/* ==================== CSS 变量系统 ==================== */
:root {
    --primary: #667eea;
    --primary-dark: #5a67d8;
    --secondary: #764ba2;
    --accent: #f093fb;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    
    --bg-primary: #f5f7fa;
    --bg-secondary: #e4e8ec;
    --bg-card: #ffffff;
    --bg-input: #ffffff;
    
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;
    
    --border-color: #e2e8f0;
    --shadow-sm: 0 2px 8px rgba(0,0,0,0.06);
    --shadow-md: 0 8px 24px rgba(0,0,0,0.08);
    --shadow-lg: 0 20px 60px rgba(0,0,0,0.12);
    --shadow-glow: 0 0 40px rgba(102, 126, 234, 0.3);
    
    --radius-sm: 12px;
    --radius-md: 20px;
    --radius-lg: 28px;
    
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

/* 深色模式 */
[data-theme="dark"] {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-card: #1e293b;
    --bg-input: #334155;
    
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #64748b;
    
    --border-color: #334155;
    --shadow-sm: 0 2px 8px rgba(0,0,0,0.3);
    --shadow-md: 0 8px 24px rgba(0,0,0,0.4);
    --shadow-lg: 0 20px 60px rgba(0,0,0,0.5);
}

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

body {
    font-family: system-ui, -apple-system, 'Segoe UI', 'Microsoft YaHei', sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    transition: background var(--transition-normal), color var(--transition-normal);
    overflow-x: hidden;
}

/* 动态背景 */
.animated-bg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: -1;
    overflow: hidden;
}

.bg-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.5;
    animation: float 20s infinite ease-in-out;
}

.bg-orb:nth-child(1) {
    width: 600px;
    height: 600px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    top: -200px;
    right: -200px;
    animation-delay: 0s;
}

.bg-orb:nth-child(2) {
    width: 400px;
    height: 400px;
    background: linear-gradient(135deg, var(--accent), var(--primary));
    bottom: -100px;
    left: -100px;
    animation-delay: -7s;
}

@keyframes float {
    0%, 100% { transform: translate(0, 0) scale(1); }
    25% { transform: translate(50px, -50px) scale(1.1); }
    50% { transform: translate(-30px, 30px) scale(0.9); }
    75% { transform: translate(40px, 40px) scale(1.05); }
}

/* ==================== 顶部导航 ==================== */
.top-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 0;
    margin-bottom: 20px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.3rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-decoration: none;
}

.logo:hover {
    opacity: 0.9;
}

.nav-actions {
    display: flex;
    gap: 12px;
    align-items: center;
}

.theme-toggle {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    border: 2px solid var(--border-color);
    background: var(--bg-card);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    transition: all var(--transition-fast);
}

.theme-toggle:hover {
    transform: scale(1.1);
    border-color: var(--primary);
}

/* ==================== 容器 ==================== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px 16px 40px;
    position: relative;
    z-index: 1;
}

/* ==================== 卡片样式 ==================== */
.card {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    padding: 28px;
    margin-bottom: 24px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-normal);
    animation: fadeInUp 0.5s ease-out;
    animation-fill-mode: both;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.card-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 20px;
    padding-bottom: 16px;
    border-bottom: 2px solid var(--border-color);
}

.card-header h2 {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 8px;
}

.card-icon {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.3rem;
}

/* ==================== 输入组件 ==================== */
.input-group {
    margin-bottom: 16px;
}

.input-label {
    display: block;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 8px;
    font-size: 0.9rem;
}

.input-field {
    width: 100%;
    padding: 14px 16px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--bg-input);
    color: var(--text-primary);
    font-size: 1rem;
    font-weight: 500;
    transition: all var(--transition-fast);
    outline: none;
}

.input-field:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(102, 126, 234, 0.1);
}

textarea.input-field {
    min-height: 120px;
    resize: vertical;
    font-family: 'Consolas', 'Monaco', monospace;
}

/* ==================== 按钮 ==================== */
.btn {
    padding: 14px 28px;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    display: inline-flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 25px rgba(102, 126, 234, 0.5);
}

.btn-secondary {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

.btn-secondary:hover {
    border-color: var(--primary);
    color: var(--primary);
}

/* ==================== 结果面板 ==================== */
.result-panel {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: var(--radius-lg);
    padding: 24px;
    color: white;
    margin-top: 20px;
}

.result-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 0;
    border-bottom: 1px solid rgba(255,255,255,0.15);
}

.result-row:last-child {
    border-bottom: none;
    margin-top: 8px;
    padding-top: 16px;
}

.result-label {
    font-size: 0.95rem;
    opacity: 0.9;
}

.result-value {
    font-size: 1.3rem;
    font-weight: 700;
}

.result-highlight {
    font-size: 2rem;
    text-shadow: 0 4px 20px rgba(0,0,0,0.3);
}

/* ==================== 工具卡片网格 ==================== */
.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 16px;
    margin-top: 24px;
}

.tool-card {
    background: var(--bg-card);
    border-radius: var(--radius-md);
    padding: 20px;
    text-align: center;
    border: 2px solid var(--border-color);
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
    color: inherit;
    display: block;
}

.tool-card:hover {
    border-color: var(--primary);
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.tool-icon {
    font-size: 2.5rem;
    margin-bottom: 12px;
}

.tool-name {
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.tool-desc {
    font-size: 0.8rem;
    color: var(--text-muted);
}

/* ==================== 响应式设计 ==================== */
@media (max-width: 768px) {
    .container {
        padding: 12px 10px 32px;
    }
    
    .card {
        padding: 20px 16px;
        border-radius: var(--radius-md);
    }
    
    .tools-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .result-highlight {
        font-size: 1.5rem;
    }
}