/* ============================================================
   多人联机棋类平台 · 公共样式（模式选择页 + 通用组件）
   全部图标为 SVG，本文件不含任何图片资源
   ============================================================ */
:root {
    --primary: #87CEEB;
    --primary-dark: #4682B4;
    --bg: #f0f4f8;
    --card: #FFFFFF;
    --text: #333;
    --gray: #666;
    --danger: #e05c5c;
    --success: #4caf50;
    --radius: 14px;
    --shadow: 0 8px 24px rgba(70, 130, 180, 0.18);
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
        "Helvetica Neue", "PingFang SC", "Microsoft YaHei", sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    position: relative;
}

body::before {
    content: '';
    position: fixed; inset: 0;
    background:
        radial-gradient(ellipse at 20% 50%, rgba(135,206,235,0.12), transparent 60%),
        radial-gradient(ellipse at 80% 20%, rgba(70,130,180,0.08), transparent 50%);
    z-index: 0;
    pointer-events: none;
}

.container { position: relative; z-index: 1; width: 100%; max-width: 1080px; margin: 0 auto; padding: 20px 16px; }

/* ---- 顶部栏 ---- */
.topbar {
    display: flex; align-items: center; justify-content: space-between;
    padding: 10px 4px 18px;
}
.topbar .brand { font-size: 1.25rem; font-weight: 700; color: var(--primary-dark); }
.topbar .brand small { font-weight: 400; color: var(--gray); margin-left: 8px; font-size: 0.8rem; }

/* ---- 标题 ---- */
.page-title { text-align: center; margin: 8px 0 22px; }
.page-title h1 { font-size: clamp(1.4rem, 4vw, 1.9rem); color: var(--primary-dark); }
.page-title p { color: var(--gray); margin-top: 6px; font-size: 0.95rem; }

/* ---- 卡片网格：棋种选择 ---- */
.game-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(210px, 1fr));
    gap: 16px;
}
.game-card {
    background: var(--card);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 22px 18px;
    cursor: pointer;
    border: 2px solid transparent;
    transition: transform 0.25s cubic-bezier(0.34,1.56,0.64,1), border-color 0.2s, box-shadow 0.2s;
    text-align: center;
    user-select: none;
}
.game-card:hover { transform: translateY(-3px); box-shadow: 0 12px 30px rgba(70,130,180,0.28); }
.game-card.selected { border-color: var(--primary-dark); box-shadow: 0 0 0 3px rgba(70,130,180,0.25); }
.game-card .g-icon { width: 64px; height: 64px; margin: 0 auto 12px; color: var(--primary-dark); }
.game-card h3 { font-size: 1.05rem; margin-bottom: 6px; }
.game-card p { font-size: 0.82rem; color: var(--gray); line-height: 1.5; }
.game-card .g-tag {
    display: inline-block; margin-top: 10px; padding: 3px 12px;
    border-radius: 999px; background: rgba(135,206,235,0.2); color: var(--primary-dark);
    font-size: 0.75rem; font-weight: 600;
}

/* ---- 操作面板（创建/加入） ---- */
.action-panel {
    margin-top: 26px;
    background: var(--card);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 22px;
}
.action-panel h2 { font-size: 1.05rem; color: var(--primary-dark); margin-bottom: 16px; }
.panel-cols { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }
@media (max-width: 720px) { .panel-cols { grid-template-columns: 1fr; } }

.panel-box { border: 1px dashed #c5d8e8; border-radius: 12px; padding: 18px; }
.panel-box h3 { font-size: 0.95rem; margin-bottom: 12px; display: flex; align-items: center; gap: 8px; }
.panel-box h3 svg { color: var(--primary-dark); }

/* ---- 表单 ---- */
.field { margin-bottom: 12px; }
.field label { display: block; font-size: 0.82rem; color: var(--gray); margin-bottom: 5px; }
.field input[type="text"], .field input[type="password"] {
    width: 100%; padding: 10px 12px;
    border: 1px solid #cbd8e5; border-radius: 8px;
    font-size: 1rem; outline: none; transition: border-color 0.2s, box-shadow 0.2s;
}
.field input:focus { border-color: var(--primary-dark); box-shadow: 0 0 0 3px rgba(70,130,180,0.15); }
.field input.room-input { text-transform: uppercase; letter-spacing: 0.35em; font-weight: 700; }

/* ---- 按钮 ---- */
.btn {
    display: inline-flex; align-items: center; justify-content: center; gap: 8px;
    padding: 11px 22px; border: none; border-radius: 10px;
    font-size: 0.95rem; font-weight: 600; cursor: pointer;
    transition: transform 0.15s, box-shadow 0.2s, opacity 0.2s;
    color: #fff; background: var(--primary-dark);
}
.btn:hover { transform: translateY(-1px); box-shadow: 0 6px 16px rgba(70,130,180,0.35); }
.btn:active { transform: translateY(0); }
.btn:disabled { opacity: 0.55; cursor: not-allowed; transform: none; box-shadow: none; }
.btn svg { color: #fff; }
.btn-block { width: 100%; }
.btn-primary { background: var(--primary-dark); }
.btn-ghost { background: transparent; color: var(--primary-dark); border: 1.5px solid var(--primary-dark); }
.btn-ghost svg { color: var(--primary-dark); }
.btn-danger { background: var(--danger); }
.btn-success { background: var(--success); }
.btn-sm { padding: 7px 14px; font-size: 0.82rem; }

/* ---- 提示条 ---- */
.msg { margin-top: 12px; padding: 10px 14px; border-radius: 8px; font-size: 0.88rem; display: none; }
.msg.show { display: block; }
.msg.error { background: rgba(224,92,92,0.12); color: #b04545; }
.msg.ok { background: rgba(76,175,80,0.12); color: #3c8a40; }

/* ---- 房间类型按钮（私有/公共） ---- */
.vis-btn.active { background: var(--primary-dark); color: #fff; border-color: var(--primary-dark); }
.vis-btn.active svg { color: #fff; }

/* ---- 公共房间列表 ---- */
.pub-item {
    display: flex; align-items: center; justify-content: space-between; gap: 12px;
    padding: 14px 16px; border: 1px solid #e3ecf5; border-radius: 12px;
    margin-bottom: 10px; background: #fbfdff; flex-wrap: wrap;
}
.pub-item:hover { border-color: var(--primary); box-shadow: 0 4px 14px rgba(135,206,235,0.25); }
.pub-info { flex: 1; min-width: 200px; }
.pub-title { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.pub-title b { font-size: 0.98rem; color: var(--primary-dark); }
.pub-room {
    font-family: monospace; letter-spacing: 0.12em; font-weight: 700;
    background: rgba(135,206,235,0.18); color: var(--primary-dark);
    padding: 2px 8px; border-radius: 6px; font-size: 0.85rem;
}
.pub-host { font-size: 0.82rem; color: var(--gray); }
.pub-meta {
    display: flex; gap: 14px; flex-wrap: wrap; margin-top: 6px;
    font-size: 0.78rem; color: var(--gray);
}
.pub-actions { display: flex; gap: 8px; align-items: center; }
.pub-badge {
    font-size: 0.75rem; color: var(--gray); background: #f0f4f8;
    padding: 3px 10px; border-radius: 999px; white-space: nowrap;
}

/* ---- AI 对战：10 档难度按钮 ---- */
.diff-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 8px; margin-bottom: 12px; }
@media (max-width: 560px) { .diff-grid { grid-template-columns: repeat(2, 1fr); } }
.diff-btn { padding: 8px 6px; font-size: 0.8rem; }
.diff-btn.active { background: var(--primary-dark); color: #fff; border-color: var(--primary-dark); }
.diff-btn.active svg { color: #fff; }

/* ---- 页脚 ---- */
.footer { text-align: center; color: var(--gray); font-size: 0.78rem; padding: 24px 0 12px; }