/* ===================================
   ログイン画面 ダークモード
=================================== */
:root {
    /* 背景色 */
    --bg-primary: #0a0a0a;
    --bg-secondary: #121212;
    --bg-card: #1a1a1a;
    --bg-hover: #252525;
    
    /* テキスト色 */
    --text-primary: #e8e8e8;
    --text-secondary: #a8a8a8;
    --text-muted: #666666;
    
    /* アクセントカラー */
    --accent-primary: #00d4ff;
    --accent-secondary: #0099cc;
    --accent-glow: rgba(0, 212, 255, 0.4);
    
    /* ステータスカラー */
    --success: #00ff88;
    --warning: #ffaa00;
    --error: #ff4444;
    
    /* グラデーション */
    --gradient-primary: linear-gradient(135deg, #0a0a0a 0%, #1a1a1a 100%);
    --gradient-accent: linear-gradient(135deg, #00d4ff 0%, #0099cc 100%);
    --gradient-card: linear-gradient(145deg, #1e1e1e, #161616);
    
    /* シャドウ */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.4);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.5);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.6);
    --shadow-glow: 0 0 20px var(--accent-glow);
}

body {
    background: var(--gradient-primary);
    position: relative;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

/* 背景パーティクル効果 */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: 
        radial-gradient(circle at 20% 80%, rgba(0, 212, 255, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(0, 153, 204, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 40% 40%, rgba(0, 255, 136, 0.05) 0%, transparent 50%);
    pointer-events: none;
    z-index: 1;
}

header,
main {
    width: 100%;
    padding: 20px;
    max-width: 600px;
    box-sizing: border-box;
    margin: 0 auto;
    position: relative;
    z-index: 2;
}

#header_top {
    margin: 40px 0 30px;
    text-align: center;
}

#header_top h1 img {
    opacity: 0.9;
    max-width: 200px;
    height: auto;
}

/* ログインフォームセクション */
#login_form_section {
    background: rgba(26, 26, 26, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    padding: 40px;
    box-shadow: var(--shadow-lg);
    position: relative;
    overflow: hidden;
}

/* グロー効果 */
#login_form_section::before {
    content: '';
    position: absolute;
    top: -2px;
    left: -2px;
    right: -2px;
    bottom: -2px;
    background: var(--gradient-accent);
    border-radius: 20px;
    opacity: 0;
    z-index: -1;
    transition: opacity 0.3s ease;
}

#login_form_section:hover::before {
    opacity: 0.3;
}

#login_form_section h2 {
    font-size: 2.5em;
    text-align: center;
    background: var(--gradient-accent);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 30px;
    font-weight: 700;
    letter-spacing: 2px;
}

/* エラーメッセージ */
#error_message {
    background: rgba(255, 68, 68, 0.1);
    border: 1px solid var(--error);
    border-radius: 8px;
    padding: 15px;
    margin-bottom: 25px;
    text-align: center;
}

#error_message p {
    color: var(--error);
    font-size: 0.9rem;
    font-weight: 500;
}

/* フォーム要素 */
#login_form_section dl {
    display: flex;
    align-items: center;
    margin-top: 25px;
}

#login_form_section dt {
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    font-size: 14px;
    width: 150px;
    font-weight: 500;
}

#login_form_section dt span {
    margin-right: 8px;
    color: var(--accent-primary);
    font-size: 20px;
}

#login_form_section dd {
    width: calc(100% - 150px);
}

/* 入力フィールド */
#login_form_section dd input {
    width: 100%;
    height: 45px;
    background: var(--bg-secondary);
    border: 2px solid rgba(255, 255, 255, 0.1);
    border-radius: 8px;
    font-size: 1.1em;
    padding: 0 15px;
    color: var(--text-primary);
    transition: all 0.3s ease;
}

#login_form_section dd input:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(0, 212, 255, 0.1);
    background: var(--bg-card);
}

/* ユーザーID入力 */
#login_form_section dd #input_user_id {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 10px;
}

#login_form_section dd #input_user_id input {
    width: calc(33.333% - 10px);
    text-align: center;
    font-weight: 600;
    letter-spacing: 2px;
}

#login_form_section dd #input_user_id span {
    color: var(--text-secondary);
    font-size: 1.2em;
    font-weight: 500;
}

/* ログインボタン */
.send_btn {
    text-align: center;
    margin-top: 40px;
}

.send_btn input[type="submit"] {
    width: 100%;
    max-width: 300px;
    height: 50px;
    background: var(--gradient-accent);
    border: none;
    border-radius: 25px;
    color: var(--bg-primary);
    font-size: 1.1em;
    font-weight: 700;
    letter-spacing: 1px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(0, 212, 255, 0.3);
    text-transform: uppercase;
    position: relative;
    overflow: hidden;
}

.send_btn input[type="submit"]:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 25px rgba(0, 212, 255, 0.5);
}

.send_btn input[type="submit"]:active {
    transform: translateY(0);
}

/* ボタンのリップルエフェクト */
.send_btn input[type="submit"]::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.3);
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.send_btn input[type="submit"]:hover::before {
    width: 300px;
    height: 300px;
}

/* フッター */
footer {
    text-align: center;
    padding: 20px;
    color: var(--text-muted);
    font-size: 0.8rem;
    position: relative;
    z-index: 2;
}

footer p {
    margin: 5px 0;
}

footer a {
    color: var(--accent-primary);
    text-decoration: none;
    transition: color 0.3s ease;
}

footer a:hover {
    color: var(--accent-secondary);
    text-decoration: underline;
}

/* レスポンシブ */
@media (max-width: 768px) {
    #login_form_section {
        padding: 30px 20px;
    }
    
    #login_form_section dl {
        flex-direction: column;
        align-items: flex-start;
    }
    
    #login_form_section dt {
        width: 100%;
        margin-bottom: 10px;
    }
    
    #login_form_section dd {
        width: 100%;
    }
    
    #login_form_section dd #input_user_id input {
        font-size: 1em;
    }
}

/* アニメーション */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

#login_form_section {
    animation: fadeIn 0.6s ease-out;
}

/* ローディング状態 */
.loading {
    position: relative;
    overflow: hidden;
}

.loading::after {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(0, 212, 255, 0.2), transparent);
    animation: loading 1.5s infinite;
}

@keyframes loading {
    0% { left: -100%; }
    100% { left: 100%; }
}