* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Poppins', sans-serif;
}

body {
    background: linear-gradient(135deg, #0f2027, #203a43, #2c5364);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    color: #ffffff;
    overflow: hidden;
}

/* Glassmorphism Container */
.app-container {
    width: 90%;
    max-width: 500px;
    background: rgba(255, 255, 255, 0.05);
    backdrop-filter: blur(15px);
    -webkit-backdrop-filter: blur(15px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 24px;
    padding: 40px 30px;
    box-shadow: 0 25px 50px rgba(0, 0, 0, 0.5);
    position: relative;
    overflow: hidden;
}

/* Screen Management */
.screen {
    display: none;
    flex-direction: column;
    align-items: center;
    text-align: center;
    animation: fadeIn 0.5s ease-in-out;
}

.screen.active {
    display: flex;
}

.screen.hidden {
    display: none;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Start Screen */
.icon-container {
    font-size: 4rem;
    color: #4facfe;
    margin-bottom: 20px;
    text-shadow: 0 0 20px rgba(79, 172, 254, 0.5);
}

h1 {
    font-size: 2.2rem;
    font-weight: 700;
    margin-bottom: 10px;
    background: linear-gradient(to right, #4facfe 0%, #00f2fe 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

p {
    font-size: 1rem;
    color: rgba(255, 255, 255, 0.7);
    margin-bottom: 30px;
}

/* Buttons */
.btn {
    border: none;
    padding: 15px 30px;
    font-size: 1.1rem;
    font-weight: 600;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    width: 100%;
}

.primary-btn {
    background: linear-gradient(to right, #4facfe 0%, #00f2fe 100%);
    color: #0f2027;
    box-shadow: 0 10px 20px rgba(79, 172, 254, 0.3);
}

.primary-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 25px rgba(79, 172, 254, 0.4);
}

.primary-btn:active {
    transform: translateY(1px);
}

/* Quiz Screen */
.header {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
}

.progress-container {
    flex: 1;
    text-align: left;
}

#question-counter {
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.8);
    font-weight: 600;
}

.progress-bar {
    width: 90%;
    height: 8px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 10px;
    margin-top: 5px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(to right, #4facfe, #00f2fe);
    width: 0%;
    transition: width 0.3s ease;
}

.timer-container {
    background: rgba(255, 255, 255, 0.1);
    padding: 8px 15px;
    border-radius: 20px;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 8px;
    color: #ff6b6b;
    box-shadow: 0 0 15px rgba(255, 107, 107, 0.2);
}

.timer-warning {
    animation: pulse 1s infinite;
}

@keyframes pulse {
    0% { transform: scale(1); box-shadow: 0 0 15px rgba(255, 107, 107, 0.2); }
    50% { transform: scale(1.05); box-shadow: 0 0 25px rgba(255, 107, 107, 0.6); }
    100% { transform: scale(1); box-shadow: 0 0 15px rgba(255, 107, 107, 0.2); }
}

.question-container {
    width: 100%;
    margin-bottom: 30px;
    text-align: left;
}

#question-text {
    font-size: 1.4rem;
    font-weight: 600;
    line-height: 1.4;
}

.options-container {
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.option-btn {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: white;
    padding: 15px 20px;
    border-radius: 15px;
    font-size: 1rem;
    text-align: left;
    cursor: pointer;
    transition: all 0.2s ease;
}

.option-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    transform: translateX(5px);
    border-color: rgba(255, 255, 255, 0.3);
}

.option-btn.correct {
    background: rgba(46, 204, 113, 0.2);
    border-color: #2ecc71;
    color: #2ecc71;
}

.option-btn.wrong {
    background: rgba(231, 76, 60, 0.2);
    border-color: #e74c3c;
    color: #e74c3c;
}

.option-btn:disabled {
    cursor: not-allowed;
    opacity: 0.8;
}

/* Result Screen */
.result-icon {
    font-size: 5rem;
    color: #f1c40f;
    text-shadow: 0 0 30px rgba(241, 196, 15, 0.4);
    animation: bounce 2s infinite;
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translateY(0); }
    40% { transform: translateY(-20px); }
    60% { transform: translateY(-10px); }
}

.score-container {
    background: rgba(0, 0, 0, 0.2);
    border-radius: 20px;
    padding: 20px;
    margin: 20px 0;
    width: 100%;
}

.score-container p {
    margin-bottom: 5px;
}

#score-text {
    font-size: 3rem;
    font-weight: 700;
    color: #4facfe;
}

.action-buttons {
    width: 100%;
    margin-top: 10px;
}

/* Responsive */
@media (max-width: 400px) {
    .app-container {
        padding: 30px 20px;
    }
    
    h1 {
        font-size: 1.8rem;
    }
    
    #question-text {
        font-size: 1.2rem;
    }
}