/* ==============================
   项目13：首页样式
   黑色背景 + 大文字介绍
   ============================== */

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

/* 页面主体 */
body {
    margin: 0;
    padding: 0;
    background: #000;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    font-family: 'Helvetica Neue', Arial, 'Microsoft YaHei', sans-serif;
    overflow: hidden; /* 防止滚动 */
}

/* 容器 */
.container {
    text-align: center;
    color: #fff;
    animation: fadeIn 1.5s ease-in;
}

/* 主标题 */
.title {
    font-size: 72px;
    font-weight: 700;
    margin-bottom: 20px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: 4px;
}

/* 副标题 */
.subtitle {
    font-size: 28px;
    font-weight: 300;
    color: #888;
    margin-bottom: 40px;
    letter-spacing: 8px;
    text-transform: uppercase;
}

/* 描述文字 */
.description {
    font-size: 18px;
    color: #666;
    margin-bottom: 60px;
    line-height: 1.6;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* 进入按钮 */
.enter-btn {
    font-size: 24px;
    font-weight: 600;
    color: #fff;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border: none;
    padding: 18px 50px;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 10px 30px rgba(102, 126, 234, 0.4);
    display: inline-flex;
    align-items: center;
    gap: 10px;
}

/* 按钮悬停效果 */
.enter-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 40px rgba(102, 126, 234, 0.6);
}

.enter-btn:active {
    transform: translateY(0);
}

/* 箭头动画 */
.arrow {
    font-size: 28px;
    transition: transform 0.3s ease;
    display: inline-block;
}

.enter-btn:hover .arrow {
    transform: translateX(8px);
}

/* 淡入动画 */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ==============================
   响应式设计
   ============================== */

/* 平板横屏 (≤ 1199px) */
@media (max-width: 1199px) {
    .title {
        font-size: 56px;
    }

    .subtitle {
        font-size: 22px;
    }

    .description {
        font-size: 16px;
        margin-bottom: 50px;
    }

    .enter-btn {
        font-size: 20px;
        padding: 15px 40px;
    }
}

/* 平板竖屏 (≤ 768px) */
@media (max-width: 768px) {
    .title {
        font-size: 42px;
        letter-spacing: 2px;
    }

    .subtitle {
        font-size: 18px;
        letter-spacing: 4px;
    }

    .description {
        font-size: 14px;
        margin-bottom: 40px;
    }

    .enter-btn {
        font-size: 18px;
        padding: 12px 35px;
    }
}

/* 手机屏幕 (≤ 576px) */
@media (max-width: 576px) {
    .title {
        font-size: 32px;
        letter-spacing: 1px;
    }

    .subtitle {
        font-size: 16px;
        letter-spacing: 3px;
        margin-bottom: 30px;
    }

    .description {
        font-size: 13px;
        margin-bottom: 30px;
        padding: 0 20px;
    }

    .enter-btn {
        font-size: 16px;
        padding: 12px 30px;
    }

    .arrow {
        font-size: 24px;
    }
}