/* 共通スタイル（外部フレームワーク不使用） */

:root {
    /* モダンな配色: インディゴ×バイオレットを基調に、スレート系ニュートラル */
    --color-primary: #4f46e5;        /* indigo-600 */
    --color-primary-dark: #4338ca;   /* indigo-700 */
    --color-primary-light: #eef2ff;  /* indigo-50 */
    --color-accent: #7c3aed;         /* violet-600 */
    --color-bg: #f8fafc;             /* slate-50 */
    --color-surface: #ffffff;
    --color-text: #1e293b;           /* slate-800 */
    --color-muted: #64748b;          /* slate-500 */
    --color-border: #e2e8f0;         /* slate-200 */
    --color-error: #dc2626;          /* red-600 */
    --color-success: #059669;        /* emerald-600 */
    /* ヘッダー等のグラデーション */
    --gradient-primary: linear-gradient(135deg, #4f46e5 0%, #7c3aed 100%);
    --font-base: "Hiragino Sans", "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: var(--font-base);
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-text);
    background: var(--color-bg);
}

.container {
    max-width: 960px;
    margin: 0 auto;
    padding: 0 16px;
}

.site-header {
    background: var(--gradient-primary);
    color: #fff;
    padding: 16px 0;
}

.site-header-inner {
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.96);
    border-radius: 10px;
    padding: 10px 20px;
    box-shadow: 0 2px 8px rgba(15, 23, 42, 0.12);
}

/* BMSTブランドロゴ */
.brand-logo {
    display: block;
    width: auto;
    height: auto;
    max-width: 100%;
    object-fit: contain;
}

.brand-logo-header {
    max-height: 40px;
}

.brand-logo-hero {
    max-height: 72px;
    margin: 0 auto;
}

.brand-logo-nav {
    max-height: 32px;
}

.brand-logo-login {
    max-height: 56px;
    margin: 0 auto 8px;
}

.brand-logo-participant {
    max-height: 28px;
}

.brand-icon {
    display: block;
    width: 32px;
    height: 32px;
    object-fit: contain;
    flex-shrink: 0;
}

.brand-icon-participant {
    margin: 0 auto 6px;
}

.brand-icon-chat {
    width: 28px;
    height: 28px;
}

.home-logo-wrap,
.login-logo-wrap {
    text-align: center;
    margin-bottom: 12px;
}

.operator-brand-link {
    display: inline-flex;
    align-items: center;
    text-decoration: none;
    line-height: 0;
}

.participant-header-brand {
    margin-bottom: 8px;
    text-align: center;
}

.participant-header-brand .brand-logo-participant {
    margin: 0 auto;
    filter: brightness(0) invert(1);
}

.participant-header-brand .brand-icon-participant {
    margin: 0 auto 6px;
}

/* チャット内の送信画像（講師・生徒共通） */
.guidance-image-link {
    display: block;
    margin-top: 10px;
    text-decoration: none;
}

.guidance-chat-image {
    display: block;
    width: auto;
    max-width: 100%;
    max-height: 420px;
    border-radius: 12px;
    object-fit: contain;
    background: #fff;
    border: 1px solid var(--color-border);
}

.site-title {
    margin: 0;
    font-size: 1.25rem;
}

.site-title-sub {
    font-size: 0.85rem;
    font-weight: normal;
    opacity: 0.9;
}

.main-content {
    padding: 24px 16px;
    min-height: 60vh;
}

.site-footer {
    border-top: 1px solid var(--color-border);
    padding: 16px 0;
    text-align: center;
    font-size: 0.875rem;
    color: #666;
}

/* トップページ */
.home-hero {
    background: #fff;
    border-radius: 8px;
    padding: 32px 24px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
}

.home-hero h2 {
    margin-top: 0;
    margin-bottom: 8px;
    color: var(--color-primary);
    font-size: 2rem;
    letter-spacing: 0.08em;
}

.home-system-name {
    margin: 0 0 16px;
    font-size: 1.05rem;
    color: #444;
}

.lead {
    font-size: 1.05rem;
    color: #555;
}

.home-actions {
    margin: 24px 0;
}

.home-info {
    margin-top: 32px;
    padding-top: 24px;
    border-top: 1px solid var(--color-border);
}

.home-info h3 {
    font-size: 1.1rem;
}

.note code {
    background: #eef2f6;
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 0.9rem;
    word-break: break-all;
}

/* ボタン */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: 6px;
    text-decoration: none;
    font-weight: bold;
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background: var(--color-primary);
    color: #fff;
}

.btn-primary:hover {
    background: var(--color-primary-dark);
}

.btn-secondary {
    background: #fff;
    color: var(--color-primary);
    border: 2px solid var(--color-primary);
}

/* アラート */
.alert {
    padding: 12px 16px;
    border-radius: 6px;
    margin-bottom: 16px;
}

.alert-error {
    background: #fdecea;
    color: var(--color-error);
    border: 1px solid #f5c6cb;
}

.alert-success {
    background: #eafaf1;
    color: var(--color-success);
    border: 1px solid #b8e6cc;
}

/* プレースホルダ */
.placeholder-box {
    background: #fff;
    border-radius: 8px;
    padding: 32px 24px;
    text-align: center;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
}

.placeholder-phase {
    color: #888;
    font-size: 1.1rem;
}

/* 参加者画面向け（フェーズ3以降で拡張） */
@media (max-width: 600px) {
    .home-hero h2 {
        font-size: 1.25rem;
    }

    .btn {
        display: block;
        text-align: center;
    }
}