body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background-color: #f5f7fa;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}
.login-container {
    background-color: #fff;
    padding: 40px;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    width: 100%;
    max-width: 400px;
    text-align: center;
}
h2 {
    color: #1a202c;
    margin-bottom: 30px;
}
.input-group {
    text-align: left;
    margin-bottom: 20px;
}
label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: #4a5568;
}
input[type="text"], input[type="password"] {
    width: 100%;
    padding: 12px 15px;
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    font-size: 16px;
    box-sizing: border-box;
}
.btn {
    width: 100%;
    padding: 12px;
    background-color: #2f855a;
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s;
}
.btn:hover {
    background-color: #276749;
}
#mesaj-alani {
    margin-top: 20px;
    font-weight: 500;
}
.mesaj-hata {
    color: #e53e3e;
}
.mesaj-basari {
    color: #2f855a;
}