/* --- 基本リセットはそのまま --- */
body {
    background:
      radial-gradient(circle at 20% 25%, rgba(39, 199, 255, 0.25) 15%, transparent 40%),
      radial-gradient(circle at 80% 75%, rgba(39, 199, 255, 0.15) 10%, transparent 30%),
      radial-gradient(circle at 50% 50%, rgba(39, 199, 255, 0.1) 8%, transparent 25%),
      rgba(240, 249, 255, 0.95);
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    font-family: "Noto Sans JP", "Rounded Mplus 1c", Arial, sans-serif;
    margin: 0;
    color: #10375c; /* ネイビー系の濃いめカラー */
    overflow: hidden;
    position: relative;
}

/* ページ読み込み時に上昇フェードイン */
@keyframes fadeInUp {
    0% {opacity: 0; transform: translateY(25px);}
    100% {opacity: 1; transform: translateY(0);}
}

.background-overlay {
    position: absolute;
    top: 0; left: 0; width: 100%; height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    animation: fadeInUp 0.7s ease-out forwards;
}

/* ポップアップ */
.login-popup {
    background: rgba(39, 199, 255, 0.3);
    backdrop-filter: blur(12px);
    padding: 32px 28px;
    border-radius: 20px;
    box-shadow: 0 12px 24px rgba(16, 55, 92, 0.25);
    width: 90%;
    max-width: 420px;
    text-align: center;
    border: 2px solid rgba(39, 199, 255, 0.35);
}

/* タイトル */
.login-popup h2 {
    font-size: 26px;
    margin-bottom: 24px;
    color: #1768a1;
    font-weight: 700;
    letter-spacing: 0.05em;
}

/* エラーメッセージ */
.error-message {
    color: #d64541;
    background: #ffe6e6;
    border-radius: 10px;
    padding: 10px 14px;
    font-weight: 600;
    margin-bottom: 18px;
    box-shadow: 0 0 8px rgba(214, 69, 65, 0.4);
}

/* 入力コンテナ */
.input-container {
    margin-bottom: 18px;
    text-align: left;
}

.input-container label {
    font-size: 14px;
    margin-bottom: 6px;
    display: block;
    color: #3a5068;
    font-weight: 600;
}

/* 入力欄 */
.input-container input {
    width: 100%;
    padding: 12px 14px;
    font-size: 17px;
    border: 1.8px solid #9fc8e8;
    border-radius: 12px;
    background: rgba(255 255 255 / 0.9);
    color: #10375c;
    box-sizing: border-box;
    transition: border-color 0.3s ease, box-shadow 0.3s ease;
    font-weight: 500;
}

/* フォーカス時 */
.input-container input:focus {
    outline: none;
    border-color: #27c7ff;
    box-shadow: 0 0 12px 3px rgba(39, 199, 255, 0.4);
    background-color: #f0fbff;
}

/* ログインボタン */
.login-btn {
    background-color: #27c7ff;
    color: white;
    border: none;
    padding: 16px 36px;
    font-size: 20px;
    border-radius: 14px;
    cursor: pointer;
    width: 100%;
    margin-top: 12px;
    font-weight: 700;
    box-shadow: 0 8px 18px rgba(39, 199, 255, 0.5);
    transition: background-color 0.3s ease, transform 0.2s ease;
    user-select: none;
    position: relative;
}

/* 押下時のアニメーション */
@keyframes btnBounce {
    0%   { transform: scale(1); }
    50%  { transform: scale(0.92); }
    100% { transform: scale(1); }
}
.login-btn:active {
    animation: btnBounce 0.3s ease;
}

/* ホバー時 */
.login-btn:hover {
    background-color: #1d99c8;
    box-shadow: 0 10px 22px rgba(29, 153, 200, 0.7);
    transform: translateY(-2px);
}

/* レスポンシブ対応 */
@media screen and (max-width: 768px) {
    .login-popup {
        padding: 24px 20px;
        max-width: 95%;
    }
    .login-popup h2 {
        font-size: 22px;
    }
    .input-container input {
        font-size: 15px;
    }
    .login-btn {
        font-size: 18px;
        padding: 14px 28px;
    }
}

@media screen and (max-width: 480px) {
    .login-popup {
        padding: 18px 16px;
    }
    .login-popup h2 {
        font-size: 20px;
    }
    .input-container input {
        font-size: 14px;
    }
    .login-btn {
        font-size: 16px;
        padding: 12px 22px;
    }
}