:root {
    --bg-color: #fafafa;
    --text-color: #333333;
    --island-bg: #e0e0e0;
    --btn-default-bg: #e9eef6;
    --btn-default-icon: #ffffff;
    --btn-active-bg: #d3e3fd;
    --btn-active-icon: #1b51a3;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body {
    font-family: sans-serif; background-color: var(--bg-color);
    padding-bottom: 120px; padding-top: 60px;
}
.top-nav {
    position: fixed; top: 0; width: 100%; background: rgba(255,255,255,0.9);
    backdrop-filter: blur(10px); z-index: 10; border-bottom: 1px solid #eee;
    overflow-x: auto; white-space: nowrap;
}
.top-tabs { display: flex; padding: 0 10px; }
.top-tab {
    padding: 15px; border: none; background: none; font-size: 14px;
    font-weight: bold; color: #888; position: relative;
}
.top-tab.active { color: var(--text-color); }
.top-tab.active::after {
    content: ''; position: absolute; bottom: 0; left: 20%; width: 60%;
    height: 4px; background-color: var(--btn-active-icon); border-radius: 2px;
}
#main-content { padding: 15px; }
.card {
    background: #fff; border-radius: 15px; padding: 15px; margin-bottom: 15px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}
.card-source { font-size: 11px; color: var(--btn-active-icon); font-weight: bold; }
.card-title { font-size: 16px; font-weight: bold; margin: 5px 0; }
.card-desc { font-size: 14px; color: #666; display: none; margin: 10px 0; line-height: 1.6; }
.card.expanded .card-desc { display: block; }
.btn-expand, .btn-link {
    padding: 8px 15px; border-radius: 20px; font-size: 12px; border: none; font-weight: bold; cursor: pointer;
}
.btn-expand { background: #f0f0f0; }
.btn-link { background: var(--btn-active-icon); color: #fff; text-decoration: none; display: none; margin-left: 5px; }
.card.expanded .btn-link { display: inline-block; }
.bottom-nav { position: fixed; bottom: 30px; left: 0; width: 100%; display: flex; justify-content: center; z-index: 100; }
.nav-island {
    background-color: var(--island-bg); border-radius: 50px;
    display: flex; gap: 10px; padding: 10px; box-shadow: 0 5px 20px rgba(0,0,0,0.1);
}
.nav-btn {
    width: 55px; height: 55px; border-radius: 50%; border: none;
    background-color: var(--btn-default-bg); color: var(--btn-default-icon);
    display: flex; justify-content: center; align-items: center; transition: 0.2s; cursor: pointer;
}
.nav-btn.active { background-color: var(--btn-active-bg); color: var(--btn-active-icon); }
input[type="text"] { width: 100%; padding: 15px; border: 1px solid #ddd; border-radius: 10px; font-size: 16px; margin-bottom: 10px; }

/* 通知ボタン用 */
.notification-banner {
    background: #fff; padding: 15px; border-radius: 12px; border: 2px solid var(--btn-active-bg); margin-bottom: 20px;
}