/* 全局变量 */
:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary: #64748b;
    --success: #22c55e;
    --background: #f8fafc;
    --surface: #ffffff;
    --text: #1e293b;
    --text-secondary: #64748b;
    --border: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1);
    --radius: 0.5rem;
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    background-color: var(--background);
    color: var(--text);
    line-height: 1.5;
}

/* 布局 */
.app-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* 导航栏 */
.navbar {
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: 1rem;
    position: sticky;
    top: 0;
    z-index: 100;
}

.navbar-content {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 1rem;
    gap: 2rem;
}

.logo {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--primary);
    text-decoration: none;
    white-space: nowrap;
}

.nav-links {
    display: flex;
    gap: 2rem;
    align-items: center;
    margin-right: auto;
    padding-left: 2rem;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: color var(--transition);
    white-space: nowrap;
}

.nav-link:hover {
    color: var(--primary);
}

.nav-link.active {
    color: var(--primary);
}

/* 主要内容区 */
.main-content {
    flex: 1;
    padding: 2rem 1rem;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* 卡片组件 */
.card {
    background: var(--surface);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 2rem;
    max-width: 800px;
    margin: 0 auto;
}

/* 表单元素 */
.form-group {
    margin-bottom: 1.5rem;
}

.form-label {
    display: block;
    font-weight: 500;
    margin-bottom: 0.5rem;
    color: var(--text);
}

.form-control {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    background: var(--surface);
    color: var(--text);
    transition: all var(--transition);
}

.form-control:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-text {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-top: 0.5rem;
}

/* 高级选项动画 */
#customOptions {
    max-height: 0;
    overflow: hidden;
    opacity: 0;
    transition: max-height var(--transition),
                opacity var(--transition),
                margin var(--transition);
    margin-top: 0;
}

#customOptions.show {
    max-height: 300px;
    opacity: 1;
    margin-top: 1.5rem;
}

/* 按钮 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius);
    font-weight: 500;
    transition: all var(--transition);
    cursor: pointer;
    border: none;
    gap: 0.5rem;
}

.btn-primary {
    background: var(--primary);
    color: white;
}

.btn-primary:hover {
    background: var(--primary-dark);
}

.btn-outline {
    background: transparent;
    border: 1px solid var(--primary);
    color: var(--primary);
}

.btn-outline:hover {
    background: rgba(37, 99, 235, 0.1);
}

/* 结果展示 */
.result-section {
    margin-top: 2rem;
    padding: 1.5rem;
    background: var(--background);
    border-radius: var(--radius);
    border: 1px solid var(--border);
}

.short-url {
    font-family: monospace;
    font-size: 1.125rem;
    color: var(--primary);
    padding: 1rem;
    background: var(--surface);
    border-radius: var(--radius);
    margin: 1rem 0;
    word-break: break-all;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .navbar-content {
        flex-direction: column;
        gap: 1rem;
    }

    .nav-links {
        flex-direction: column;
        gap: 1rem;
        padding-left: 0;
        width: 100%;
        text-align: center;
    }

    .language-switcher {
        margin-left: 0;
        width: 100%;
    }

    .language-button {
        width: 100%;
        justify-content: center;
    }

    .language-options {
        width: 100%;
        text-align: center;
    }
}

/* 工具类 */
.hidden {
    display: none !important;
}

.flex {
    display: flex;
}

.items-center {
    align-items: center;
}

.justify-between {
    justify-content: space-between;
}

.gap-2 {
    gap: 0.5rem;
}

.mt-4 {
    margin-top: 1rem;
}

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

.font-semibold {
    font-weight: 600;
}

/* 语言切换器 */
.language-switcher {
    position: relative;
    margin-left: 2rem;
}

.language-button {
    background: none;
    border: 1px solid var(--border);
    padding: 0.5rem 1rem;
    border-radius: var(--radius);
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.875rem;
    transition: all var(--transition);
}

.language-button:hover {
    border-color: var(--primary);
    color: var(--primary);
}

.language-options {
    position: absolute;
    top: 100%;
    right: 0;
    margin-top: 0.5rem;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all var(--transition);
    min-width: 120px;
    z-index: 100;
}

.language-options.show {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.language-option {
    padding: 0.75rem 1rem;
    cursor: pointer;
    transition: all var(--transition);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.language-option:hover {
    background: var(--background);
    color: var(--primary);
}

.language-option.active {
    color: var(--primary);
    background: var(--background);
}