:root {
    --bg: #f6f5f2;
    --card-bg: #ffffff;
    --text: #262421;
    --muted: #7a756c;
    --accent: #2b6cb0;
    --accent-hover: #1e4e82;
    --danger: #b5432c;
    --border: #e3ddd2;
    font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Yu Gothic", sans-serif;
}

* { box-sizing: border-box; }

body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
}

/* ログイン画面 */
.page-login {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
}

.login-card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 2.5rem;
    width: 100%;
    max-width: 360px;
}

.login-card h1 {
    margin: 0 0 1.5rem;
    font-size: 1.4rem;
}

.login-card form {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.login-card label {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
    font-size: 0.9rem;
    color: var(--muted);
}

.login-card input {
    padding: 0.6rem 0.75rem;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 1rem;
}

.login-card button {
    margin-top: 0.5rem;
    padding: 0.7rem;
    border: none;
    border-radius: 8px;
    background: var(--accent);
    color: #fff;
    font-size: 1rem;
    cursor: pointer;
}

.login-card button:hover { background: var(--accent-hover); }

.error { color: var(--danger); font-size: 0.9rem; }

/* ハブ画面 */
.hub-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1.25rem 1.5rem;
    border-bottom: 1px solid var(--border);
}

.hub-header h1 { margin: 0; font-size: 1.2rem; }

.logout-link { color: var(--muted); font-size: 0.85rem; text-decoration: none; }
.logout-link:hover { text-decoration: underline; }

.app-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 1rem;
    padding: 1.5rem;
    max-width: 960px;
    margin: 0 auto;
}

.app-card {
    display: block;
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.25rem;
    text-decoration: none;
    color: var(--text);
}

.app-card:hover { border-color: var(--accent); }
.app-card h2 { margin: 0 0 0.4rem; font-size: 1.05rem; }
.app-card p { margin: 0; font-size: 0.85rem; color: var(--muted); }

/* サブページ共通ヘッダー（アカデミックワードのゲーム画面・単語追加画面など） */
.game-header {
    padding: 1.25rem 1.5rem 0.75rem;
    text-align: center;
}

.game-header h1 { margin: 0 0 0.4rem; font-size: 1.15rem; }

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    font-size: 0.8rem;
    color: var(--muted);
    text-decoration: none;
    padding: 0.3rem 0.7rem;
    border: 1px solid var(--border);
    border-radius: 999px;
    margin-bottom: 0.6rem;
}
.back-link:hover { border-color: var(--accent); color: var(--accent); }