/* CSS tùy chỉnh cho numpad buttons */

/* Class chung cho tất cả button số */
.num-btn {
    /* Kích thước cơ bản - tối ưu mobile */
    width: 70px;
    height: 70px;
    font-size: 25px;
    font-weight: bold;
    border-radius: 50%;
    border: 2px solid #e94057;
    background: rgba(255, 255, 255, 0.95);
    color: #e94057;
    cursor: pointer;
    transition: all 0.2s ease;
    margin: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 3px 10px rgba(0, 0, 0, 0.15);
    backdrop-filter: blur(5px);
}

/* Hiệu ứng đặc biệt cho từng số - hiện rõ nét luôn */
.num-1 {
    background: linear-gradient(135deg, #ff6b6b, #ee5a24);
    color: #E84C86;
    border-color: rgba(255, 255, 255, 0.3);
    box-shadow: 0 4px 15px rgba(255, 107, 107, 0.4);
}

.num-2 {
    background: linear-gradient(135deg, #feca57, #ff9ff3);
    color: #E84C86;
    border-color: rgba(255, 255, 255, 0.3);
    box-shadow: 0 4px 15px rgba(254, 202, 87, 0.4);
}

.num-3 {
    background: linear-gradient(135deg, #48dbfb, #0abde3);
    color: #E84C86;
    border-color: rgba(255, 255, 255, 0.3);
    box-shadow: 0 4px 15px rgba(72, 219, 251, 0.4);
}

.num-4 {
    background: linear-gradient(135deg, #1dd1a1, #10ac84);
    color: #E84C86;
    border-color: rgba(255, 255, 255, 0.3);
    box-shadow: 0 4px 15px rgba(29, 209, 161, 0.4);
}

.num-5 {
    background: linear-gradient(135deg, #ff9ff3, #f368e0);
    color: #E84C86;
    border-color: rgba(255, 255, 255, 0.3);
    box-shadow: 0 4px 15px rgba(255, 159, 243, 0.4);
}

.num-6 {
    background: linear-gradient(135deg, #54a0ff, #2e86de);
    color: #E84C86;
    border-color: rgba(255, 255, 255, 0.3);
    box-shadow: 0 4px 15px rgba(84, 160, 255, 0.4);
}

.num-7 {
    background: linear-gradient(135deg, #5f27cd, #341f97);
    color: #E84C86;
    border-color: rgba(255, 255, 255, 0.3);
    box-shadow: 0 4px 15px rgba(95, 39, 205, 0.4);
}

.num-8 {
    background: linear-gradient(135deg, #00d2d3, #54a0ff);
    color: #E84C86;
    border-color: rgba(255, 255, 255, 0.3);
    box-shadow: 0 4px 15px rgba(0, 210, 211, 0.4);
}

.num-9 {
    background: linear-gradient(135deg, #ff9f43, #ee5a24);
    color: #E84C86;
    border-color: rgba(255, 255, 255, 0.3);
    box-shadow: 0 4px 15px rgba(255, 159, 67, 0.4);
}

/* Các button khác */
.num-0 {
    background: linear-gradient(135deg, #e84393, #fd79a8);
    color: #E84C86;
    border-color: rgba(255, 255, 255, 0.3);
    box-shadow: 0 4px 15px rgba(232, 67, 147, 0.4);
}

.num-star {
    background: linear-gradient(135deg, #6c5ce7, #a29bfe);
    color: #E84C86;
    border-color: rgba(255, 255, 255, 0.3);
    box-shadow: 0 4px 15px rgba(108, 92, 231, 0.4);
}

.num-backspace {
    background: linear-gradient(135deg, #e17055, #d63031);
    color: #E84C86;
    border-color: rgba(255, 255, 255, 0.3);
    box-shadow: 0 4px 15px rgba(225, 112, 85, 0.4);
}

/* Hover effect - nhẹ nhàng hơn */
.num-btn:hover {
    transform: scale(1.05);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.25);
}

/* Active effect khi click */
.num-btn:active {
    transform: scale(0.98);
    transition: transform 0.1s ease;
}

/* Responsive design - tối ưu mobile */
@media (max-width: 768px) {
    .num-btn {
        width: 65px;
        height: 65px;
        font-size: 20px;
        margin: 3px;
        box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
    }

    .num-btn:hover {
        transform: scale(1.03);
    }
}

@media (max-width: 480px) {
    .num-btn {
        width: 55px;
        height: 55px;
        font-size: 18px;
        margin: 2px;
        box-shadow: 0 2px 6px rgba(0, 0, 0, 0.15);
    }

    .num-btn:hover {
        transform: scale(1.02);
    }
}

/* Tối ưu cho màn hình nhỏ */
@media (max-width: 360px) {
    .num-btn {
        width: 50px;
        height: 50px;
        font-size: 16px;
        margin: 1px;
    }
}

/* Hiệu ứng ripple khi click (tùy chọn) */
.num-btn {
    position: relative;
    overflow: hidden;
}

.num-btn::after {
    content: "";
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.3);
    transform: translate(-50%, -50%);
    transition: width 0.3s, height 0.3s;
}

.num-btn:active::after {
    width: 100px;
    height: 100px;
}