body {
            background: #121212;
            color: white;
            font-family: sans-serif;
            display: flex;
            justify-content: center;
            align-items: center;
            min-height: 75vh;
            margin: 0;
            padding: 20px;
        }

        .login-card {
            background: #2F2F2F;
            padding: 40px;
            border-radius: 8px;
            width: 320px;
            text-align: center;
            max-width: 400px;
            position: relative;
        }

        .lang-switcher {
            position: absolute;
            top: 10px;
            right: 10px;
            display: flex;
            gap: 5px;
            background: #222;
            padding: 2px;
            border-radius: 4px;
        }

        .lang-btn {
            background: none; border: none; color: #666; font-size: 10px;
            padding: 2px 6px; border-radius: 3px; cursor: pointer; font-weight: 700;
            margin: 0;
        }

        .lang-btn.active {
            background: #333;
            color: #00f2ea;
        }

        h2 {
            margin-top: 0;
            margin-bottom: 10px;
        }

        .subtitle {
            font-size: 13px;
            color: #ccc;
            margin-bottom: 25px;
            line-height: 1.5;
        }

        input {
            width: 100%;
            padding: 12px;
            margin: 10px 0;
            border: 1px solid #444;
            background: #121212;
            color: white;
            border-radius: 4px;
            box-sizing: border-box;
        }

        button[type="submit"] {
            width: 100%;
            padding: 12px;
            background: #fe2c55;
            border: none;
            color: white;
            font-weight: bold;
            border-radius: 4px;
            cursor: pointer;
            margin-top: 15px;
        }

        button[type="submit"]:hover {
            background: #ef2950;
        }

        button:disabled {
            background: #555;
            color: #aaa;
            cursor: not-allowed;
        }

        /* メッセージ */
        .msg-box {
            font-size: 13px;
            margin-bottom: 20px;
            padding: 8px;
            border-radius: 4px;
            display: none;
        }
        .msg-error {
            color: #fe2c55;
            border: 1px solid #fe2c55;
            background: rgba(254,44,85,0.1);
        }
        .msg-success {
            color: #00f2ea;
            border: 1px solid #00f2ea;
            background: rgba(0,242,234,0.1);
        }

        .back-link {
            display: inline-block;
            margin-top: 20px;
            font-size: 13px;
            color: #00f2ea;
            text-decoration: none;
        }
        .back-link:hover {
            text-decoration: underline;
        }