/* =========================================
   HelloWorld 全站公共样式
   包含：Reset、CSS变量、导航栏、按钮、页脚、移动端菜单
   页面特有样式保留在各页面的 <style> 中
   ========================================= */

/* ===== Reset & Base ===== */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary: #025BF8;
    --primary-light: #ECF5FF;
    --primary-hover: #0148cc;
    --text-primary: #303133;
    --text-regular: #606266;
    --text-secondary: #909399;
    --text-placeholder: #C0C4CC;
    --border-color: #DCDFE6;
    --bg-white: #FFFFFF;
    --bg-light: #F5F7FA;
    --shadow-card: 0 2px 12px 0 rgba(0, 0, 0, 0.1);
    --radius-sm: 20px;
    --radius-lg: 43px;
    --radius-card: 8px;
    --transition: all 0.3s cubic-bezier(0.645, 0.045, 0.355, 1);
    --max-width: 1200px;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
    font-size: 14px;
    color: var(--text-primary);
    line-height: 1.6;
    background: var(--bg-white);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

a {
    text-decoration: none;
    color: inherit;
}

ul, ol {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

button {
    border: none;
    cursor: pointer;
    font-family: inherit;
    outline: none;
}

/* ===== Navbar ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
    transition: var(--transition);
}

.navbar.scrolled {
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
}

.navbar-inner {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 60px;
}

.navbar-logo {
    display: flex;
    align-items: center;
    cursor: pointer;
}

.navbar-logo img {
    height: 39px;
}

.navbar-menu {
    display: flex;
    align-items: center;
    gap: 32px;
}

.navbar-menu a {
    font-size: 14px;
    color: var(--text-primary);
    transition: var(--transition);
    position: relative;
    padding: 4px 0;
}

.navbar-menu a:hover,
.navbar-menu a.active {
    color: var(--primary);
}

.navbar-menu a.active::after {
    content: '';
    position: absolute;
    bottom: -18px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--primary);
}

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

/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    font-weight: 500;
    border-radius: var(--radius-sm);
    padding: 7px 15px;
    transition: var(--transition);
    white-space: nowrap;
    line-height: 1;
    height: 36px;
}

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

.btn-outline:hover {
    background: #d9ecff;
}

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

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

.btn-large {
    border-radius: var(--radius-lg);
    padding: 12px 23px;
    font-size: 16px;
    height: 48px;
}

.btn-xl {
    border-radius: var(--radius-lg);
    padding: 14px 40px;
    font-size: 18px;
    height: 54px;
}

/* ===== Mobile Menu Button ===== */
.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 4px;
    z-index: 1001;
}

.mobile-menu-btn span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    transition: var(--transition);
    border-radius: 2px;
}

.mobile-menu-btn.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.mobile-menu-btn.active span:nth-child(2) {
    opacity: 0;
}

.mobile-menu-btn.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* ===== Footer ===== */
.footer {
    background: #1a1a2e;
    color: #fff;
    padding: 60px 20px 30px;
}

.footer-inner {
    max-width: var(--max-width);
    margin: 0 auto;
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1.5fr;
    gap: 40px;
}

.footer-col h4 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 24px;
    color: #fff;
}

.footer-col ul li {
    margin-bottom: 12px;
}

.footer-col ul li a {
    color: #B0B3BF;
    font-size: 14px;
    transition: var(--transition);
}

.footer-col ul li a:hover {
    color: #fff;
}

.footer-contact-cards {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.footer-contact-card {
    background: rgba(255, 255, 255, 0.08);
    border-radius: var(--radius-card);
    padding: 16px;
    text-align: center;
    min-width: 120px;
    transition: var(--transition);
}

.footer-contact-card:hover {
    background: rgba(255, 255, 255, 0.12);
}

.footer-contact-card img {
    width: 100px;
    height: 100px;
    margin: 0 auto 8px;
    border-radius: 4px;
}

.footer-contact-card span {
    font-size: 13px;
    color: #B0B3BF;
}

.footer-bottom {
    max-width: var(--max-width);
    margin: 40px auto 0;
    padding-top: 24px;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    display: flex;
    align-items: center;
    justify-content: space-between;
    color: #6B6F7D;
    font-size: 13px;
}

/* ===== Responsive: Navbar & Footer ===== */
@media (max-width: 768px) {
    .navbar-menu {
        position: fixed;
        top: 60px;
        left: 0;
        right: 0;
        background: #fff;
        flex-direction: column;
        padding: 20px;
        gap: 16px;
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
        transform: translateY(-110%);
        transition: transform 0.3s ease;
        z-index: 999;
    }

    .navbar-menu.open {
        transform: translateY(0);
    }

    .navbar-menu a.active::after {
        display: none;
    }

    .mobile-menu-btn {
        display: flex;
    }

    .footer-inner {
        grid-template-columns: 1fr;
    }

    .footer-bottom {
        flex-direction: column;
        gap: 12px;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .navbar-actions .btn {
        padding: 6px 12px;
        font-size: 13px;
        height: 32px;
    }
}