/* ============================================================
   五子棋 AI — 样式表
   设计理念：素雅、温润，如棋盘与棋子般沉静
   ============================================================ */

/* --- CSS 变量 --- */
:root {
    --bg:            #f7f3eb;
    --surface:       #fefcf7;
    --border:        #d4c5a9;
    --text:          #3d3226;
    --text-muted:    #8a7b68;
    --accent:        #a0522d;
    --accent-light:  #c67d56;
    --black-stone:   #2c2c2c;
    --white-stone:   #f5f0e5;
    --shadow:        0 2px 16px rgba(60, 40, 20, 0.10);
    --shadow-lg:     0 8px 40px rgba(60, 40, 20, 0.18);
    --radius:        10px;
    --transition:    0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

/* --- 基础重置 --- */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background-image:
        radial-gradient(ellipse at 20% 50%, rgba(180, 160, 130, 0.12) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 20%, rgba(180, 160, 130, 0.08) 0%, transparent 50%);
}

/* --- 容器 --- */
.container {
    max-width: 820px;
    width: 100%;
    padding: 24px;
}

/* --- 标题 --- */
.header {
    text-align: center;
    margin-bottom: 20px;
}

.title {
    font-size: 2rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    color: var(--text);
    margin-bottom: 2px;
}

.subtitle {
    font-size: 0.82rem;
    color: var(--text-muted);
    letter-spacing: 0.04em;
}

/* --- 游戏主区域 --- */
.game-area {
    display: flex;
    gap: 28px;
    align-items: flex-start;
    justify-content: center;
    flex-wrap: wrap;
}

/* --- 棋盘容器 --- */
.board-wrapper {
    background: var(--surface);
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    padding: 18px;
    position: relative;
}

/* 模拟木纹 */
.board-wrapper::before {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: var(--radius);
    background:
        repeating-linear-gradient(
            2deg,
            transparent,
            transparent 3px,
            rgba(139, 115, 85, 0.03) 3px,
            rgba(139, 115, 85, 0.03) 4px
        ),
        linear-gradient(175deg, #e8d5b0 0%, #dcc8a0 40%, #e0cdab 100%);
    z-index: 0;
    border: 2px solid #c4a882;
}

.board-wrapper > canvas {
    position: relative;
    z-index: 1;
    display: block;
    border-radius: 4px;
}

/* --- 信息面板 --- */
.info-panel {
    flex: 0 0 200px;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

/* 状态卡片 */
.status-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 14px 16px;
    display: flex;
    align-items: center;
    gap: 10px;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.status-card.ai-thinking {
    border-color: var(--accent-light);
}

.status-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    flex-shrink: 0;
    background: #555;
    transition: background var(--transition);
}

.status-dot.black-turn { background: #3a3a3a; }
.status-dot.white-turn { background: #d5cec0; border: 1px solid #bbb; }
.status-dot.game-over  { background: var(--accent); }

#statusText {
    font-size: 0.9rem;
    color: var(--text);
    font-weight: 500;
}

/* 统计 */
.stats {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 12px 16px;
    display: flex;
    justify-content: space-around;
    box-shadow: var(--shadow);
}

.stat-item {
    text-align: center;
}

.stat-label {
    display: block;
    font-size: 0.7rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 2px;
}

.stat-value {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text);
}

.piece-label {
    font-size: 1.3rem;
}

.black-label { color: #3a3a3a; }
.white-label { color: #c5b99a; }

/* 按钮 */
.actions {
    display: flex;
    gap: 10px;
}

.btn {
    flex: 1;
    padding: 10px 0;
    border: none;
    border-radius: 6px;
    font-size: 0.88rem;
    font-weight: 600;
    cursor: pointer;
    letter-spacing: 0.04em;
    transition: var(--transition);
}

.btn-primary {
    background: var(--accent);
    color: #fff;
}
.btn-primary:hover {
    background: var(--accent-light);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(160, 82, 45, 0.30);
}

.btn-secondary {
    background: var(--surface);
    color: var(--text);
    border: 1px solid var(--border);
}
.btn-secondary:hover {
    background: #f0ebe0;
    border-color: #b8a088;
}

.btn:active {
    transform: scale(0.97);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

/* 算法说明 */
.legend {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 14px 16px;
    box-shadow: var(--shadow);
}

.legend-title {
    font-size: 0.78rem;
    font-weight: 600;
    color: var(--text-muted);
    margin-bottom: 8px;
    letter-spacing: 0.05em;
}

.legend-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.legend-list li {
    font-size: 0.75rem;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    gap: 6px;
}

.legend-num {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 18px;
    height: 18px;
    font-size: 0.65rem;
    font-weight: 700;
    color: var(--accent);
    background: rgba(160, 82, 45, 0.08);
    border-radius: 50%;
    flex-shrink: 0;
}

/* --- 胜利弹窗 --- */
.overlay {
    position: fixed;
    inset: 0;
    background: rgba(30, 20, 10, 0.45);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    animation: fadeIn 0.3s ease;
    backdrop-filter: blur(3px);
    -webkit-backdrop-filter: blur(3px);
}

.hidden { display: none; }

.win-dialog {
    background: var(--surface);
    border-radius: 16px;
    padding: 36px 48px;
    text-align: center;
    box-shadow: 0 20px 60px rgba(0,0,0,0.25);
    animation: scaleIn 0.35s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    max-width: 320px;
}

.win-icon {
    font-size: 3rem;
    margin-bottom: 8px;
}

.win-text {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 4px;
}

.win-sub {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-bottom: 20px;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to   { opacity: 1; }
}

@keyframes scaleIn {
    from { transform: scale(0.85); opacity: 0; }
    to   { transform: scale(1);    opacity: 1; }
}

/* --- 响应式 --- */
@media (max-width: 660px) {
    .game-area {
        flex-direction: column;
        align-items: center;
    }
    .info-panel {
        flex: 0 0 auto;
        width: 100%;
        max-width: 400px;
    }
    .title { font-size: 1.5rem; }
}