/* =========================================================
   共享组件样式 - ProtonVPN Edition IIIII (深海蓝主题)
   包含：CSS变量、按钮、导航栏、页脚、卡片、动画等共用元素
   ========================================================= */

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

:root {
    --primary: #0099ff;
    --primary-dark: #0077cc;
    --secondary: #00ffd5;
    --dark: #0a0e27;
    --darker: #050816;
    --light: #ffffff;
    --gray: #8b92b8;
    --gradient: linear-gradient(135deg, #0099ff 0%, #00ffd5 100%);
    --shadow-glow: 0 8px 25px rgba(0, 153, 255, 0.4);
}

html { scroll-behavior: smooth; }

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
    background: var(--darker);
    color: var(--light);
    line-height: 1.6;
    overflow-x: hidden;
}

a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; display: block; }

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.highlight {
    background: var(--gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.section-title {
    font-size: 2.5rem;
    text-align: center;
    margin-bottom: 50px;
    font-weight: 700;
}

/* ========== 导航栏 ========== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(10, 14, 39, 0.9);
    backdrop-filter: blur(15px);
    -webkit-backdrop-filter: blur(15px);
    z-index: 1000;
    border-bottom: 1px solid rgba(0, 153, 255, 0.2);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 15px 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.4rem;
    font-weight: 700;
}

.logo img {
    width: 36px;
    height: 36px;
    border-radius: 8px;
    object-fit: cover;
}

.nav-menu {
    display: flex;
    gap: 30px;
}

.nav-menu a {
    color: var(--light);
    font-weight: 500;
    transition: color 0.3s;
    position: relative;
    padding-bottom: 5px;
}

.nav-menu a:hover,
.nav-menu a.active {
    color: var(--secondary);
}

.nav-menu a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient);
    transition: width 0.3s;
}

.nav-menu a:hover::after,
.nav-menu a.active::after { width: 100%; }

.btn-login {
    padding: 8px 24px;
    background: var(--gradient);
    border-radius: 25px;
    font-weight: 600;
    transition: transform 0.3s, box-shadow 0.3s;
}

.btn-login:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-glow);
}

.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background: var(--light);
    border-radius: 3px;
    transition: 0.3s;
}

/* ========== 语言切换器 ========== */
.nav-actions {
    display: flex;
    align-items: center;
    gap: 15px;
}

.lang-switcher {
    position: relative;
}

.lang-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 8px 14px;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 20px;
    color: var(--light);
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.3s;
    font-family: inherit;
}

.lang-btn:hover {
    background: rgba(0, 153, 255, 0.2);
    border-color: var(--primary);
}

.lang-btn .flag {
    font-size: 1.1rem;
}

.lang-btn .arrow {
    font-size: 0.7rem;
    transition: transform 0.3s;
}

.lang-switcher.open .lang-btn .arrow {
    transform: rotate(180deg);
}

.lang-dropdown {
    position: absolute;
    top: calc(100% + 8px);
    right: 0;
    background: rgba(10, 14, 39, 0.98);
    backdrop-filter: blur(15px);
    border: 1px solid rgba(0, 153, 255, 0.3);
    border-radius: 12px;
    padding: 8px;
    min-width: 160px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all 0.3s;
    z-index: 1001;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
}

.lang-switcher.open .lang-dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.lang-option {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 12px;
    border-radius: 8px;
    cursor: pointer;
    transition: background 0.2s;
    font-size: 0.9rem;
    color: var(--light);
}

.lang-option:hover {
    background: rgba(0, 153, 255, 0.2);
}

.lang-option.active {
    background: rgba(0, 153, 255, 0.3);
    color: var(--secondary);
}

.lang-option .flag {
    font-size: 1.2rem;
}

/* ========== 按钮 ========== */
.btn {
    padding: 14px 32px;
    border-radius: 30px;
    font-weight: 600;
    transition: all 0.3s;
    display: inline-block;
    cursor: pointer;
    border: none;
    font-size: 1rem;
}

.btn-primary {
    background: var(--gradient);
    color: var(--light);
    box-shadow: var(--shadow-glow);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 12px 35px rgba(0, 153, 255, 0.5);
}

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

.btn-secondary:hover {
    background: var(--primary);
    transform: translateY(-3px);
}

.btn-outline {
    background: transparent;
    border: 2px solid var(--gray);
    color: var(--light);
}

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

/* ========== 页脚 ========== */
.footer {
    padding: 60px 20px 30px;
    background: rgba(5, 8, 22, 0.7);
    border-top: 1px solid rgba(0, 153, 255, 0.2);
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 15px;
}

.footer-logo img {
    width: 32px;
    height: 32px;
    border-radius: 8px;
}

.footer-col p { color: var(--gray); }

.footer-col h4 {
    margin-bottom: 15px;
    font-size: 1.1rem;
}

.footer-col li { padding: 5px 0; }

.footer-col a {
    color: var(--gray);
    transition: color 0.3s;
}

.footer-col a:hover { color: var(--secondary); }

.footer-bottom {
    text-align: center;
    padding-top: 25px;
    border-top: 1px solid rgba(0, 153, 255, 0.1);
    color: var(--gray);
    font-size: 0.9rem;
}

/* ========== 进入动画 ========== */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}

.reveal.is-visible {
    opacity: 1;
    transform: translateY(0);
}

/* ========== 友情链接 ========== */
.friend-links {
    max-width: 1200px;
    margin: 40px auto 0;
    padding: 18px 24px;
    background: linear-gradient(135deg, rgba(0, 212, 255, 0.06), rgba(0, 255, 213, 0.03));
    border-top: 1px solid rgba(0, 212, 255, 0.18);
    border-bottom: 1px solid rgba(0, 212, 255, 0.18);
    border-radius: 14px;
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 8px 14px;
    font-size: 0.85rem;
    backdrop-filter: blur(8px);
}

.friend-links-title {
    color: #00ffd5;
    font-weight: 700;
    margin-right: 6px;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.friend-links a {
    color: #cbd5e1;
    text-decoration: none;
    padding: 4px 10px;
    border-radius: 6px;
    border: 1px solid transparent;
    transition: all 0.3s;
    position: relative;
}

.friend-links a::after {
    content: '↗';
    margin-left: 4px;
    font-size: 0.7rem;
    opacity: 0.5;
    transition: opacity 0.3s;
}

.friend-links a:hover {
    color: #fff;
    background: linear-gradient(135deg, rgba(0, 255, 213, 0.18), rgba(0, 212, 255, 0.12));
    border-color: rgba(0, 255, 213, 0.35);
    transform: translateY(-1px);
    box-shadow: 0 4px 14px rgba(0, 255, 213, 0.2);
}

.friend-links a:hover::after {
    opacity: 1;
}

@media (max-width: 768px) {
    .friend-links {
        margin: 30px 16px 0;
        padding: 14px 16px;
        gap: 6px 10px;
    }
    .friend-links-title { font-size: 0.85rem; }
    .friend-links a { font-size: 0.78rem; padding: 3px 8px; }
}

/* ========== 响应式 ========== */
@media (max-width: 768px) {
    .nav-menu { display: none; }
    .hamburger { display: flex; }
    .section-title { font-size: 2rem; }
    .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 480px) {
    .section-title { font-size: 1.6rem; }
    .footer-grid { grid-template-columns: 1fr; }
}