/* 毕达哥拉斯定理动画证明 - 简洁样式表 */

/* 全局样式 */
@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;500;600;700&display=swap');

:root {
    --primary-color: #2c5282;
    --secondary-color: #4a5568;
    --tertiary-color: #3182ce;
    --bg-color: #f7fafc;
    --card-bg: #ffffff;
    --text-color: #1a202c;
    --text-secondary: #718096;
    --border-radius: 12px;
    --transition-speed: 0.3s;
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
}

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

body {
    font-family: 'Poppins', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    overflow-x: hidden;
    transition: background-color var(--transition-speed) ease;
    -webkit-tap-highlight-color: transparent;
    touch-action: manipulation;
}

.container {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    max-width: 1280px;
    margin: 0 auto;
    padding: 20px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.05);
    background-color: var(--bg-color);
    border-radius: 20px;
}

/* 头部样式 */
header {
    text-align: center;
    padding: 24px 0;
    background-color: var(--primary-color);
    color: white;
    border-radius: var(--border-radius);
    margin-bottom: 24px;
    box-shadow: var(--shadow-md);
    position: relative;
}

header::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255,255,255,0.1) 0%, transparent 60%);
    z-index: 0;
}

header h1 {
    font-size: 2.2rem;
    font-weight: 600;
    margin-bottom: 12px;
    position: relative;
    z-index: 1;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

header h1::after {
    content: '';
    display: block;
    width: 100%;
    height: 2px;
    background: rgba(255, 255, 255, 0.5);
    margin: 8px auto 0;
}

header h1 span.author {
    display: inline-block;
    font-size: 1.4rem;
    font-weight: 500;
    color: #ffffff;
    text-shadow: 0 1px 3px rgba(0, 0, 0, 0.4);
    margin-left: 10px;
    padding: 4px 14px;
    border-radius: 20px;
    background: linear-gradient(135deg, rgba(79, 129, 189, 0.8) 0%, rgba(41, 82, 149, 0.9) 100%);
    vertical-align: middle;
    border: 1px solid rgba(255, 255, 255, 0.2);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.2), inset 0 1px 1px rgba(255, 255, 255, 0.2);
    transition: all 0.3s ease;
    transform-origin: left center;
    animation: authorGlow 3s infinite alternate;
}

header h1 span.author:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3), inset 0 1px 1px rgba(255, 255, 255, 0.3);
    background: linear-gradient(135deg, rgba(92, 151, 219, 0.9) 0%, rgba(52, 104, 186, 1) 100%);
}

@keyframes authorGlow {
    0% {
        box-shadow: 0 2px 10px rgba(0, 0, 0, 0.2), inset 0 1px 1px rgba(255, 255, 255, 0.2);
    }
    100% {
        box-shadow: 0 2px 15px rgba(79, 129, 189, 0.5), inset 0 1px 1px rgba(255, 255, 255, 0.2);
    }
}

.formula {
    font-size: 1.6rem;
    font-weight: 500;
    position: relative;
    z-index: 1;
    background: rgba(255, 255, 255, 0.1);
    display: inline-block;
    padding: 8px 24px;
    border-radius: 30px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

/* 主要内容区域 */
main {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.canvas-container {
    width: 100%;
    height: 420px;
    background-color: var(--card-bg);
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    position: relative;
    transition: transform var(--transition-speed) ease, box-shadow var(--transition-speed) ease;
}

.canvas-container:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

#theorem-canvas {
    width: 100%;
    height: 100%;
}

.explanation-container {
    background-color: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 24px;
    box-shadow: var(--shadow-md);
    transition: transform var(--transition-speed) ease;
}

.explanation-container:hover {
    transform: translateY(-3px);
}

.explanation {
    border-left: 4px solid var(--primary-color);
    padding-left: 18px;
    position: relative;
}

.explanation::before {
    content: '';
    position: absolute;
    left: -4px;
    top: 0;
    width: 4px;
    height: 40px;
    background-color: var(--primary-color);
    border-radius: 4px;
}

.explanation p {
    margin-bottom: 12px;
    font-size: 1.05rem;
    line-height: 1.7;
}

/* 底部控制区域 */
footer {
    margin-top: 24px;
}

.controls {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 18px;
    background-color: var(--card-bg);
    padding: 18px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
    margin-bottom: 18px;
    position: relative;
    overflow: hidden;
}

.controls::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: var(--primary-color);
}

button {
    padding: 10px 20px;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    transition: all var(--transition-speed) ease;
    box-shadow: var(--shadow-sm);
}

button::before {
    display: none;
}

button:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

button:active {
    transform: translateY(0);
    box-shadow: var(--shadow-sm);
}

button:disabled {
    background-color: #a0a0a0;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
    opacity: 0.7;
}

button#reset-btn {
    background-color: var(--secondary-color);
}

button#reset-btn:hover {
    box-shadow: 0 8px 20px rgba(251, 95, 130, 0.4), 
                0 0 0 2px rgba(251, 95, 130, 0.2);
}

button#prev-btn, button#next-btn {
    position: relative;
    padding-left: 30px;
    padding-right: 30px;
}

button#prev-btn::after {
    content: none;
}

button#next-btn::after {
    content: none;
}

.step-indicator {
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--primary-color);
    padding: 8px 16px;
    background-color: rgba(44, 82, 130, 0.1);
    border-radius: 6px;
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 80px;
}

.step-indicator::before {
    content: '步骤';
    position: absolute;
    top: -8px;
    font-size: 0.7rem;
    font-weight: 500;
    color: var(--text-secondary);
    background-color: var(--card-bg);
    padding: 0 4px;
    border-radius: 2px;
}

.copyright {
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-top: 10px;
    position: relative;
    padding-top: 15px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.copyright::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 2px;
    background: linear-gradient(90deg, transparent, var(--text-secondary), transparent);
}

/* 响应式设计 - 优化 */
@media (min-width: 768px) {
    main {
        flex-direction: row;
    }
    
    .canvas-container {
        flex: 3;
        height: 520px;
    }
    
    .explanation-container {
        flex: 2;
        max-height: 520px;
        overflow-y: auto;
        transition: all var(--transition-speed) ease;
    }
    
    .explanation-container::-webkit-scrollbar {
        width: 8px;
    }
    
    .explanation-container::-webkit-scrollbar-track {
        background: rgba(0, 0, 0, 0.05);
        border-radius: 10px;
    }
    
    .explanation-container::-webkit-scrollbar-thumb {
        background: rgba(58, 109, 240, 0.3);
        border-radius: 10px;
    }
    
    .explanation-container::-webkit-scrollbar-thumb:hover {
        background: rgba(58, 109, 240, 0.5);
    }
}

/* 平板设备 */
@media (max-width: 767px) {
    .container {
        padding: 15px;
        border-radius: 12px;
    }
    
    header {
        padding: 20px 0;
        margin-bottom: 20px;
    }
    
    header h1 {
        font-size: 1.6rem;
    }
    
    .formula {
        font-size: 1.2rem;
        padding: 6px 16px;
    }
    
    main {
        gap: 16px;
    }
    
    .canvas-container {
        height: 350px;
        -webkit-overflow-scrolling: touch;
    }
    
    .explanation-container {
        padding: 18px;
    }
    
    .explanation p {
        font-size: 1rem;
        line-height: 1.6;
    }
    
    .controls {
        flex-wrap: wrap;
        padding: 15px;
        gap: 12px;
        justify-content: center;
    }
    
    .step-indicator {
        min-width: 90px;
        order: -1;
        width: 100%;
        margin-bottom: 8px;
    }
    
    button#prev-btn, button#next-btn {
        padding-left: 15px;
        padding-right: 15px;
        flex: 1;
        max-width: calc(50% - 6px);
    }
    
    .explanation-header {
        font-size: 1rem;
    }
    
    .canvas-info {
        font-size: 0.75rem;
        padding: 6px 10px;
        top: 10px;
        right: 10px;
    }
    
    .social-links {
        gap: 12px;
    }
    
    .social-links a {
        width: 36px;
        height: 36px;
    }
    
    .social-links i {
        font-size: 1.1rem;
    }
    
    footer {
        margin-top: 16px;
    }
    
    button {
        padding: 10px 18px;
        font-size: 0.95rem;
        min-width: 100px;
        min-height: 42px;
        touch-action: manipulation;
    }
}

/* 手机设备 */
@media (max-width: 480px) {
    .container {
        padding: 12px;
        border-radius: 8px;
    }
    
    header {
        padding: 16px 0;
        margin-bottom: 16px;
        border-radius: 8px;
    }
    
    header h1 {
        font-size: 1.4rem;
        margin-bottom: 8px;
    }
    
    .formula {
        font-size: 1.1rem;
        padding: 5px 14px;
    }
    
    .canvas-container {
        height: calc(100vw * 0.8);
        border-radius: 8px;
        touch-action: manipulation;
    }
    
    canvas {
        touch-action: none;
    }
    
    .explanation-container {
        padding: 16px;
        border-radius: 8px;
        -webkit-overflow-scrolling: touch;
    }
    
    .explanation {
        padding-left: 14px;
    }
    
    .explanation p {
        font-size: 0.95rem;
        line-height: 1.5;
        margin-bottom: 10px;
    }
    
    .controls {
        padding: 16px;
        border-radius: 12px;
        display: grid;
        grid-template-columns: 1fr 1fr;
        grid-template-areas: 
            "indicator indicator"
            "prev next"
            "reset reset";
        gap: 12px;
        background: var(--bg-secondary);
        box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
        margin-bottom: 16px;
    }
    
    .step-indicator {
        grid-area: indicator;
        margin-bottom: 0;
    }
    
    button#prev-btn {
        grid-area: prev;
        height: 60px;
        display: flex;
        align-items: center;
        justify-content: center;
    }
    
    button#next-btn {
        grid-area: next;
        height: 60px;
        display: flex;
        align-items: center;
        justify-content: center;
    }
    
    button#reset-btn {
        grid-area: reset;
        margin-top: 0;
    }
    
    button {
        padding: 12px;
        font-size: 1rem;
        min-width: auto;
        border-radius: 8px;
        width: 100%;
        min-height: 48px;
        display: flex;
        align-items: center;
        justify-content: center;
        gap: 8px;
    }
    
    button i {
        font-size: 1.1rem;
    }
    
    .copyright {
        font-size: 0.8rem;
    }
    
    .tagline {
        font-size: 0.75rem;
    }
    
    .social-links {
        margin-top: 8px;
    }
    
    .social-links a {
        width: 32px;
        height: 32px;
    }
    
    .explanation-header {
        font-size: 0.95rem;
        padding-bottom: 8px;
        margin-bottom: 12px;
    }
    
    .explanation-header i {
        font-size: 1.1rem;
    }
    
    /* 增强触摸区域大小 */
    button, .social-links a {
        position: relative;
    }
    
    button::after, .social-links a::after {
        content: '';
        position: absolute;
        top: -5px;
        left: -5px;
        right: -5px;
        bottom: -5px;
        z-index: -1;
    }
    
    /* 防止表单元素放大 */
    input, button, select, textarea {
        font-size: 16px;
    }
    
    /* 优化触控反馈 */
    button:active {
        transform: scale(0.98);
        transition: transform 0.1s;
    }
}

/* 超小屏幕设备 */
@media (max-width: 360px) {
    .container {
        padding: 8px;
    }
    
    header h1 {
        font-size: 1.3rem;
    }
    
    .formula {
        font-size: 1rem;
        padding: 4px 12px;
    }
    
    .canvas-container {
        height: calc(100vw * 0.9);
    }
    
    .controls {
        padding: 10px 8px;
    }
    
    button {
        padding: 8px 10px;
        font-size: 0.85rem;
    }
    
    .step-indicator {
        font-size: 1rem;
        min-width: 80px;
    }
    
    .explanation p {
        font-size: 0.9rem;
    }
}

/* 高级视觉效果和动画 */
.canvas-container {
    position: relative;
    overflow: hidden;
}

.canvas-container::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background-color: var(--primary-color);
    z-index: 2;
}

.canvas-container::after {
    display: none;
}

@keyframes pulse {
    0% {
        box-shadow: 0 0 0 0 rgba(44, 82, 130, 0.4);
    }
    70% {
        box-shadow: 0 0 0 5px rgba(44, 82, 130, 0);
    }
    100% {
        box-shadow: 0 0 0 0 rgba(44, 82, 130, 0);
    }
}

button:focus {
    outline: none;
    animation: pulse 1.5s infinite;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.explanation p {
    animation: fadeIn 0.5s ease-out forwards;
    opacity: 0;
}

.explanation p:nth-child(1) {
    animation-delay: 0.1s;
}

.explanation p:nth-child(2) {
    animation-delay: 0.3s;
}

.explanation p:nth-child(3) {
    animation-delay: 0.5s;
}

/* 暗黑模式支持 */
@media (prefers-color-scheme: dark) {
    :root {
        --bg-color: #171923;
        --card-bg: #2d3748;
        --text-color: #e2e8f0;
        --text-secondary: #a0aec0;
        --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.2);
        --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.3);
        --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.4);
    }
    
    .explanation::before {
        height: 60px;
    }
    
    .step-indicator {
        background-color: rgba(58, 109, 240, 0.2);
    }
    
    .step-indicator::before {
        background-color: var(--card-bg);
    }
    
    .explanation-header {
        border-bottom-color: rgba(255, 255, 255, 0.1);
    }
    
    .social-links a {
        background: rgba(255, 255, 255, 0.1);
    }
}

/* canvas信息提示 */
.canvas-info {
    position: absolute;
    top: 15px;
    right: 15px;
    background: rgba(26, 32, 44, 0.7);
    color: white;
    padding: 6px 10px;
    border-radius: 6px;
    font-size: 0.8rem;
    opacity: 0;
    transform: translateY(-5px);
    transition: all var(--transition-speed) ease;
    display: flex;
    align-items: center;
    gap: 6px;
}

.canvas-container:hover .canvas-info {
    opacity: 1;
    transform: translateY(0);
}

.canvas-info i {
    color: #e2e8f0;
    font-size: 1.1rem;
}

/* 说明区域标题 */
.explanation-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
    font-weight: 500;
    color: var(--primary-color);
    font-size: 1.1rem;
}

.explanation-header i {
    font-size: 1.3rem;
}

/* 按钮图标 */
button i {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    vertical-align: middle;
    margin-top: -2px;
}

button#prev-btn i {
    margin-right: 5px;
}

button#next-btn i {
    margin-left: 5px;
}

button#reset-btn i {
    margin-right: 5px;
    font-size: 1.1rem;
}

/* 重写箭头图标（替换文本箭头） */
button#prev-btn::after,
button#next-btn::after {
    content: none;
}

/* 社交分享链接 */
.social-links {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-top: 10px;
}

.social-links a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    border-radius: 4px;
    background: rgba(0, 0, 0, 0.05);
    color: var(--text-secondary);
    transition: all var(--transition-speed) ease;
    text-decoration: none;
}

.social-links a:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-2px);
}

.social-links i {
    font-size: 1.3rem;
}

/* 添加强调效果 */
.formula sup {
    color: rgba(255, 255, 255, 0.9);
    font-weight: 700;
    position: relative;
    top: -3px;
    font-size: 0.8em;
}

/* 步骤切换动画增强 */
.canvas-container canvas {
    transition: transform 0.3s ease, opacity 0.3s ease;
}

/* 标语样式 */
.tagline {
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-style: italic;
    margin-top: 4px;
    margin-bottom: 8px;
    opacity: 0.8;
}

/* 全局样式补充 */
html {
    scroll-behavior: smooth;
}