .spinner-ring:nth-child(3) {
        width: 16px;
        height: 16px;
        top: 12px;
        left: 12px;
        border-width: 2px;
    }
    
    .loader-progress {
        width: 100px;
        height: 2px;
    }
    
    .loader-text {
        font-size: 0.7rem;
        letter-spacing: 0.1px;
        line-height: 1.2;
        padding: 0 5px;
        text-align: center;
    }
    
    .loader-particles .loader-particle {
        display: none;
    }
}

/* ==========================================
   HIGH DPI / RETINA DISPLAYS
   ========================================== */

@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
    .loader-logo {
        text-shadow: 0 0 30px rgba(0, 212, 255, 0.6), 0 0 60px rgba(0, 212, 255, 0.3);
    }
    
    .progress-bar {
        box-shadow: 0 0 10px rgba(0, 212, 255, 0.5), 0 0 20px rgba(0, 212, 255, 0.2);
    }
    
    .spinner-ring {
        border-width: 3px;
    }
    
    @media (max-width: 375px) {
        .spinner-ring {
            border-width: 2px;
        }
    }
}

/* ==========================================
   LANDSCAPE ORIENTATION ADJUSTMENTS
   ========================================== */

@media (orientation: landscape) and (max-height: 600px) {
    .loader-container {
        gap: 15px;
        padding: 10px;
    }
    
    .loader-logo {
        font-size: 2rem;
        margin-bottom: 0;
    }
    
    .loader-logo i {
        font-size: 2.2rem;
    }
    
    .loader-subtitle {
        font-size: 0.9rem;
        margin-bottom: 5px;
    }
    
    .loader-spinner {
        width: 50px;
        height: 50px;
    }
    
    .spinner-ring:nth-child(1) {
        width: 50px;
        height: 50px;
    }
    
    .spinner-ring:nth-child(2) {
        width: 35px;
        height: 35px;
        top: 7.5px;
        left: 7.5px;
    }
    
    .spinner-ring:nth-child(3) {
        width: 20px;
        height: 20px;
        top: 15px;
        left: 15px;
    }
    
    .loader-text {
        font-size: 0.8rem;
    }
    
    .loader-progress {
        width: 180px;
        height: 3px;
    }
}

/* ==========================================
   DARK MODE SUPPORT (if needed)
   ========================================== */

@media (prefers-color-scheme: dark) {
    /* Already optimized for dark theme */
}

/* ==========================================
   REDUCED MOTION SUPPORT
   ========================================== */

@media (prefers-reduced-motion: reduce) {
    #page-loader::before,
    .loader-logo,
    .loader-logo i,
    .loader-subtitle,
    .loader-text,
    .progress-bar,
    .loader-particle {
        animation: none;
    }
    
    .spinner-ring {
        animation: spin 4s linear infinite;
    }
    
    .progress-bar {
        animation: progressLoad 2s ease-in-out forwards;
    }
}

/* ==========================================
   PERFORMANCE OPTIMIZATIONS
   ========================================== */

/* GPU acceleration for smooth animations */
#page-loader,
.loader-container,
.loader-logo,
.loader-spinner,
.spinner-ring,
.progress-bar,
.loader-particle {
    will-change: transform, opacity;
    transform: translateZ(0);
    backface-visibility: hidden;
}

/* Optimize animations for mobile */
@media (max-width: 768px) {
    .loader-particle {
        animation-duration: 12s;
    }
    
    #page-loader::before {
        animation-duration: 6s;
    }
}

/* ==========================================
   ACCESSIBILITY IMPROVEMENTS
   ========================================== */

/* Focus indicators (if interactive elements are added) */
.loader-container *:focus {
    outline: 2px solid #00d4ff;
    outline-offset: 2px;
}

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