body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    height: 100vh;
    display: flex;
    flex-direction: column;
    background-color: #f4f6f8;
    transition: background-color 0.3s;
}

/* 탭 버튼 */
.tab-buttons {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    display: flex;
    justify-content: center;
    background-color: #f1f1f1;
    padding: 10px 0;
    gap: 10px;
    box-shadow: 0 2px 6px rgba(0,0,0,0.2);
    z-index: 1000;
}
.tab-buttons button {
    padding: 8px 15px;
    font-size: 16px;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    background-color: #007BFF;
    color: white;
    transition: background-color 0.3s;
}
.tab-buttons button:hover {
    background-color: #0056b3;
}

/* 각 탭 컨테이너 */
.container {
    position: absolute;
    top: 50px; /* 탭 버튼 아래 */
    left: 0;
    width: 100%;
    height: calc(100vh - 50px);
    overflow-y: auto;
    padding: 20px;
    box-sizing: border-box;
}

/* 카드 래퍼 */
.cards-wrapper {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    justify-content: center;
}

/* 카드 기본 스타일 */
.card {
    background-color: #fff;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    padding: 20px;
    flex: 1;
    min-width: 300px;
    display: flex;
    flex-direction: column;
    align-items: center;
    transition: all 0.3s ease;
}

/* 입력창, 버튼 */
.card input[type="text"], .card input[type="number"] {
    width: 80%;
    padding: 10px;
    margin: 8px 0;
    border-radius: 8px;
    border: 1px solid #ccc;
    font-size: 16px;
}
.card button {
    padding: 10px 20px;
    margin: 5px;
    border-radius: 8px;
    background-color: #007bff;
    color: white;
    cursor: pointer;
    font-weight: 600;
    transition: background-color 0.3s;
}
.card button:hover {
    background-color: #0056b3;
}

/* 결과 박스 */
.result {
    width: 90%;
    margin-top: 15px;
    padding: 10px;
    border-radius: 8px;
    background-color: #f0f8ff;
    font-family: monospace;
    min-height: 40px;
}

/* 테마 박스 */
.theme-boxes {
    display: flex;
    gap: 10px;
    margin-top: 10px;
}
.theme-square {
    width: 40px;
    height: 40px;
    cursor: pointer;
    border-radius: 6px;
    transition: transform 0.2s;
}
.theme-square:hover {
    transform: scale(1.1);
}

/* 숨김 처리 */
.hidden {
    display: none;
}
footer {
    position: fixed;   /* 항상 화면 아래 고정 */
    bottom: 0;
    left: 0;
    width: 100%;
    background-color: #f1f1f1;
    text-align: center;
    padding: 10px 0;
    box-shadow: 0 -2px 6px rgba(0,0,0,0.1);
    z-index: 1001;     /* 탭 버튼보다 위에 나타나게 */
}
.num-pad {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 5px;
    margin-top: 10px;
}
.num-pad button {
    padding: 15px;
    font-size: 18px;
    border-radius: 6px;
    background-color: #4a90e2;
    color: white;
    border: none;
    cursor: pointer;
}
.num-pad button:hover {
    background-color: #357ABD;
}


/* 반응형 */
@media (max-width: 700px) {
    .cards-wrapper {
        flex-direction: column;
        align-items: center;
    }
}