* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica', sans-serif;
    background: #f5f7fa;
    padding: 20px;
    min-height: 100vh;
}

.admin-container {
    max-width: 1200px;
    margin: 0 auto;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    padding: 20px;
    background: white;
    border-radius: 15px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.header h1 {
    font-size: 24px;
    color: #333;
}

.back-btn {
    background: #667eea;
    color: white;
    padding: 10px 20px;
    border-radius: 10px;
    text-decoration: none;
    font-size: 14px;
    transition: all 0.3s;
}

.back-btn:hover {
    background: #5a6fd8;
    transform: translateY(-2px);
}

/* 로그인 섹션 */
.login-section {
    max-width: 400px;
    margin: 100px auto;
    padding: 40px;
    background: white;
    border-radius: 15px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.1);
    text-align: center;
}

.login-section h2 {
    margin-bottom: 20px;
    color: #333;
}

.login-section input {
    width: 100%;
    padding: 15px;
    border: 2px solid #ddd;
    border-radius: 10px;
    font-size: 16px;
    margin-bottom: 15px;
    outline: none;
}

.login-section input:focus {
    border-color: #667eea;
}

.login-section button {
    width: 100%;
    padding: 15px;
    background: #667eea;
    color: white;
    border: none;
    border-radius: 10px;
    font-size: 16px;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.3s;
}

.login-section button:hover {
    background: #5a6fd8;
}

.hint {
    margin-top: 15px;
    color: #999;
    font-size: 13px;
}

/* 관리자 패널 */
.admin-panel {
    animation: fadeIn 0.5s;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.chart-container {
    background: white;
    padding: 25px;
    border-radius: 15px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    margin-bottom: 30px;
}

.chart-title {
    font-size: 18px;
    font-weight: bold;
    color: #333;
    margin-bottom: 20px;
    text-align: center;
}

.stat-card {
    background: white;
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    text-align: center;
}

.stat-number {
    font-size: 36px;
    font-weight: bold;
    color: #667eea;
    margin-bottom: 10px;
}

.stat-label {
    color: #666;
    font-size: 14px;
}

.actions {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

.action-btn {
    padding: 12px 20px;
    border: none;
    border-radius: 10px;
    font-size: 14px;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.3s;
}

.action-btn.export {
    background: #10b981;
    color: white;
}

.action-btn.export:hover {
    background: #059669;
}

.action-btn.delete {
    background: #ef4444;
    color: white;
}

.action-btn.delete:hover {
    background: #dc2626;
}

.table-container {
    background: white;
    border-radius: 15px;
    padding: 20px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
}

thead {
    background: #f9fafb;
}

th {
    padding: 15px;
    text-align: left;
    font-weight: 600;
    color: #374151;
    border-bottom: 2px solid #e5e7eb;
}

td {
    padding: 15px;
    border-bottom: 1px solid #e5e7eb;
    color: #6b7280;
}

tbody tr:hover {
    background: #f9fafb;
}

.delete-btn {
    background: #ef4444;
    color: white;
    border: none;
    padding: 6px 12px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 12px;
    transition: all 0.2s;
}

.delete-btn:hover {
    background: #dc2626;
}

.sent-checkbox {
    width: 20px;
    height: 20px;
    cursor: pointer;
    accent-color: #10b981;
}

.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: #9ca3af;
    font-size: 16px;
}

/* 반응형 디자인 */
@media (max-width: 768px) {
    .header {
        flex-direction: column;
        gap: 15px;
        text-align: center;
    }
    
    .actions {
        flex-direction: column;
    }
    
    .action-btn {
        width: 100%;
    }
    
    table {
        font-size: 14px;
    }
    
    th, td {
        padding: 10px;
    }
}