/* --- BỐ CỤC HỘI CHỢ KHOA HỌC --- */
.fair-arena {
    height: 220px;
    background: linear-gradient(180deg, #e1bee7 0%, #ce93d8 100%);
    box-shadow: inset 0 0 20px rgba(0,0,0,0.3);
    position: relative; 
    overflow: hidden;
}

/* Cờ đuôi nheo trang trí */
.fair-bg {
    position: absolute;
    top: 0; left: 0;
    width: 100%; height: 30px;
    background-image: repeating-linear-gradient(
        135deg,
        #ffeb3b 0, #ffeb3b 20px,
        #ff5252 20px, #ff5252 40px,
        #4fc3f7 40px, #4fc3f7 60px
    );
    box-shadow: 0 4px 6px rgba(0,0,0,0.2);
    z-index: 1;
}

/* Gian hàng (Booth) */
.science-booth {
    position: absolute;
    top: 55%; left: 55%;
    transform: translate(-50%, -50%);
    width: 140px; height: 130px;
    background: #fff;
    border: 4px solid #9c27b0;
    border-radius: 5px;
    z-index: 2;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    box-shadow: 0 10px 15px rgba(0,0,0,0.3);
    transition: border-color 0.5s ease;
}

/* Mái che của gian hàng */
.booth-roof {
    width: 110%;
    height: 30px;
    margin-left: -5%;
    background: #9c27b0;
    border-radius: 15px 15px 0 0;
    margin-top: -10px;
    transition: background-color 0.5s ease;
}

/* Mặt bàn trưng bày */
.booth-counter {
    width: 100%; height: 50px;
    background: #f5f5f5;
    border-top: 3px solid #ccc;
    display: flex;
    justify-content: center;
    align-items: flex-end;
    padding-bottom: 5px;
}

/* Đồ vật trên bàn */
.booth-item {
    font-size: 3rem;
    filter: drop-shadow(0 4px 4px rgba(0,0,0,0.4));
}

/* Hiệu ứng khi trả lời đúng */
.glow-success {
    animation: flash-item 1s ease-out forwards;
}
@keyframes flash-item {
    0%, 100% { filter: drop-shadow(0 4px 4px rgba(0,0,0,0.4)) scale(1); }
    50% { filter: drop-shadow(0 0 20px #ffeb3b) scale(1.2); }
}

/* Nhân vật Học sinh */
.student-char {
    position: absolute;
    bottom: 20px;
    left: 10%;
    font-size: 4rem;
    z-index: 5;
    filter: drop-shadow(3px 5px 4px rgba(0,0,0,0.5));
}

/* Nhảy mừng */
.happy-jump {
    animation: build-jump 0.8s ease-out forwards !important;
}
@keyframes build-jump {
    0% { transform: translateY(0); }
    50% { transform: translateY(-30px) scale(1.1); }
    100% { transform: translateY(0); }
}

/* Rung lắc khi sai */
.shake-error { animation: shake-char 0.4s !important; }
@keyframes shake-char {
    0% { transform: translateX(0); }
    25% { transform: translateX(-15px) rotate(-10deg); }
    50% { transform: translateX(15px) rotate(10deg); }
    75% { transform: translateX(-15px) rotate(-10deg); }
    100% { transform: translateX(0); }
}

.min-h-75 { min-height: 85px; }