* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    background-attachment: fixed;
    color: #333;
    line-height: 1.6;
    overflow-x: hidden;
}

body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background:
        radial-gradient(circle at 20% 50%, rgba(120, 255, 214, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(255, 107, 107, 0.1) 0%, transparent 50%),
        linear-gradient(135deg, #e8f5e9 0%, #c8e6c9 100%);
    z-index: -1;
    opacity: 0.3;
}

.header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
    padding: 2rem 1rem;
    text-align: center;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    position: relative;
    overflow: hidden;
    animation: headerGlow 3s ease-in-out infinite;
}

@keyframes headerGlow {
    0%, 100% {
        box-shadow: 0 10px 30px rgba(102, 126, 234, 0.3);
    }
    50% {
        box-shadow: 0 10px 40px rgba(240, 147, 251, 0.5);
    }
}

.header::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, transparent 70%);
    animation: rotate 20s linear infinite;
}

@keyframes rotate {
    from {
        transform: rotate(0deg);
    }
    to {
        transform: rotate(360deg);
    }
}

.header-content {
    position: relative;
    z-index: 1;
}

.header-left {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 0.5rem;
}

.header-left i {
    font-size: 2.5rem;
    color: #fff;
    animation: bookFlip 2s ease-in-out infinite;
}

@keyframes bookFlip {
    0%, 100% {
        transform: rotateY(0deg);
    }
    50% {
        transform: rotateY(180deg);
    }
}

.header h1 {
    font-size: 3rem;
    color: #fff;
    text-shadow: 2px 2px 10px rgba(0, 0, 0, 0.3);
    letter-spacing: 2px;
}

.header-description {
    color: rgba(255, 255, 255, 0.9);
    font-size: 1.2rem;
    margin-bottom: 1.5rem;
}

.header-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.nav-link {
    padding: 0.75rem 1.5rem;
    background: rgba(255, 255, 255, 0.2);
    color: #fff;
    text-decoration: none;
    border-radius: 30px;
    backdrop-filter: blur(10px);
    border: 2px solid rgba(255, 255, 255, 0.3);
    transition: all 0.3s ease;
    font-weight: 600;
}

.nav-link:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

.quiz-generator-btn {
    padding: 0.75rem 1.5rem;
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    color: #fff;
    border: none;
    border-radius: 30px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 5px 15px rgba(245, 87, 108, 0.3);
    position: relative;
    overflow: hidden;
}

.quiz-generator-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    transition: left 0.5s ease;
}

.quiz-generator-btn:hover::before {
    left: 100%;
}

.quiz-generator-btn:hover {
    transform: translateY(-3px) scale(1.05);
    box-shadow: 0 8px 20px rgba(245, 87, 108, 0.4);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem 1rem;
}

.neumorphic {
    background: rgba(255, 255, 255, 0.9);
    border-radius: 20px;
    box-shadow:
        8px 8px 16px rgba(0, 0, 0, 0.1),
        -8px -8px 16px rgba(255, 255, 255, 0.7);
    padding: 2rem;
    transition: all 0.3s ease;
}

.neumorphic:hover {
    box-shadow:
        12px 12px 24px rgba(0, 0, 0, 0.15),
        -12px -12px 24px rgba(255, 255, 255, 0.8);
    transform: translateY(-5px);
}

.upload-section {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.upload-card h2,
.timer-section h2 {
    color: #667eea;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.upload-area {
    border: 3px dashed #667eea;
    border-radius: 15px;
    padding: 2rem;
    text-align: center;
    transition: all 0.3s ease;
    cursor: pointer;
}

.upload-area:hover {
    border-color: #764ba2;
    background: rgba(102, 126, 234, 0.05);
    transform: scale(1.02);
}

.upload-icon {
    font-size: 4rem;
    color: #667eea;
    margin-bottom: 1rem;
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-10px);
    }
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #fff;
    border: none;
    padding: 0.75rem 2rem;
    border-radius: 30px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.3);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(102, 126, 234, 0.4);
}

.timer-controls {
    display: flex;
    gap: 1rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

#timerInput {
    flex: 1;
    min-width: 100px;
    padding: 0.75rem;
    border: 2px solid #667eea;
    border-radius: 15px;
    font-size: 1rem;
    transition: all 0.3s ease;
    background: rgba(255, 255, 255, 0.9);
}

#timerInput:focus {
    outline: none;
    border-color: #764ba2;
    box-shadow: 0 0 10px rgba(102, 126, 234, 0.3);
}

.btn-start {
    background: linear-gradient(135deg, #11998e 0%, #38ef7d 100%);
    color: #fff;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 30px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 5px 15px rgba(56, 239, 125, 0.3);
}

.btn-start:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(56, 239, 125, 0.4);
}

.btn-stop {
    background: linear-gradient(135deg, #ff6b6b 0%, #ee5a6f 100%);
    color: #fff;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 30px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 5px 15px rgba(255, 107, 107, 0.3);
}

.btn-stop:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(255, 107, 107, 0.4);
}

.btn-focus {
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    color: #fff;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 30px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 5px 15px rgba(240, 147, 251, 0.3);
    width: 100%;
    margin-top: 1rem;
}

.btn-focus:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(240, 147, 251, 0.4);
}

.focus-status {
    margin-top: 1rem;
    padding: 0.75rem;
    background: linear-gradient(135deg, #ffeaa7 0%, #fdcb6e 100%);
    border-radius: 10px;
    text-align: center;
    font-weight: 600;
    color: #2d3436;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
}

.timer-display {
    text-align: center;
    margin: 1.5rem 0;
}

.time-remaining {
    font-size: 3rem;
    font-weight: 700;
    color: #667eea;
    margin-bottom: 1rem;
}

.progress-ring {
    display: inline-block;
    position: relative;
}

.progress-ring-circle {
    fill: none;
    stroke: #e0e0e0;
    stroke-width: 8;
}

.progress-ring-bar {
    fill: none;
    stroke: #667eea;
    stroke-width: 8;
    stroke-linecap: round;
    transform: rotate(-90deg);
    transform-origin: 50% 50%;
    transition: stroke-dashoffset 1s linear;
}

.pdf-viewer-section {
    margin: 2rem 0;
}

.viewer-controls {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
}

.btn-control {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #fff;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 30px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.3);
}

.btn-control:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(102, 126, 234, 0.4);
}

.pdf-viewer {
    width: 100%;
    height: 600px;
    border: none;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

.stats-section {
    margin: 3rem 0;
}

.glowing-stats {
    position: relative;
    animation: glowPulse 3s ease-in-out infinite;
}

@keyframes glowPulse {
    0%, 100% {
        box-shadow:
            8px 8px 16px rgba(0, 0, 0, 0.1),
            -8px -8px 16px rgba(255, 255, 255, 0.7),
            0 0 20px rgba(255, 215, 0, 0.3);
    }
    50% {
        box-shadow:
            12px 12px 24px rgba(0, 0, 0, 0.15),
            -12px -12px 24px rgba(255, 255, 255, 0.8),
            0 0 40px rgba(255, 140, 0, 0.5),
            0 0 60px rgba(255, 69, 0, 0.3);
    }
}

.stats-card h2 {
    color: #f5576c;
    margin-bottom: 2rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 2rem;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
}

.stat-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1.5rem;
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.1) 0%, rgba(118, 75, 162, 0.1) 100%);
    border-radius: 15px;
    transition: all 0.3s ease;
}

.stat-item:hover {
    transform: translateY(-5px);
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.2) 0%, rgba(118, 75, 162, 0.2) 100%);
}

.stat-icon {
    font-size: 2.5rem;
    color: #667eea;
}

.stat-content {
    display: flex;
    flex-direction: column;
}

.stat-value {
    font-size: 2.5rem;
    font-weight: 700;
    color: #333;
}

.stat-label {
    font-size: 0.9rem;
    color: #666;
}

.resources-section {
    margin: 3rem 0;
}

.section-title {
    text-align: center;
    color: #fff;
    font-size: 2.5rem;
    margin-bottom: 2rem;
    text-shadow: 2px 2px 10px rgba(0, 0, 0, 0.3);
}

.resources-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.resource-card {
    text-align: center;
    padding: 2rem;
    transition: all 0.3s ease;
    cursor: pointer;
}

.resource-card:hover {
    transform: translateY(-10px) scale(1.05);
}

.resource-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 1rem;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    animation: iconRotate 3s ease-in-out infinite;
}

@keyframes iconRotate {
    0%, 100% {
        transform: rotate(0deg);
    }
    50% {
        transform: rotate(180deg);
    }
}

.resource-icon i {
    font-size: 2.5rem;
    color: #fff;
}

.resource-card h3 {
    color: #667eea;
    margin-bottom: 0.5rem;
}

.resource-card p {
    color: #666;
}

.popup-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    backdrop-filter: blur(5px);
}

.popup {
    text-align: center;
    max-width: 400px;
    animation: popupSlideIn 0.5s ease;
}

@keyframes popupSlideIn {
    from {
        transform: scale(0.7) translateY(-50px);
        opacity: 0;
    }
    to {
        transform: scale(1) translateY(0);
        opacity: 1;
    }
}

.popup-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 1rem;
    background: linear-gradient(135deg, #11998e 0%, #38ef7d 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    animation: checkBounce 0.6s ease;
}

@keyframes checkBounce {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.2);
    }
}

.popup-icon i {
    font-size: 3rem;
    color: #fff;
}

.popup h2 {
    color: #333;
    margin-bottom: 1rem;
}

.popup p {
    color: #666;
    margin-bottom: 1.5rem;
}

.hidden {
    display: none !important;
}

.file-info {
    margin-top: 1rem;
    padding: 1rem;
    background: linear-gradient(135deg, rgba(56, 239, 125, 0.1) 0%, rgba(17, 153, 142, 0.1) 100%);
    border-radius: 10px;
    color: #11998e;
    font-weight: 600;
}

.footer {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #fff;
    text-align: center;
    padding: 2rem 1rem;
    margin-top: 3rem;
    box-shadow: 0 -5px 20px rgba(0, 0, 0, 0.2);
}

@media (max-width: 768px) {
    .header h1 {
        font-size: 2rem;
    }

    .header-description {
        font-size: 1rem;
    }

    .upload-section {
        grid-template-columns: 1fr;
    }

    .stats-grid {
        grid-template-columns: 1fr;
    }

    .resources-grid {
        grid-template-columns: 1fr;
    }

    .time-remaining {
        font-size: 2rem;
    }

    .stat-value {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    .timer-controls {
        flex-direction: column;
    }

    .viewer-controls {
        flex-direction: column;
    }

    .header-buttons {
        flex-direction: column;
        width: 100%;
    }

    .nav-link,
    .quiz-generator-btn {
        width: 100%;
    }
}