* {
    box-sizing: border-box;
}

body {
    min-height: 100vh;
    margin: 0;
    padding: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #f9f9f9;
    font-family: "Noto Sans KR", sans-serif;
}

.login-container {
    width: min(300px, 100%);
    padding: 40px;
    border-radius: 10px;
    background-color: #fff;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
    text-align: center;
}

.login-container h2 {
    margin: 0 0 20px;
    color: #222832;
    font-size: 24px;
    font-weight: 700;
    letter-spacing: 0;
}

.field-group {
    position: relative;
}

.floating-input {
    width: 100%;
    padding: 22px 12px 6px;
    border: 1px solid #ccc;
    background-color: #fff;
    font: inherit;
    font-size: 14px;
    line-height: 1.4;
    outline: none;
    transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

#user_id.floating-input {
    border-radius: 5px 5px 0 0;
}

#password.floating-input {
    border-top: 0;
    border-radius: 0 0 5px 5px;
}

.field-group label {
    position: absolute;
    top: 50%;
    left: 12px;
    color: #9ca3af;
    font-size: 14px;
    pointer-events: none;
    transform: translateY(-55%);
    transition: all 0.15s ease;
}

.floating-input:focus + label,
.floating-input:not(:placeholder-shown) + label {
    top: 4px;
    color: #222832;
    font-size: 11px;
    transform: none;
}

.floating-input:focus {
    position: relative;
    z-index: 1;
    border-color: #222832;
    box-shadow: 0 0 0 1px rgba(34, 40, 50, 0.28);
}

button {
    width: 100%;
    margin-top: 12px;
    padding: 10px;
    border: 0;
    border-radius: 5px;
    background-color: #222832;
    color: #fff;
    font: inherit;
    font-weight: 700;
    cursor: pointer;
    transition: background-color 0.2s ease;
}

button:hover {
    background-color: #343c49;
}

.error-message {
    margin: 12px 0 0;
    color: #c62828;
    font-size: 13px;
}