/**
 * 洁博利 · 发展历程页面完整样式（动效强化版）
 * @version 3.0.0
 * @update 2026-05-23
 * @description 全屏背景 + GSAP ScrollTrigger 滚动驱动时间轴
 * 保留所有品牌色、导航、CTA、浮动按钮等公共样式
 */

/* ========== 全局变量与重置 ========== */
:root {
    --color-primary: #1b9b97;
    --color-primary-dark: #0f7e7a;
    --color-secondary: #5a6b7a;
    --color-dark: #1e2a2e;
    --color-soft-dark: #2c3e40;
    --color-gold: #c6a05b;
    --color-gold-light: #e9d6b0;
    --color-white: #ffffff;
    --color-bg: #fbfcfd;
    --color-card-bg: #ffffff;
    --color-border: #eef2f2;
    --shadow-sm: 0 8px 20px rgba(0, 0, 0, 0.02), 0 2px 6px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 20px 35px -12px rgba(0, 0, 0, 0.08);
    --shadow-hover: 0 24px 42px -16px rgba(0, 0, 0, 0.12);
    --transition-smooth: all 0.4s cubic-bezier(0.2, 0.9, 0.4, 1.1);
    --border-radius-card: 2rem;
    --border-radius-md: 1.5rem;
    --border-radius-sm: 1rem;
    --font-body: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, sans-serif;
}

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

body {
    background-color: #1e2a2e; /* 深色底避免背景图加载时白屏 */
    font-family: var(--font-body);
    color: var(--color-dark);
    line-height: 1.5;
    scroll-behavior: smooth;
}

.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 32px;
}

a {
    text-decoration: none;
    transition: var(--transition-smooth);
}

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

/* ========== 导航菜单 ========== */
.join-nav-menu {
    background: var(--color-soft-dark) !important;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    gap: 2.5rem;
    padding: 1rem 1.5rem;
    margin: 0;
    list-style: none;
    position: relative;
    z-index: 100;
}

.join-nav-link {
    color: rgba(255, 255, 255, 0.85) !important;
    font-weight: 500;
    font-size: 1rem;
    letter-spacing: 0.5px;
    padding: 0.4rem 0;
    position: relative;
    background: transparent !important;
    border: none !important;
    box-shadow: none !important;
    transition: color 0.2s ease;
}

.join-nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-gold);
    transition: width 0.25s ease-out;
}

.join-nav-link:hover::after,
.join-nav-link.active::after {
    width: 100%;
}

.join-nav-link:hover,
.join-nav-link.active {
    color: var(--color-white) !important;
}

/* ========== 底部CTA ========== */
.footer-cta {
    background: linear-gradient(135deg, #1e2a2e, #142022);
    text-align: center;
    padding: 4rem 2rem;
    color: white;
    border-radius: 2rem 2rem 0 0;
    margin-top: 2rem;
}

.footer-cta h3 {
    font-size: 1.8rem;
    margin-bottom: 0.75rem;
}

.footer-cta p {
    margin-bottom: 1.5rem;
    opacity: 0.8;
}

.btn-primary {
    display: inline-block;
    background: var(--color-gold);
    color: #fff;
    padding: 0.8rem 2rem;
    border-radius: 60px;
    font-weight: 600;
    transition: var(--transition-smooth);
}

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

/* ========== 悬浮按钮 ========== */
.float-buttons {
    position: fixed;
    right: 24px;
    bottom: 80px;
    display: flex;
    flex-direction: column;
    gap: 14px;
    z-index: 999;
}

.float-btn {
    width: 52px;
    height: 52px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-gold);
    color: white;
    box-shadow: var(--shadow-md);
    transition: var(--transition-smooth);
}

.float-btn:hover {
    transform: scale(1.05);
    background: var(--color-primary);
}

/* ========== 背景图容器 ========== */
.history-bg-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    z-index: 0;
    overflow: hidden;
}

.history-bg-layer {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    opacity: 0;
    will-change: transform, opacity;
    transform: scale(1);
}

.history-bg-layer.active {
    opacity: 1;
}

.history-bg-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.55);
    z-index: 1;
}

/* ========== 时间轴内容区 ========== */
.timeline-section {
    position: relative;
    z-index: 10;
    padding: 5rem 0 8rem;
    pointer-events: none;
}

.timeline-section .container,
.timeline-section .timeline-wrapper,
.timeline-section .timeline-item,
.timeline-section .timeline-card,
.timeline-section .timeline-card a {
    pointer-events: auto;
}

.timeline-header {
    text-align: center;
    margin-bottom: 4rem;
}

.timeline-header h1 {
    font-size: 3rem;
    font-weight: 700;
    color: #fff;
    margin-bottom: 0.75rem;
    letter-spacing: -0.02em;
    text-shadow: 0 2px 16px rgba(0,0,0,0.4);
}

.timeline-header p {
    font-size: 1.15rem;
    color: rgba(255,255,255,0.85);
    text-shadow: 0 1px 8px rgba(0,0,0,0.3);
}

.timeline-wrapper {
    position: relative;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 32px;
}

/* 中间竖线 */
.timeline-line {
    position: absolute;
    left: 50%;
    top: 0;
    bottom: 0;
    width: 3px;
    background: linear-gradient(180deg, rgba(27,155,151,0.8), rgba(198,160,91,0.8), rgba(27,155,151,0.8));
    transform: translateX(-50%);
    border-radius: 4px;
    z-index: 1;
    transform-origin: top center;
    will-change: transform;
}

/* 时间轴节点 */
.timeline-item {
    position: relative;
    display: flex;
    align-items: flex-start;
    margin-bottom: 4rem;
    opacity: 0;
    transform: translateY(50px);
    will-change: transform, opacity;
    z-index: 2;
}

.timeline-item:nth-child(odd) {
    flex-direction: row;
    padding-right: calc(50% + 52px);
}

.timeline-item:nth-child(even) {
    flex-direction: row-reverse;
    padding-left: calc(50% + 52px);
}

/* 年份节点圆点 */
.timeline-dot {
    position: absolute;
    left: 50%;
    top: 32px;
    width: 56px;
    height: 56px;
    background: linear-gradient(135deg, #c6a05b, #e9d6b0);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #1e2a2e;
    font-weight: 800;
    font-size: 0.85rem;
    transform: translate(-50%, -50%) scale(0);
    z-index: 3;
    box-shadow: 0 0 24px rgba(198,160,91,0.5), 0 4px 12px rgba(0,0,0,0.2);
    will-change: transform;
}

/* 内容卡片 */
.timeline-card {
    background: rgba(255, 255, 255, 0.12);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: 1.5rem;
    padding: 1.8rem 2rem;
    border: 1px solid rgba(255,255,255,0.2);
    position: relative;
    flex: 1;
    will-change: transform, opacity;
}

.timeline-card ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.timeline-card li {
    font-size: 0.95rem;
    color: rgba(255,255,255,0.88);
    line-height: 1.7;
    margin-bottom: 0.5rem;
    padding-left: 1.2rem;
    position: relative;
}

.timeline-card li::before {
    content: "";
    position: absolute;
    left: 0;
    top: 0.55rem;
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: rgba(198,160,91,0.8);
}

.timeline-card li a {
    color: #e9d6b0;
    text-decoration: underline;
    text-underline-offset: 2px;
}

.timeline-card h3 {
    font-size: 1.35rem;
    font-weight: 700;
    color: #fff;
    margin-bottom: 0.75rem;
    line-height: 1.3;
    text-shadow: 0 1px 4px rgba(0,0,0,0.3);
}

.timeline-card h3 b {
    color: #e9d6b0;
}

/* 卡片侧边金色装饰条 */
.timeline-card::before {
    content: '';
    position: absolute;
    top: 1.5rem;
    bottom: 1.5rem;
    width: 3px;
    background: rgba(198,160,91,0.7);
    border-radius: 2px;
}

.timeline-item:nth-child(odd) .timeline-card::before {
    right: 0;
}

.timeline-item:nth-child(even) .timeline-card::before {
    left: 0;
}

/* ========== 响应式 ========== */
@media (max-width: 768px) {
    .join-nav-menu {
        gap: 1.2rem;
        padding: 0.8rem;
    }
    .join-nav-link {
        font-size: 0.85rem;
    }
    .container {
        padding: 0 20px;
    }
    .footer-cta {
        padding: 3rem 1.5rem;
    }
    .timeline-line {
        left: 32px;
    }
    .timeline-item,
    .timeline-item:nth-child(odd),
    .timeline-item:nth-child(even) {
        flex-direction: row;
        padding-left: 64px;
        padding-right: 0;
    }
    .timeline-dot {
        left: 32px;
        width: 40px;
        height: 40px;
        font-size: 0.7rem;
    }
    .timeline-card {
        padding: 1.2rem 1.2rem;
    }
    .timeline-card h3 {
        font-size: 1.1rem;
    }
    .timeline-card li {
        font-size: 0.85rem;
    }
    .timeline-card::before {
        left: 0;
    }
    .timeline-item:nth-child(odd) .timeline-card::before {
        left: 0;
        right: auto;
    }
    .timeline-header h1 {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    .timeline-dot {
        width: 32px;
        height: 32px;
        font-size: 0.65rem;
    }
    .timeline-card {
        padding: 1rem;
    }
}