/* 主题变量 */
:root {
    /* 明亮主题 */
    --light-primary: #ffffff;
    --light-secondary: #f8f9fa;
    --light-accent: #007bff;
    --light-text: #212529;
    --light-shadow: rgba(0, 0, 0, 0.1);
    
    /* 暗色主题 */
    --dark-primary: #1a1a1a;
    --dark-secondary: #2d2d2d;
    --dark-accent: #00ff9d;
    --dark-text: #ffffff;
    --dark-shadow: rgba(0, 255, 157, 0.2);
}

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

body {
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    font-family: 'Arial', sans-serif;
    transition: all 0.3s ease;
}

body.light-theme {
    color: var(--light-text);
}

body.dark-theme {
    color: var(--dark-text);
}

/* 背景容器 */
.background-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
}

.background {
    position: absolute;
    width: 100%;
    height: 100%;
}

/* 粒子层 */
.particles-layer {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
    pointer-events: none; /* 允许点击穿透到下层元素 */
}

/* 主题切换按钮 */
.theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 100;
}

#theme-toggle-btn {
    background: rgba(255, 255, 255, 0.2);
    border: none;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    font-size: 24px;
    cursor: pointer;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.light-theme #theme-toggle-btn {
    background: rgba(0, 0, 0, 0.05);
    color: var(--light-accent);
}

.dark-theme #theme-toggle-btn {
    background: rgba(255, 255, 255, 0.1);
    color: var(--dark-accent);
}

#theme-toggle-btn:hover {
    transform: rotate(45deg);
}

/* 计算器主体 */
.calculator {
    width: 360px;
    border-radius: 24px;
    padding: 25px;
    transition: all 0.3s ease;
    z-index: 10;
}

.light-theme .calculator {
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(10px);
    box-shadow: 
        0 10px 30px var(--light-shadow),
        0 1px 8px rgba(0,0,0,0.05);
}

.dark-theme .calculator {
    background: rgba(26, 26, 26, 0.85);
    backdrop-filter: blur(10px);
    box-shadow: 
        0 10px 30px var(--dark-shadow),
        0 1px 8px rgba(0,0,0,0.2);
}

/* 计算器头部 */
.calculator-header {
    display: flex;
    justify-content: flex-end;
    margin-bottom: 20px;
}

#mode-selector {
    padding: 8px 12px;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.light-theme #mode-selector {
    background: var(--light-secondary);
    border: 1px solid var(--light-secondary);
    color: var(--light-text);
}

.dark-theme #mode-selector {
    background: var(--dark-secondary);
    border: 1px solid var(--dark-secondary);
    color: var(--dark-text);
}

/* 显示屏 */
.display {
    border-radius: 16px;
    padding: 20px;
    margin-bottom: 25px;
    text-align: right;
    transition: all 0.3s ease;
}

.light-theme .display {
    background: var(--light-secondary);
}

.dark-theme .display {
    background: var(--dark-secondary);
}

.history {
    font-size: 0.8em;
    min-height: 20px;
    margin-bottom: 5px;
}

.light-theme .history {
    color: #666;
}

.dark-theme .history {
    color: #aaa;
}

.current {
    font-size: 2em;
    word-wrap: break-word;
    min-height: 50px;
}

.light-theme .current {
    color: var(--light-text);
}

.dark-theme .current {
    color: var(--dark-text);
}

/* 错误状态 */
.error {
    color: #d63031 !important;
    animation: shake 0.5s linear;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    75% { transform: translateX(5px); }
}

/* 按键网格 */
.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
}

/* 按键样式 */
button {
    border-radius: 16px;
    padding: 18px;
    font-size: 1.2em;
    font-weight: 500;
    border: none;
    transition: all 0.2s ease;
    cursor: pointer;
    user-select: none;
}

.light-theme button {
    background: var(--light-secondary);
    color: var(--light-text);
}

.dark-theme button {
    background: var(--dark-secondary);
    color: var(--dark-text);
}

/* 操作符按钮 */
.light-theme .operator {
    background: var(--light-accent);
    color: white;
}

.dark-theme .operator {
    background: var(--dark-accent);
    color: var(--dark-primary);
}

/* 等号按钮 */
.light-theme .equals {
    background: var(--light-accent);
    color: white;
}

.dark-theme .equals {
    background: var(--dark-accent);
    color: var(--dark-primary);
}

/* 清除按钮 */
.clear {
    background: #dc3545 !important;
    color: white !important;
}

/* 科学计算器按键 */
.scientific-buttons {
    margin-top: 12px;
    padding-top: 12px;
}

.light-theme .scientific-buttons {
    border-top: 1px solid var(--light-secondary);
}

.dark-theme .scientific-buttons {
    border-top: 1px solid var(--dark-secondary);
}

.light-theme .scientific {
    background: #6c757d;
    color: white;
}

.dark-theme .scientific {
    background: #3498db;
    color: white;
}

/* 按键悬停效果 */
button:hover {
    transform: scale(0.95);
    opacity: 0.9;
}

/* 按键点击效果 */
button:active {
    transform: scale(0.9);
}

/* 响应式设计 */
@media (max-width: 400px) {
    .calculator {
        width: 95%;
        margin: 10px;
        padding: 15px;
    }

    button {
        padding: 15px;
        font-size: 1em;
    }
}

/* 动画效果 */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.calculator {
    animation: fadeIn 0.5s ease;
}

@keyframes pulse {
    0% { opacity: 0.5; }
    50% { opacity: 1; }
    100% { opacity: 0.5; }
}

.tech-line {
    animation: pulse 3s infinite;
}