* {
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    box-sizing: border-box;
}

body {
    background-color: #e6e9f0;
    background-image: 
        linear-gradient(rgba(255,255,255,0.8) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255,255,255,0.8) 1px, transparent 1px),
        linear-gradient(rgba(255,255,255,0.3) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255,255,255,0.3) 1px, transparent 1px);
    background-size: 
        100px 100px,
        100px 100px,
        20px 20px,
        20px 20px;
    background-position:
        -1px -1px,
        -1px -1px,
        -1px -1px,
        -1px -1px;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.app {
    background: rgba(255, 255, 255, 0.95);
    width: 90%;
    max-width: 600px;
    margin: 50px auto;
    border-radius: 10px;
    padding: 30px;
    text-align: center;
    box-shadow: 0 10px 25px rgba(0, 30, 77, 0.2);
    border: 1px solid #d6dce5;
    position: relative;
    overflow: hidden;
}

.app::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 5px;
    background: linear-gradient(90deg, #217346, #26c281);
}

.app h1 {
    font-size: 30px;
    color: #217346;
    font-weight: 600;
    border-bottom: 1px solid #d6dce5;
    padding-bottom: 30px;
    margin-bottom: 20px;
}

.welcome-content p {
    font-size: 18px;
    color: #4a5568;
    margin: 20px 0;
    line-height: 1.6;
}

.btn {
    background: #217346;
    color: #fff;
    font-weight: 500;
    width: 150px;
    border: none;
    padding: 12px;
    margin: 10px auto;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.3s;
    font-size: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.btn:hover {
    background: #1a5c38;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.quiz {
    padding: 20px 0;
}

#answer-buttons {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin: 25px 0;
}

#answer-buttons .btn {
    width: 100%;
    text-align: left;
    background: #f7fafc;
    color: #2d3748;
    border: 1px solid #e2e8f0;
    padding: 12px 20px;
    transition: all 0.2s;
}

#answer-buttons .btn:hover:not([disabled]) {
    background: #edf2f7;
    color: #2d3748;
    transform: translateY(0);
    box-shadow: none;
    border-color: #cbd5e0;
}

.next-btn {
    background: #217346;
    color: #fff;
    padding: 12px 30px;
    margin: 20px auto 0;
    display: none;
    border-radius: 6px;
    font-weight: 500;
    transition: all 0.3s;
}

.next-btn:hover {
    background: #1a5c38;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.correct {
    background: #9aeabc !important;
    border-color: #48bb78 !important;
    color: #22543d !important;
    animation: pulseCorrect 0.5s ease;
}

.incorrect {
    background: #ff9393 !important;
    border-color: #f56565 !important;
    color: #742a2a !important;
    animation: shakeWrong 0.5s ease;
}

.fas {
    color: inherit;
}

@keyframes pulseCorrect {
    0% { transform: scale(1); }
    50% { transform: scale(1.03); }
    100% { transform: scale(1); }
}

@keyframes shakeWrong {
    0%, 100% { transform: translateX(0); }
    20%, 60% { transform: translateX(-3px); }
    40%, 80% { transform: translateX(3px); }
}

.question-transition {
    animation: fadeIn 0.5s;
}

.score-reveal {
    animation: bounceIn 1s;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes bounceIn {
    0% { transform: scale(0.9); opacity: 0; }
    60% { transform: scale(1.05); opacity: 1; }
    100% { transform: scale(1); }
}

.excel-cell {
    position: absolute;
    background: rgba(255, 255, 255, 0.7);
    border: 1px solid #e2e8f0;
    border-radius: 4px;
    padding: 2px 5px;
    font-size: 12px;
    color: #4a5568;
    pointer-events: none;
}