:root {
    --bg-color: #e0f7fa;
    --text-color: #0277bd;
    --btn-bg: #0288d1;
    --btn-bg-hover: #0277bd;
    --btn-text: white;
    --table-border: #0277bd;
    --th-bg: #b3e5fc;
    --input-bg: #ffffff;
    --input-text: #000000;
    --input-border: #cccccc;
    --card-bg: rgba(255, 255, 255, 0.7);
}

body.dark-mode {
    --bg-color: #121212;
    --text-color: #e0e0e0;
    --btn-bg: #333333;
    --btn-bg-hover: #555555;
    --btn-text: #ffffff;
    --table-border: #444444;
    --th-bg: #1e1e1e;
    --input-bg: #2a2a2a;
    --input-text: #ffffff;
    --input-border: #444444;
    --card-bg: rgba(30, 30, 30, 0.7);
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    margin: 0;
    padding: 20px;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color 0.3s, color 0.3s;
    display: flex;
    justify-content: center;
}

.container {
    width: 100%;
    max-width: 900px;
    text-align: center;
}

h1 {
    margin-bottom: 30px;
    font-size: 2.5rem;
}

.controls-card {
    background-color: var(--card-bg);
    padding: 20px;
    border-radius: 15px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    margin-bottom: 30px;
    backdrop-filter: blur(5px);
}

.controls {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    justify-content: center;
    align-items: center;
    margin-bottom: 20px;
}

.control-group {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 5px;
}

.control-group label {
    font-size: 0.9rem;
    font-weight: bold;
}

button {
    padding: 12px 24px;
    font-size: 16px;
    cursor: pointer;
    background-color: var(--btn-bg);
    color: var(--btn-text);
    border: none;
    border-radius: 8px;
    transition: transform 0.2s, background-color 0.3s;
    margin: 5px;
    font-weight: bold;
}

button:hover {
    background-color: var(--btn-bg-hover);
    transform: translateY(-2px);
}

button:active {
    transform: translateY(0);
}

input {
    padding: 8px 12px;
    font-size: 16px;
    background-color: var(--input-bg);
    color: var(--input-text);
    border: 1px solid var(--input-border);
    border-radius: 6px;
    outline: none;
    text-align: center;
}

#minSum,
#maxSum,
#excludeNumbers,
#includeNumbers {
    width: 80px;
}

.range-container {
    margin: 20px 0;
    padding: 15px;
    border-top: 1px solid var(--input-border);
}

.range-options {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
    margin-top: 10px;
}

.range-options label {
    cursor: pointer;
    padding: 5px 10px;
    background-color: var(--input-bg);
    border: 1px solid var(--input-border);
    border-radius: 20px;
    transition: all 0.2s;
}

.range-options label:has(input:checked) {
    background-color: var(--btn-bg);
    color: var(--btn-text);
    border-color: var(--btn-bg);
}

.range-options input {
    display: none;
}

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

.table-wrapper {
    width: 100%;
    overflow-x: auto;
    margin-top: 30px;
    border-radius: 10px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.05);
}

table {
    width: 100%;
    border-collapse: collapse;
    background-color: var(--card-bg);
}

th,
td {
    border-bottom: 1px solid var(--table-border);
    padding: 15px 10px;
    text-align: center;
}

th {
    background-color: var(--th-bg);
    font-weight: bold;
}

.theme-toggle-btn {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1000;
    margin: 0;
    padding: 8px 15px;
    font-size: 14px;
    opacity: 0.9;
}

.circle {
    display: inline-block;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    line-height: 32px;
    color: white;
    font-weight: bold;
    text-align: center;
    margin: 3px;
    font-size: 14px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
}

.range-0 { background-color: #fbc02d; } /* 0번대: 노랑 */
.range-10 { background-color: #1976d2; } /* 10번대: 파랑 */
.range-20 { background-color: #d32f2f; } /* 20번대: 빨강 */
.range-30 { background-color: #757575; } /* 30번대: 회색 */
.range-40 { background-color: #388e3c; } /* 40번대: 초록 */

/* Media Queries */
@media (max-width: 600px) {
    h1 { font-size: 1.8rem; }
    .theme-toggle-btn { top: 10px; right: 10px; padding: 5px 10px; font-size: 12px; }
    .controls { gap: 10px; }
    .circle { width: 28px; height: 28px; line-height: 28px; font-size: 12px; margin: 2px; }
    th, td { padding: 10px 5px; font-size: 14px; }
    button { width: 100%; max-width: 250px; }
}