html, body {
    width: 100%;
    min-width: 0;
    max-width: 100vw;
    overflow-x: hidden;
    background: #f7f8fa;
    font-family: 'Segoe UI', 'Hiragino Sans', 'Meiryo', sans-serif;
    color: #222;
    margin: 0;
    padding: 0;
}

.container {
    width: 400px !important;
    max-width: 400px !important;
    margin: 40px auto;
    background: #fff;
    border-radius: 16px;
    box-shadow: 0 4px 24px rgba(0,0,0,0.08);
    padding: 32px 24px 24px 24px;
    box-sizing: border-box;
}
.container form {
    width: 100%;
}

.wide-container {
    width: 1000px;
    max-width: 1000px;
    margin: 40px auto;
    background: #fff;
    border-radius: 16px;
    box-shadow: 0 4px 24px rgba(0,0,0,0.08);
    padding: 32px 24px 24px 24px;
    box-sizing: border-box;
}

h1 {
    font-size: 1.6em;
    margin-bottom: 1.2em;
    color: #2a5d9f;
    letter-spacing: 0.05em;
    text-align: center;
}

label {
    display: block;
    margin-top: 1.2em;
    margin-bottom: 0.3em;
    font-weight: 500;
    width: 100%;
    max-width: 100%;
    box-sizing: border-box;
}

input[type="text"], input[type="password"], textarea {
    width: 100%;
    max-width: 100%;
    padding: 0.7em;
    border: 1px solid #cfd8dc;
    border-radius: 6px;
    font-size: 1em;
    margin-bottom: 0.5em;
    background: #f9fbfc;
    transition: border 0.2s;
    box-sizing: border-box;
}

input[type="text"]:focus, input[type="password"]:focus, textarea:focus {
    border: 1.5px solid #2a5d9f;
    outline: none;
    background: #fff;
}

button {
    width: 100%;
    max-width: 100%;
    padding: 0.9em;
    background: linear-gradient(90deg, #2a5d9f 60%, #4fc3f7 100%);
    color: #fff;
    border: none;
    border-radius: 6px;
    font-size: 1.1em;
    font-weight: bold;
    margin-top: 1.2em;
    cursor: pointer;
    transition: background 0.2s;
    box-sizing: border-box;
}

button:hover {
    background: linear-gradient(90deg, #1e3c72 60%, #29b6f6 100%);
}

.error {
    background: #ffeaea;
    color: #d32f2f;
    border: 1px solid #f8bbd0;
    border-radius: 6px;
    padding: 0.7em;
    margin-bottom: 1em;
    text-align: center;
}

.success {
    background: #e3fcec;
    color: #388e3c;
    border: 1px solid #b2dfdb;
    border-radius: 6px;
    padding: 0.7em;
    margin-bottom: 1em;
    text-align: center;
}

.admin-link {
    margin-top: 2em;
    text-align: center;
}

.admin-link a {
    color: #2a5d9f;
    text-decoration: none;
    font-weight: bold;
    transition: color 0.2s;
}

.admin-link a:hover {
    color: #1565c0;
    text-decoration: underline;
}

.problem-box, .score-box, .feedback-box {
    background: #f1f8ff;
    border-radius: 8px;
    padding: 1em;
    margin-bottom: 1.2em;
    border-left: 4px solid #2a5d9f;
}

.score {
    font-size: 1.5em;
    color: #2a5d9f;
    font-weight: bold;
}

@media (max-width: 600px) {
    .container {
        padding: 16px 4vw 16px 4vw;
    }
    h1 {
        font-size: 1.2em;
    }
}