/* Common Styles - Modern and Professional */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Noto Sans KR', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8f9fa;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Button Styles */
.btn {
    display: inline-block;
    padding: 12px 24px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-decoration: none;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 16px;
    font-weight: 500;
    transition: all 0.3s ease;
    text-align: center;
    min-width: 120px;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.btn-secondary {
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
}

.btn-success {
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
}

.btn-social {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    padding: 12px;
    margin: 8px 0;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
}

.btn-social:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.btn-google {
    background: #fff;
    color: #333;
    border: 1px solid #ddd;
}

.btn-kakao {
    background: #fee500;
    color: #333;
}

.btn-naver {
    background: #03c75a;
    color: white;
}

/* Form Styles */
.form-group {
    margin-bottom: 20px;
}

.form-label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: #555;
}

.form-input {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid #e9ecef;
    border-radius: 8px;
    font-size: 16px;
    transition: border-color 0.3s ease;
    background: white;
}

.form-input:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

/* Card Styles */
.card {
    background: white;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    padding: 30px;
    margin: 20px 0;
}

/* Header Styles */
.header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 20px 0;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 24px;
    font-weight: bold;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-links a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: opacity 0.3s ease;
}

.nav-links a:hover {
    opacity: 0.8;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 0 15px;
    }

    .card {
        padding: 20px;
        margin: 15px 0;
    }

    .nav {
        flex-direction: column;
        gap: 15px;
    }

    .nav-links {
        gap: 20px;
    }
}

/* Utility Classes */
.text-center {
    text-align: center;
}

.text-left {
    text-align: left;
}

.text-right {
    text-align: right;
}

.mt-1 { margin-top: 0.25rem; }
.mt-2 { margin-top: 0.5rem; }
.mt-3 { margin-top: 1rem; }
.mt-4 { margin-top: 1.5rem; }
.mt-5 { margin-top: 3rem; }

.mb-1 { margin-bottom: 0.25rem; }
.mb-2 { margin-bottom: 0.5rem; }
.mb-3 { margin-bottom: 1rem; }
.mb-4 { margin-bottom: 1.5rem; }
.mb-5 { margin-bottom: 3rem; }

.p-1 { padding: 0.25rem; }
.p-2 { padding: 0.5rem; }
.p-3 { padding: 1rem; }
.p-4 { padding: 1.5rem; }
.p-5 { padding: 3rem; }

/* Loading Spinner */
.spinner {
    border: 4px solid #f3f3f3;
    border-top: 4px solid #667eea;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
    margin: 20px auto;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}