/* 基本設定 */
:root {
    --primary-color: #2563eb;
    --accent-color: #ef4444;
    --bg-color: #f8fafc;
    --text-color: #1e293b;
    --card-bg: #ffffff;
}

body {
    font-family: "Helvetica Neue", Arial, "Hiragino Kaku Gothic ProN", "Hiragino Sans", Meiryo, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    line-height: 1.6;
}

.container {
    max-width: 900px;
    margin: 40px auto;
    background: var(--card-bg);
    box-shadow: 0 10px 25px rgba(0,0,0,0.05);
    border-radius: 16px;
    overflow: hidden;
}

/* ヘッダー・ヒーローエリア */
.hero {
    position: relative;
    color: white;
}

.hero-img {
    width: 100%;
    height: auto;
    display: block;
    filter: brightness(0.8);
}

.hero-content {
    padding: 30px;
    background: linear-gradient(to right, #1e293b, rgba(30, 41, 59, 0.7));
}

.subtitle {
    font-weight: bold;
    color: #93c5fd;
    text-transform: uppercase;
    margin: 0;
    letter-spacing: 2px;
}

h1 {
    margin: 10px 0 0;
    font-size: 2rem;
    line-height: 1.2;
}

h1 span {
    font-size: 1.5rem;
    color: #cbd5e1;
    font-weight: normal;
}

/* メインコンテンツ */
.content {
    padding: 40px;
}

h2 {
    border-left: 5px solid var(--primary-color);
    padding-left: 15px;
    font-size: 1.25rem;
    margin-bottom: 20px;
}

.info-card {
    margin-bottom: 40px;
}

.schedule {
    list-style: none;
    padding: 0;
}

.schedule li {
    background: #f1f5f9;
    margin-bottom: 10px;
    padding: 15px;
    border-radius: 8px;
    display: flex;
    flex-wrap: wrap;
}

.date {
    font-weight: bold;
    color: var(--primary-color);
    margin-right: 20px;
    min-width: 220px;
}

.organizer {
    margin-top: 20px;
    font-size: 0.95rem;
    color: #64748b;
}

/* ボタン */
.button-group {
    display: flex;
    gap: 15px;
    flex-wrap: wrap;
}

.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: bold;
    transition: all 0.3s;
    text-align: center;
}

.btn.red {
    background-color: var(--accent-color);
    color: white;
}

.btn.red:hover {
    background-color: #dc2626;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(239, 68, 68, 0.3);
}

/* フッター */
footer {
    margin-top: 50px;
    text-align: center;
    border-top: 1px solid #e2e8f0;
    padding-top: 20px;
}

.back-link {
    text-decoration: none;
    color: #64748b;
    font-size: 0.9rem;
}

.back-link:hover {
    color: var(--primary-color);
}

/* スマホ対応 */
@media (max-width: 600px) {
    .container {
        margin: 0;
        border-radius: 0;
    }
    .hero-content {
        padding: 20px;
    }
    h1 { font-size: 1.5rem; }
    .content { padding: 20px; }
    .btn { width: 100%; }
}