/* ===== CSS变量系统 - 四主题支持 ===== */
:root {
    /* Modern Theme (默认) */
    --primary-color: #007AFF;
    --secondary-color: #5856D6;
    --success-color: #34C759;
    --warning-color: #FF9500;
    --error-color: #FF3B30;
    --background-color: #F2F2F7;
    --surface-color: rgba(255, 255, 255, 0.8);
    --text-primary: #1C1C1E;
    --text-secondary: #8E8E93;
    --border-color: rgba(60, 60, 67, 0.12);
    --shadow-color: rgba(0, 0, 0, 0.1);
    --tile-bg: #FFFFFF;
    --tile-border: #E5E5EA;
    --tile-text: #1C1C1E;
    --empty-space: rgba(0, 122, 255, 0.1);
    --tile-hover: rgba(0, 122, 255, 0.05);
    --tile-active: rgba(0, 122, 255, 0.2);
}

/* Classic Theme */
[data-theme="classic"] {
    --primary-color: #0078D4;
    --secondary-color: #6B69D6;
    --success-color: #107C10;
    --warning-color: #FF8C00;
    --error-color: #D13438;
    --background-color: #C0C0C0;
    --surface-color: #F0F0F0;
    --text-primary: #000000;
    --text-secondary: #666666;
    --border-color: #808080;
    --shadow-color: rgba(0, 0, 0, 0.3);
    --tile-bg: #FFFFFF;
    --tile-border: #808080;
    --tile-text: #000000;
    --empty-space: #E0E0E0;
    --tile-hover: #D4E7FF;
    --tile-active: #316AC5;
}

/* Dark Theme */
[data-theme="dark"] {
    --primary-color: #0A84FF;
    --secondary-color: #5E5CE6;
    --success-color: #30D158;
    --warning-color: #FF9F0A;
    --error-color: #FF453A;
    --background-color: #000000;
    --surface-color: rgba(28, 28, 30, 0.9);
    --text-primary: #FFFFFF;
    --text-secondary: #8E8E93;
    --border-color: rgba(84, 84, 88, 0.6);
    --shadow-color: rgba(0, 0, 0, 0.5);
    --tile-bg: #1C1C1E;
    --tile-border: #48484A;
    --tile-text: #FFFFFF;
    --empty-space: rgba(10, 132, 255, 0.2);
    --tile-hover: rgba(10, 132, 255, 0.1);
    --tile-active: rgba(10, 132, 255, 0.3);
}

/* Rainbow Theme */
[data-theme="rainbow"] {
    --primary-color: #FF6B6B;
    --secondary-color: #4ECDC4;
    --success-color: #45B7D1;
    --warning-color: #FFA07A;
    --error-color: #FF6B6B;
    --background-color: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --surface-color: rgba(255, 255, 255, 0.9);
    --text-primary: #2C3E50;
    --text-secondary: #7F8C8D;
    --border-color: rgba(52, 152, 219, 0.3);
    --shadow-color: rgba(0, 0, 0, 0.2);
    --tile-bg: #FFFFFF;
    --tile-border: #BDC3C7;
    --tile-text: #2C3E50;
    --empty-space: rgba(255, 107, 107, 0.2);
    --tile-hover: rgba(78, 205, 196, 0.1);
    --tile-active: rgba(255, 107, 107, 0.3);
}

/* ===== 基础样式重置 ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: var(--background-color);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ===== 游戏容器 ===== */
.game-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
    gap: 20px;
}

/* ===== 头部样式 ===== */
.game-header {
    background: var(--surface-color);
    backdrop-filter: blur(20px);
    border-radius: 16px;
    padding: 20px;
    box-shadow: 0 4px 20px var(--shadow-color);
    border: 1px solid var(--border-color);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 15px;
}

.game-title {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 10px;
}

.title-icon {
    font-size: 1.8rem;
}

.header-controls {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

/* ===== 按钮样式 ===== */
.btn {
    padding: 10px 16px;
    border: none;
    border-radius: 12px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    align-items: center;
    gap: 6px;
    text-decoration: none;
    user-select: none;
    -webkit-tap-highlight-color: transparent;
    transform: translateZ(0);
}

.btn-primary {
    background: var(--primary-color);
    color: white;
    box-shadow: 0 2px 8px rgba(0, 122, 255, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px) translateZ(0);
    box-shadow: 0 4px 16px rgba(0, 122, 255, 0.4);
}

.btn-secondary {
    background: var(--surface-color);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    box-shadow: 0 2px 8px var(--shadow-color);
}

.btn-secondary:hover {
    transform: translateY(-1px) translateZ(0);
    box-shadow: 0 4px 12px var(--shadow-color);
}

.btn:active {
    transform: translateY(0) translateZ(0);
}

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

.btn-icon {
    font-size: 16px;
}

/* ===== 游戏信息面板 ===== */
.game-info {
    background: var(--surface-color);
    backdrop-filter: blur(20px);
    border-radius: 16px;
    padding: 20px;
    box-shadow: 0 4px 20px var(--shadow-color);
    border: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

.info-section {
    display: flex;
    align-items: center;
    gap: 30px;
    flex-wrap: wrap;
}

.difficulty-selector,
.mode-selector {
    display: flex;
    align-items: center;
    gap: 10px;
}

.difficulty-selector label,
.mode-selector label {
    font-weight: 600;
    color: var(--text-primary);
}

.difficulty-select,
.mode-select {
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background: var(--tile-bg);
    color: var(--text-primary);
    font-size: 14px;
    cursor: pointer;
}

.game-stats {
    display: flex;
    gap: 20px;
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
}

.stat-label {
    font-size: 12px;
    color: var(--text-secondary);
    font-weight: 500;
}

.stat-value {
    font-size: 18px;
    font-weight: 700;
    color: var(--text-primary);
}

.game-controls {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

/* ===== 主游戏区域 ===== */
.game-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.puzzle-container {
    background: var(--surface-color);
    backdrop-filter: blur(20px);
    border-radius: 16px;
    padding: 20px;
    box-shadow: 0 4px 20px var(--shadow-color);
    border: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
}

/* ===== 拼图网格 ===== */
.puzzle-grid {
    display: grid;
    gap: 4px;
    background: var(--border-color);
    border-radius: 12px;
    padding: 4px;
    width: 100%;
    max-width: 400px;
    aspect-ratio: 1;
    position: relative;
}

.puzzle-grid.size-3x3 {
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(3, 1fr);
}

.puzzle-grid.size-4x4 {
    grid-template-columns: repeat(4, 1fr);
    grid-template-rows: repeat(4, 1fr);
}

.puzzle-grid.size-5x5 {
    grid-template-columns: repeat(5, 1fr);
    grid-template-rows: repeat(5, 1fr);
}

/* ===== 拼图块 ===== */
.puzzle-tile {
    background: var(--tile-bg);
    border: 1px solid var(--tile-border);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--tile-text);
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    user-select: none;
    -webkit-tap-highlight-color: transparent;
    position: relative;
    overflow: hidden;
    transform: translateZ(0);
}

.puzzle-tile:hover {
    background: var(--tile-hover);
    transform: translateY(-2px) translateZ(0);
    box-shadow: 0 4px 12px var(--shadow-color);
}

.puzzle-tile:active {
    background: var(--tile-active);
    transform: translateY(0) translateZ(0);
}

.puzzle-tile.moveable {
    cursor: pointer;
    box-shadow: 0 2px 8px var(--shadow-color);
}

.puzzle-tile.moveable:hover {
    box-shadow: 0 4px 16px var(--shadow-color);
}

.puzzle-tile.empty {
    background: var(--empty-space);
    border: 2px dashed var(--border-color);
    cursor: default;
}

.puzzle-tile.empty:hover {
    background: var(--empty-space);
    transform: none;
    box-shadow: none;
}

.puzzle-tile.hint {
    animation: hint-pulse 1s ease-in-out;
    box-shadow: 0 0 20px var(--primary-color);
}

.puzzle-tile.moving {
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 10;
}

/* 图片模式的拼图块 */
.puzzle-tile.image-tile {
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    font-size: 0;
}

.puzzle-tile.image-tile::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.1);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.puzzle-tile.image-tile:hover::before {
    opacity: 1;
}

/* ===== 图片上传区域 ===== */
.image-upload {
    width: 100%;
    max-width: 400px;
    text-align: center;
}

.upload-area {
    border: 2px dashed var(--border-color);
    border-radius: 12px;
    padding: 40px 20px;
    background: var(--tile-bg);
    transition: all 0.3s ease;
}

.upload-area:hover {
    border-color: var(--primary-color);
    background: var(--tile-hover);
}

.upload-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
    margin: 0 auto 10px;
}

.upload-btn:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
}

.upload-text {
    color: var(--text-secondary);
    font-size: 14px;
    margin: 0;
}

/* ===== 预设图片画廊 ===== */
.preset-images {
    width: 100%;
    max-width: 500px;
}

.preset-images h3 {
    margin-bottom: 15px;
    color: var(--text-primary);
    text-align: center;
}

.image-gallery {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 15px;
}

.image-option {
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    border-radius: 8px;
    overflow: hidden;
    background: var(--tile-bg);
    border: 2px solid transparent;
}

.image-option:hover {
    transform: translateY(-3px);
    box-shadow: 0 4px 12px var(--shadow-color);
    border-color: var(--primary-color);
}

.image-option img,
.image-option .image-placeholder {
    width: 100%;
    height: 80px;
    object-fit: cover;
    border-radius: 6px 6px 0 0;
    display: block;
}

.image-option span {
    display: block;
    padding: 8px;
    font-size: 12px;
    font-weight: 600;
    color: var(--text-primary);
}

/* ===== 游戏状态 ===== */
.game-status {
    background: var(--surface-color);
    backdrop-filter: blur(20px);
    border-radius: 16px;
    padding: 20px;
    box-shadow: 0 4px 20px var(--shadow-color);
    border: 1px solid var(--border-color);
    text-align: center;
}

.status-message {
    font-size: 16px;
    color: var(--text-secondary);
    margin-bottom: 15px;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: var(--border-color);
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    border-radius: 4px;
    transition: width 0.3s ease;
    width: 0%;
}

/* ===== 模态框样式 ===== */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(10px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
}

.modal.show {
    opacity: 1;
    visibility: visible;
}

.modal-content {
    background: var(--surface-color);
    border-radius: 20px;
    padding: 0;
    max-width: 90vw;
    max-height: 90vh;
    overflow: hidden;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
    transform: scale(0.9);
    transition: transform 0.3s ease;
}

.modal.show .modal-content {
    transform: scale(1);
}

.modal-header {
    padding: 20px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h3 {
    margin: 0;
    color: var(--text-primary);
}

.modal-close {
    background: none;
    border: none;
    font-size: 24px;
    cursor: pointer;
    color: var(--text-secondary);
    padding: 0;
    width: 30px;
    height: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: all 0.2s ease;
}

.modal-close:hover {
    background: var(--border-color);
}

.modal-body {
    padding: 20px;
}

/* ===== 主题选择器 ===== */
.theme-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 15px;
}

.theme-option {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
    padding: 15px;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.2s ease;
    border: 2px solid transparent;
}

.theme-option:hover {
    background: var(--tile-hover);
}

.theme-option.active {
    border-color: var(--primary-color);
    background: var(--tile-active);
}

.theme-preview {
    width: 60px;
    height: 60px;
    border-radius: 12px;
    border: 2px solid var(--border-color);
}

.modern-preview {
    background: linear-gradient(135deg, #007AFF, #5856D6);
}

.classic-preview {
    background: linear-gradient(135deg, #0078D4, #C0C0C0);
}

.dark-preview {
    background: linear-gradient(135deg, #0A84FF, #1C1C1E);
}

.rainbow-preview {
    background: linear-gradient(135deg, #FF6B6B, #4ECDC4, #45B7D1);
}

.theme-name {
    font-size: 14px;
    font-weight: 600;
    color: var(--text-primary);
}

/* ===== 完成统计 ===== */
.completion-stats {
    display: flex;
    flex-direction: column;
    gap: 15px;
    margin-bottom: 20px;
}

.stat-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 0;
    border-bottom: 1px solid var(--border-color);
}

.stat-row:last-child {
    border-bottom: none;
}

.modal-actions {
    display: flex;
    gap: 10px;
    justify-content: center;
}

/* ===== 说明面板 ===== */
.instructions {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: var(--surface-color);
    border-radius: 20px;
    padding: 30px;
    max-width: 500px;
    width: 90vw;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
}

.instructions.show {
    opacity: 1;
    visibility: visible;
}

.instructions h3 {
    margin-bottom: 20px;
    color: var(--text-primary);
    text-align: center;
}

.instruction-content {
    display: flex;
    flex-direction: column;
    gap: 15px;
    margin-bottom: 20px;
}

.instruction-item {
    display: flex;
    align-items: flex-start;
    gap: 12px;
}

.instruction-icon {
    font-size: 20px;
    flex-shrink: 0;
    margin-top: 2px;
}

.instruction-text {
    flex: 1;
    line-height: 1.5;
}

.instruction-text strong {
    color: var(--primary-color);
}

/* ===== 加载屏幕 ===== */
.loading-screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--background-color);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2000;
    transition: opacity 0.5s ease;
}

.loading-content {
    text-align: center;
}

.loading-spinner {
    width: 50px;
    height: 50px;
    border: 4px solid var(--border-color);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 20px;
}

.loading-text {
    font-size: 18px;
    color: var(--text-secondary);
}

/* ===== 动画 ===== */
@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

@keyframes hint-pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

@keyframes slide-in {
    from {
        transform: translateX(-100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

@keyframes slide-out {
    from {
        transform: translateX(0);
        opacity: 1;
    }
    to {
        transform: translateX(100%);
        opacity: 0;
    }
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateY(0);
    }
    40% {
        transform: translateY(-10px);
    }
    60% {
        transform: translateY(-5px);
    }
}

/* ===== 响应式设计 ===== */

/* 大屏幕 (1024px+) */
@media (min-width: 1024px) {
    .game-container {
        padding: 30px;
        gap: 30px;
    }
    
    .puzzle-grid {
        max-width: 450px;
    }
    
    .puzzle-tile {
        font-size: 1.8rem;
    }
    
    .puzzle-grid.size-5x5 .puzzle-tile {
        font-size: 1.4rem;
    }
}

/* 平板 (768px - 1023px) */
@media (max-width: 1023px) and (min-width: 768px) {
    .game-container {
        padding: 25px;
        gap: 25px;
    }
    
    .header-content {
        flex-direction: column;
        text-align: center;
    }
    
    .game-info {
        flex-direction: column;
        align-items: center;
        text-align: center;
    }
    
    .puzzle-grid {
        max-width: 350px;
    }
    
    .puzzle-tile {
        font-size: 1.4rem;
    }
    
    .puzzle-grid.size-5x5 .puzzle-tile {
        font-size: 1.1rem;
    }
}

/* 手机 (480px - 767px) */
@media (max-width: 767px) and (min-width: 480px) {
    .game-container {
        padding: 20px;
        gap: 20px;
    }
    
    .header-content {
        flex-direction: column;
        text-align: center;
        gap: 10px;
    }
    
    .game-title {
        font-size: 1.8rem;
    }
    
    .header-controls {
        justify-content: center;
    }
    
    .game-info {
        flex-direction: column;
        align-items: center;
        text-align: center;
        gap: 15px;
    }
    
    .info-section {
        flex-direction: column;
        gap: 15px;
    }
    
    .puzzle-grid {
        max-width: 300px;
    }
    
    .puzzle-tile {
        font-size: 1.2rem;
    }
    
    .puzzle-grid.size-5x5 .puzzle-tile {
        font-size: 0.9rem;
    }
    
    .game-controls {
        justify-content: center;
        flex-wrap: wrap;
    }
    
    .image-gallery {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* 小屏手机 (375px - 479px) */
@media (max-width: 479px) {
    .game-container {
        padding: 15px;
        gap: 15px;
    }
    
    .game-header {
        padding: 15px;
    }
    
    .game-title {
        font-size: 1.6rem;
    }
    
    .header-controls {
        width: 100%;
        justify-content: center;
    }
    
    .btn {
        padding: 8px 12px;
        font-size: 12px;
    }
    
    .game-info {
        padding: 15px;
        flex-direction: column;
        gap: 15px;
    }
    
    .info-section {
        flex-direction: column;
        gap: 10px;
        width: 100%;
    }
    
    .game-stats {
        justify-content: center;
        gap: 15px;
    }
    
    .game-controls {
        width: 100%;
        justify-content: center;
        flex-wrap: wrap;
    }
    
    .puzzle-container {
        padding: 15px;
    }
    
    .puzzle-grid {
        max-width: 280px;
    }
    
    .puzzle-tile {
        font-size: 1rem;
    }
    
    .puzzle-grid.size-5x5 .puzzle-tile {
        font-size: 0.8rem;
    }
    
    .modal-content {
        margin: 20px;
        max-width: calc(100vw - 40px);
    }
    
    .instructions {
        padding: 20px;
        max-width: calc(100vw - 40px);
    }
    
    .image-gallery {
        grid-template-columns: 1fr 1fr;
        gap: 10px;
    }
}

/* ===== 触摸设备优化 ===== */
@media (hover: none) and (pointer: coarse) {
    .puzzle-tile {
        min-height: 44px; /* iOS推荐的最小触摸目标 */
    }
    
    .btn {
        min-height: 44px;
        padding: 12px 16px;
    }
    
    .upload-btn {
        min-height: 44px;
    }
    
    /* 移除hover效果 */
    .puzzle-tile:hover,
    .btn:hover,
    .upload-btn:hover,
    .image-option:hover {
        transform: none;
        background: var(--tile-bg);
    }
    
    .btn-secondary:hover {
        background: var(--surface-color);
    }
}

/* ===== 高对比度模式支持 ===== */
@media (prefers-contrast: high) {
    :root {
        --border-color: #000000;
        --tile-border: #000000;
        --shadow-color: rgba(0, 0, 0, 0.5);
    }
}

/* ===== 减少动画模式支持 ===== */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    .loading-spinner {
        animation: none;
        border: 4px solid var(--primary-color);
    }
}

/* ===== 打印样式 ===== */
@media print {
    .game-container {
        background: white;
        color: black;
    }
    
    .header-controls,
    .game-controls,
    .modal,
    .instructions,
    .loading-screen {
        display: none !important;
    }
    
    .puzzle-grid {
        border: 2px solid black;
        background: white;
    }
    
    .puzzle-tile {
        background: white;
        border: 1px solid black;
    }
}