/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #fff;
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.clearfix::after {
    content: "";
    display: table;
    clear: both;
}

/* Header */
header {
    background-color: #f8f8f8;
    padding: 15px 0;
    border-bottom: 1px solid #e7e7e7;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

.logo {
    float: left;
    font-size: 24px;
    font-weight: 600;
    padding: 10px 0;
    letter-spacing: -0.5px;
}

.logo a {
    text-decoration: none;
    color: #333;
    transition: color 0.2s ease;
}

.logo .red {
    color: #d63031;
}

/* User Info */
#user-info {
    float: right;
    padding: 15px 0;
    font-size: 14px;
    font-weight: 500;
}

#user-info a {
    color: #333;
    text-decoration: none;
    transition: color 0.2s ease;
}

#user-info a:hover {
    color: #d63031;
}

/* Navigation */
.main-nav {
    background-color: #333;
    margin-top: 15px;
    clear: both;
    border-radius: 12px;
}

.main-nav ul {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    width: 100%;
}

.main-nav li {
    position: relative;
    flex: 1;
}

.main-nav a {
    color: #fff;
    text-decoration: none;
    padding: 14px 20px;
    display: block;
    font-weight: 500;
    transition: background-color 0.2s ease;
    text-align: center;
    white-space: nowrap;
}

.main-nav a:hover,
.main-nav a.active {
    background-color: #d63031;
    border-radius: 6px;
}

/* Main Content */
main.container {
    padding: 30px 0;
}

/* Alert Messages */
.alert {
    padding: 14px 18px;
    margin-bottom: 20px;
    border-radius: 6px;
    font-weight: 500;
    border-left: 4px solid;
}

.alert-success {
    background-color: #d4edda;
    border-left-color: #28a745;
    color: #155724;
}

.alert-info {
    background-color: #d1ecf1;
    border-left-color: #17a2b8;
    color: #0c5460;
}

.alert-warning {
    background-color: #fff3cd;
    border-left-color: #ffc107;
    color: #856404;
}

.alert-danger {
    background-color: #f8d7da;
    border-left-color: #dc3545;
    color: #721c24;
}

/* Footer */
footer {
    background-color: #f8f8f8;
    border-top: 1px solid #e7e7e7;
    margin-top: 40px;
    padding: 20px 0;
}

footer p {
    text-align: center;
    color: #777;
    font-size: 12px;
    line-height: 1.4;
    margin: 0;
}

footer a {
    color: #777;
    text-decoration: none;
    transition: color 0.2s ease;
}

footer a:hover {
    color: #d63031;
    text-decoration: underline;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        width: 95%;
        padding: 0 15px;
    }
    
    .logo,
    #user-info {
        float: none;
        text-align: center;
        padding: 10px 0;
    }
    
    .main-nav {
        margin-top: 10px;
        border-radius: 0;
    }
    
    .main-nav ul {
        flex-direction: column;
    }
    
    .main-nav a {
        border-bottom: 1px solid #555;
        padding: 12px 20px;
    }
    
    .main-nav li:last-child a {
        border-bottom: none;
    }
    
    main.container {
        padding: 20px 0;
    }

    footer p {
        font-size: 11px;
        padding: 15px 10px;
    }
}