/* 
 * 学海智联 - 主CSS文件
 * 包含全局样式定义和共享组件样式
 */

/* ===== 变量定义 ===== */
:root {
    --primary-color: #4285f4;
    --primary-dark: #3367d6;
    --secondary-color: #34a853;
    --secondary-dark: #2d8d47;
    --accent-color: #ea4335;
    --accent-dark: #d62516;
    --dark-color: #202124;
    --light-color: #f8f9fa;
    --gray-color: #70757a;
    --gray-light: #e8eaed;
    --box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    --box-shadow-hover: 0 8px 25px rgba(0, 0, 0, 0.15);
    --transition: all 0.3s ease;
    --border-radius: 10px;
    --border-radius-lg: 15px;
    --border-radius-sm: 5px;
}

/* ===== 基础样式重置 ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px; /* 导航栏高度 */
}

body {
    font-family: 'PingFang SC', 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--dark-color);
    background-color: var(--light-color);
    display: block !important;
    font-size: 16px;
    overflow-x: hidden;
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

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

a:hover {
    color: var(--primary-dark);
}

h1, h2, h3, h4, h5, h6 {
    line-height: 1.3;
    margin-bottom: 20px;
    font-weight: 700;
    color: var(--dark-color);
}

p {
    margin-bottom: 20px;
}

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

section {
    padding: 100px 0;
    position: relative;
}

/* ===== 全局UI组件 ===== */

/* 按钮 */
.btn {
    display: inline-block;
    padding: 12px 25px;
    border-radius: 30px;
    font-weight: 500;
    text-align: center;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
    z-index: 1;
    cursor: pointer;
    font-size: 1rem;
    letter-spacing: 0.5px;
}

.btn::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: width 0.5s, height 0.5s;
    z-index: -1;
}

.btn:hover::after {
    width: 300px;
    height: 300px;
}

.btn.primary {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: white;
    box-shadow: 0 4px 15px rgba(66, 133, 244, 0.4);
    border: none;
}

.btn.primary:hover {
    box-shadow: 0 6px 20px rgba(66, 133, 244, 0.6);
    transform: translateY(-2px);
}

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

.btn.secondary:hover {
    background-color: var(--primary-color);
    color: white;
    transform: translateY(-2px);
}

.btn.accent {
    background: linear-gradient(135deg, var(--accent-color) 0%, var(--accent-dark) 100%);
    color: white;
    box-shadow: 0 4px 15px rgba(234, 67, 53, 0.4);
    border: none;
}

.btn.accent:hover {
    box-shadow: 0 6px 20px rgba(234, 67, 53, 0.6);
    transform: translateY(-2px);
}

/* 表单元素 */
input, textarea, select {
    width: 100%;
    padding: 12px 15px;
    border: 1px solid var(--gray-light);
    border-radius: var(--border-radius-sm);
    font-family: inherit;
    font-size: 1rem;
    color: var(--dark-color);
    background-color: white;
    transition: var(--transition);
}

input:focus, textarea:focus, select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(66, 133, 244, 0.1);
}

/* 标签 */
.tag {
    display: inline-block;
    padding: 5px 12px;
    font-size: 0.8rem;
    border-radius: 20px;
    margin-right: 8px;
    margin-bottom: 8px;
    background-color: rgba(66, 133, 244, 0.1);
    color: var(--primary-color);
    font-weight: 500;
}

/* 卡片 */
.card {
    background-color: white;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--box-shadow);
    transition: var(--transition);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--box-shadow-hover);
}

.card-body {
    padding: 25px;
}

.card-title {
    font-size: 1.3rem;
    margin-bottom: 15px;
}

/* 分隔线 */
.divider {
    width: 100%;
    height: 1px;
    background-color: var(--gray-light);
    margin: 30px 0;
}

/* 加载器 */
.loader {
    border: 3px solid rgba(66, 133, 244, 0.1);
    border-top: 3px solid var(--primary-color);
    border-radius: 50%;
    width: 30px;
    height: 30px;
    animation: spin 1s linear infinite;
    margin: 0 auto;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* 页面预加载动画 */
.preloader {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: var(--light-color);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 9999;
    transition: opacity 0.5s ease, visibility 0.5s ease;
}

.preloader.hidden {
    opacity: 0;
    visibility: hidden;
}

.preloader-content {
    text-align: center;
}

.preloader-spinner {
    border: 4px solid rgba(66, 133, 244, 0.1);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    width: 50px;
    height: 50px;
    animation: spin 1s linear infinite;
    margin: 0 auto 20px;
}

.preloader-text {
    font-size: 1.2rem;
    color: var(--primary-color);
    font-weight: 500;
}

/* 滚动到顶部按钮 */
.scroll-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 45px;
    height: 45px;
    background-color: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    z-index: 99;
    opacity: 0;
    visibility: hidden;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

.scroll-top.visible {
    opacity: 1;
    visibility: visible;
}

.scroll-top:hover {
    background-color: var(--primary-dark);
    transform: translateY(-5px);
}

/* 主题切换 */
.theme-toggle {
    width: 40px;
    height: 40px;
    background-color: var(--light-color);
    color: var(--dark-color);
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    transition: var(--transition);
    border: 1px solid var(--gray-light);
}

.theme-toggle:hover {
    background-color: var(--gray-light);
}

/* 深色模式 */
body.dark-mode {
    background-color: #121212;
    color: #e8eaed;
}

body.dark-mode h1, 
body.dark-mode h2, 
body.dark-mode h3, 
body.dark-mode h4, 
body.dark-mode h5, 
body.dark-mode h6 {
    color: #ffffff;
}

body.dark-mode p {
    color: #bdc1c6;
}

body.dark-mode .btn.secondary {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

body.dark-mode .tag {
    background-color: rgba(66, 133, 244, 0.2);
}

body.dark-mode .card {
    background-color: #1e1e1e;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

body.dark-mode .divider {
    background-color: #303134;
}

body.dark-mode .theme-toggle {
    background-color: #252525;
    color: #e8eaed;
    border-color: #303134;
}

body.dark-mode input, 
body.dark-mode textarea, 
body.dark-mode select {
    background-color: #1e1e1e;
    border-color: #303134;
    color: #e8eaed;
}

body.dark-mode input:focus, 
body.dark-mode textarea:focus, 
body.dark-mode select:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(66, 133, 244, 0.1);
}

/* 无障碍优化 */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    margin: -1px;
    padding: 0;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    border: 0;
}

/* 动画 */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideInUp {
    from {
        transform: translateY(30px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

/* 响应式调整 */
@media (max-width: 1200px) {
    body {
        font-size: 15px;
    }

    .container {
        width: 95%;
    }

    section {
        padding: 80px 0;
    }
}

@media (max-width: 992px) {
    body {
        font-size: 14px;
    }

    section {
        padding: 70px 0;
    }

    .btn {
        padding: 10px 20px;
    }
}

@media (max-width: 768px) {
    section {
        padding: 60px 0;
    }

    .btn {
        padding: 10px 18px;
        font-size: 0.95rem;
    }

    .scroll-top {
        bottom: 20px;
        right: 20px;
        width: 40px;
        height: 40px;
    }
}

@media (max-width: 480px) {
    section {
        padding: 50px 0;
    }

    .container {
        width: 100%;
        padding: 0 15px;
    }

    .btn {
        padding: 8px 16px;
        font-size: 0.9rem;
    }
}

/* ===== 通用组件样式 ===== */
.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-header h2 {
    font-size: 2.5rem;
    margin-bottom: 20px;
    position: relative;
    display: inline-block;
}

.underline {
    position: relative;
    display: inline-block;
}

.underline::after {
    content: '';
    position: absolute;
    width: 60%;
    height: 4px;
    background-color: var(--accent-color);
    bottom: -10px;
    left: 20%;
}

/* 页眉页脚加载失败时的应急样式 */
.header-footer-error {
    padding-top: 30px;
}

.header-footer-error section:first-child {
    margin-top: 60px;
}

/* 加载状态和错误处理样式 */
.loading-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 200px;
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 4px solid rgba(0, 0, 0, 0.1);
    border-left-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

.error-container {
    text-align: center;
    padding: 30px;
    margin: 20px 0;
    background-color: #fff3f3;
    border-left: 4px solid #ff3e3e;
}

.error-container h3 {
    color: #ff3e3e;
    margin-bottom: 10px;
}

/* 英雄区域标题样式 */
.animated-heading {
    font-size: 2.5rem;
    line-height: 1.3;
    margin-bottom: 1.5rem;
    font-weight: 700;
    color: var(--dark-color);
    display: block;
}

.gradient-text {
    background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-weight: 700;
}