#contact.contact-full-section {
    width: 100%;
    /* 1. 改为 min-height，让高度更有弹性 */
    min-height: 100vh;
    background-color: #fafafa;
    /* 确保背景色与 News 一致，防止颜色断层 */
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-start;

    /* 2. 移除可能导致高度溢出的负 margin 或绝对定位干扰 */
    margin: 0;
    position: relative;
    overflow: hidden;

    /* 3. 精确控制内边距：
       通过增加顶部内边距来平衡导航栏高度，同时确保不会看到上一个 Section */
    padding: 120px 5% 80px 5%;
    box-sizing: border-box;

    /* 4. 关键：解决“黑边”和滚动位置问题
       scroll-margin-top 应该匹配导航栏的实际高度 (约 80px-100px) */
    scroll-margin-top: 80px;
}

/* 移除旧有的背景装饰，保持图3的纯净感 */
#contact.contact-full-section::before,
#contact.contact-full-section::after {
    display: none;
}

.contact-container {
    width: 100%;
    max-width: 750px;
    margin: 0 auto;
    z-index: 10;
    /* 5. 确保内容不会被压缩 */
    flex-shrink: 0;
}

/* --- 标题样式 --- */
.form-header h2 {
    font-size: clamp(1.6em, 3.2vw, 3.2em);
    font-weight: 300;
    margin-bottom: 60px;
    color: #063f44;
    letter-spacing: -0.02em;
    text-align: left;
    /* 匹配图3风格 */
}

/* --- 表单元素容器 --- */
.form-item {
    margin-bottom: 35px;
    position: relative;
    display: flex;
    align-items: center;
    /* 垂直对齐图标和输入框 */
}

/* --- 图标基础样式 --- */
.input-icon {
    position: absolute;
    left: 0;
    bottom: 12px;
    /* 底部对齐下划线 */
    font-size: 1.2rem;
    color: #abb5be;
    /* 默认灰色，与 placeholder 一致 */
    transition: color 0.4s ease;
    pointer-events: none;
    /* 防止点击图标时无法聚焦输入框 */
}

/* 留言框的图标位置稍微上移，不要沉到底部 */
.form-item:has(textarea) .input-icon {
    top: 12px;
    bottom: auto;
}

/* --- 极简输入框 (下划线风格) --- */
.minimal-input {
    width: 100%;
    border: none !important;
    border-bottom: 1.5px solid #d0d0d0 !important;
    padding: 12px 0 12px 35px !important;
    /* 左侧留出 35px 空间 */
    font-size: 1.1rem !important;
    background: transparent !important;
    outline: none !important;
    border-radius: 0 !important;
    color: #1a2b3c;
    transition: all 0.3s ease;
}

/* --- 焦点状态下图标变色 --- */
.form-item:focus-within .input-icon {
    color: var(--p-green);
}

.minimal-input:focus {
    border-bottom-color: var(--p-green) !important;
}

/* 占位符颜色 */
.minimal-input::placeholder {
    color: #abb5be;
    font-weight: 400;
}

/* 留言框高度 */
textarea.minimal-input {
    min-height: 130px;
    resize: none;
}

/* --- 交互动效：下划线生长动画 --- */
.form-item::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--p-green);
    transition: width 0.5s cubic-bezier(0.22, 1, 0.36, 1);
}

.form-item:focus-within::after {
    width: 100%;
}

/* --- 提交按钮 (图3深色矩形) --- */
.form-action {
    margin-top: 20px;
    text-align: left;
    padding-bottom: 20px;
}

.btn-send-now {
    background-color: #24292e;
    color: #ffffff;
    border: none;
    padding: 18px 70px;
    font-weight: 300;
    font-size: 1.05rem;
    cursor: pointer;
    border-radius: 0;
    transition: all 0.3s ease;
    letter-spacing: 1px;
}

.btn-send-now:hover {
    background-color: #000;
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

/* ==========================================================================
   2K / 4K / 超宽屏适配 (解决方案 1 & 2)
   ========================================================================== */
@media screen and (min-width: 2000px) {
    #contact.contact-full-section {
        /* 调整布局位置：在 4K 屏下强制垂直居中，消除底部空位 */
        justify-content: center !important;
        padding-top: 0 !important;
        /* 居中时不再需要顶部 120px 偏移 */
    }

    .contact-container {
        /* 按比例缩放：增加容器最大宽度 */
        max-width: 1100px !important;
    }

    .form-header h2 {
        /* 按比例缩放：增大标题字号 */
        font-size: 5rem !important;
        margin-bottom: 80px;
    }

    .minimal-input {
        /* 按比例缩放：增大输入文字和内边距 */
        font-size: 1.5rem !important;
        padding: 20px 0 20px 50px !important;
    }

    .input-icon {
        /* 按比例缩放：增大图标 */
        font-size: 1.8rem !important;
        bottom: 20px !important;
    }

    .form-item:has(textarea) .input-icon {
        top: 20px !important;
    }

    .form-item {
        margin-bottom: 50px !important;
    }

    .btn-send-now {
        /* 按比例缩放：增大按钮尺寸 */
        padding: 25px 100px !important;
        font-size: 1.3rem !important;
    }
}

/* ==========================================================================
   入场动画 (配合 Intersection Observer JS 使用)
   ========================================================================== */

/* 初始隐藏状态 */
.contact-form-minimal .form-header,
.contact-form-minimal .form-item,
.contact-form-minimal .form-action {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s cubic-bezier(0.22, 1, 0.36, 1);
}

/* 激活状态：当给 .contact-full-section 添加 .is-visible 类时触发 */
.contact-full-section.is-visible .form-header,
.contact-full-section.is-visible .form-item,
.contact-full-section.is-visible .form-action {
    opacity: 1;
    transform: translateY(0);
}

/* 级联延迟：严格按照您初版的 transition-delay 逻辑 */
.is-visible .form-header {
    transition-delay: 0.1s;
}

.is-visible .form-item:nth-child(1) {
    transition-delay: 0.2s;
}

.is-visible .form-item:nth-child(2) {
    transition-delay: 0.3s;
}

.is-visible .form-item:nth-child(3) {
    transition-delay: 0.4s;
}

.is-visible .form-item:nth-child(4) {
    transition-delay: 0.5s;
}

.is-visible .form-item:nth-child(5) {
    transition-delay: 0.6s;
}

.is-visible .form-action {
    transition-delay: 0.7s;
}

/* ==========================================================================
   响应式适配 (手机端)
   ========================================================================== */
@media (max-width: 768px) {
    #contact.contact-full-section {
        min-height: auto;
        /* 手机端不需要强制全屏 */
        padding-top: 100px;
    }

    .form-header h2 {
        font-size: 2rem;
        margin-bottom: 40px;
    }

    .form-item {
        margin-bottom: 30px;
    }

    .btn-send-now {
        width: 100%;
        /* 手机端按钮撑满 */
    }
}