/* ===== 联合公社 - 公共基础样式 ===== */

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

/* 设计变量 */
:root {
    --primary: #4f6ef7;
    --primary-dark: #3b5de7;
    --primary-light: #eef1fe;
    --accent-red: #f06449;
    --accent-orange: #f5a623;
    --accent-blue: #4f9cf7;
    --bg: #f5f7fb;
    --card-bg: #ffffff;
    --text: #1e293b;
    --text-secondary: #5a6a85;
    --text-muted: #94a3b8;
    --border: #e8ecf4;
    --shadow-sm: 0 2px 8px rgba(79,110,247,0.06);
    --shadow-md: 0 8px 24px rgba(79,110,247,0.08);
    --shadow-lg: 0 16px 40px rgba(79,110,247,0.12);
}

body {
    font-family: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
    background-color: var(--bg);
    color: var(--text);
    line-height: 1.6;
    overflow-x: hidden;
}

/* ===== 顶部导航栏 ===== */
.top-bar {
    background: rgba(255,255,255,0.85);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    color: var(--text);
    padding: 0.75rem 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 1px 0 var(--border);
    transition: box-shadow 0.3s;
}
.top-bar.scrolled {
    box-shadow: 0 4px 20px rgba(79,110,247,0.08);
}

/* Logo */
.logo {
    font-size: 1.4rem;
    font-weight: 700;
    letter-spacing: 1px;
    background: linear-gradient(135deg, var(--primary), var(--accent-blue));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}
.logo-icon {
    width: 28px;
    height: 28px;
    border-radius: 8px;
    background: linear-gradient(135deg, var(--primary), var(--accent-blue));
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 0.8rem;
    font-weight: 800;
    flex-shrink: 0;
}

/* 返回按钮 */
.back-btn {
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem 0.8rem;
    border-radius: 10px;
    transition: background 0.2s;
    display: flex;
    align-items: center;
    gap: 0.3rem;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--primary);
    text-decoration: none;
}
.back-btn:hover {
    background-color: var(--primary-light);
}
.back-arrow {
    transition: transform 0.2s;
}
.back-btn:hover .back-arrow {
    transform: translateX(-3px);
}

/* 汉堡菜单按钮 */
.menu-btn {
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 10px;
    transition: background 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
}
.menu-btn:hover {
    background-color: var(--primary-light);
}
.menu-icon {
    width: 24px;
    height: 18px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}
.menu-icon span {
    display: block;
    height: 2.5px;
    background: var(--primary);
    border-radius: 3px;
    transition: 0.3s cubic-bezier(0.4,0,0.2,1);
}
.menu-btn.active .menu-icon span:nth-child(1) {
    transform: translateY(7.75px) rotate(45deg);
}
.menu-btn.active .menu-icon span:nth-child(2) {
    opacity: 0;
    transform: scaleX(0);
}
.menu-btn.active .menu-icon span:nth-child(3) {
    transform: translateY(-7.75px) rotate(-45deg);
}

/* 下拉菜单 */
.dropdown-container {
    position: relative;
}
.dropdown-menu {
    position: absolute;
    top: 50px;
    right: 0;
    background-color: white;
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
    width: 180px;
    overflow: hidden;
    z-index: 200;
    opacity: 0;
    transform: translateY(-8px) scale(0.96);
    pointer-events: none;
    transition: opacity 0.25s cubic-bezier(0.4,0,0.2,1), transform 0.25s cubic-bezier(0.4,0,0.2,1);
    border: 1px solid var(--border);
}
.dropdown-menu.show {
    opacity: 1;
    transform: translateY(0) scale(1);
    pointer-events: auto;
}
.dropdown-item {
    padding: 0.8rem 1.25rem;
    font-size: 0.95rem;
    color: var(--text);
    cursor: pointer;
    transition: all 0.15s;
    border-bottom: 1px solid #f5f7fb;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}
.dropdown-item:last-child {
    border-bottom: none;
}
.dropdown-item:hover {
    background-color: var(--primary-light);
    color: var(--primary);
}
.dropdown-item-icon {
    font-size: 1rem;
    width: 20px;
    text-align: center;
}

/* ===== 主内容区 ===== */
.container {
    max-width: 960px;
    margin: 0 auto;
    padding: 2rem 1.5rem 4rem;
}

/* ===== 页脚 ===== */
footer {
    text-align: center;
    padding: 2.5rem 2rem;
    color: var(--text-muted);
    font-size: 0.8rem;
    border-top: 1px solid var(--border);
    margin-top: 2rem;
}
footer a {
    color: var(--primary);
    text-decoration: none;
}

/* ===== 关键帧动画 ===== */
@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-15px); }
}
@keyframes heroGradient {
    0%, 100% { background-position: 0% center; }
    50% { background-position: 100% center; }
}
@keyframes fadeSlideUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ===== 响应式 ===== */
@media (max-width: 768px) {
    .container {
        padding: 1rem 1rem 2rem;
    }
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        transition-duration: 0.01ms !important;
    }
}