/* ===================================
   XWChat - 现代化样式文件
   =================================== */

/* CSS 变量 */
:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --primary-light: #e0e7ff;
    --secondary-color: #8b5cf6;
    --success-color: #10b981;
    --error-color: #ef4444;
    --warning-color: #f59e0b;
    
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-muted: #9ca3af;
    
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-tertiary: #f3f4f6;
    
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    
    --gradient-primary: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #a855f7 100%);
    --gradient-hero: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    
    --transition-fast: 0.15s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;
}

/* 基础重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Microsoft YaHei', 'PingFang SC', 'Hiragino Sans GB', sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    overflow-x: hidden;
}

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

ul {
    list-style: none;
}

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

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    outline: none;
    transition: all var(--transition-base);
}

input {
    font-family: inherit;
    border: none;
    outline: none;
}

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

/* ===================================
   导航栏
   =================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    transition: all var(--transition-base);
}

.navbar.scrolled {
    box-shadow: var(--shadow-md);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 24px;
    font-weight: 700;
    color: var(--text-primary);
}

.logo-icon {
    font-size: 28px;
}

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

.nav-links {
    display: flex;
    align-items: center;
    gap: 32px;
}

.nav-links a {
    font-size: 15px;
    font-weight: 500;
    color: var(--text-secondary);
    position: relative;
    padding: 8px 0;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--primary-color);
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-primary);
    transition: width var(--transition-base);
}

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

.nav-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: 8px;
    background: transparent;
}

.mobile-menu-btn span {
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    transition: all var(--transition-base);
}

/* ===================================
   按钮样式
   =================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 20px;
    font-size: 15px;
    font-weight: 500;
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
    cursor: pointer;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: 0 4px 14px rgba(99, 102, 241, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.5);
}

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

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

.btn-ghost {
    background: transparent;
    color: var(--text-secondary);
}

.btn-ghost:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.btn-lg {
    padding: 14px 32px;
    font-size: 16px;
}

.btn-block {
    width: 100%;
}

/* ===================================
   Hero 区域
   =================================== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 70px;
    overflow: hidden;
    background: linear-gradient(180deg, #f9fafb 0%, #ffffff 100%);
}

.hero-bg {
    position: absolute;
    inset: 0;
    overflow: hidden;
}

.gradient-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.5;
    animation: float 20s ease-in-out infinite;
}

.orb-1 {
    width: 400px;
    height: 400px;
    background: var(--primary-color);
    top: -100px;
    right: -100px;
    animation-delay: 0s;
}

.orb-2 {
    width: 300px;
    height: 300px;
    background: var(--secondary-color);
    bottom: 10%;
    left: -50px;
    animation-delay: -7s;
}

.orb-3 {
    width: 250px;
    height: 250px;
    background: #a855f7;
    bottom: -50px;
    right: 20%;
    animation-delay: -14s;
}

@keyframes float {
    0%, 100% {
        transform: translate(0, 0) scale(1);
    }
    33% {
        transform: translate(30px, -50px) scale(1.1);
    }
    66% {
        transform: translate(-20px, 30px) scale(0.9);
    }
}

.hero-content {
    position: relative;
    z-index: 1;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.hero-title {
    font-size: 56px;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 24px;
    color: var(--text-primary);
}

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

.hero-subtitle {
    font-size: 18px;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 32px;
}

.hero-actions {
    display: flex;
    gap: 16px;
    margin-bottom: 48px;
}

.hero-stats {
    display: flex;
    gap: 40px;
}

.stat-item {
    display: flex;
    flex-direction: column;
}

.stat-number {
    font-size: 32px;
    font-weight: 700;
    color: var(--primary-color);
}

.stat-label {
    font-size: 14px;
    color: var(--text-muted);
    margin-top: 4px;
}

/* 聊天预览 */
.hero-image {
    display: flex;
    justify-content: center;
    align-items: center;
}

.chat-preview {
    width: 380px;
    background: white;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    overflow: hidden;
    border: 1px solid var(--border-color);
}

.chat-header {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px 20px;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
}

.chat-avatar {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--gradient-primary);
}

.chat-info {
    display: flex;
    flex-direction: column;
}

.chat-name {
    font-weight: 600;
    color: var(--text-primary);
}

.chat-status {
    font-size: 13px;
    color: var(--success-color);
}

.chat-messages {
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 16px;
    min-height: 280px;
}

.message {
    display: flex;
    flex-direction: column;
    max-width: 80%;
}

.message.received {
    align-self: flex-start;
}

.message.sent {
    align-self: flex-end;
    align-items: flex-end;
}

.message-bubble {
    padding: 12px 16px;
    border-radius: var(--radius-lg);
    font-size: 14px;
    line-height: 1.5;
}

.message.received .message-bubble {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border-bottom-left-radius: 4px;
}

.message.sent .message-bubble {
    background: var(--gradient-primary);
    color: white;
    border-bottom-right-radius: 4px;
}

.message-time {
    font-size: 12px;
    color: var(--text-muted);
    margin-top: 4px;
}

/* ===================================
   功能特性
   =================================== */
.features {
    padding: 100px 0;
    background: var(--bg-secondary);
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-title {
    font-size: 40px;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 12px;
}

.section-subtitle {
    font-size: 18px;
    color: var(--text-secondary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.feature-card {
    background: white;
    padding: 32px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
    text-align: center;
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.feature-icon {
    font-size: 48px;
    margin-bottom: 20px;
}

.feature-card h3 {
    font-size: 20px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 12px;
}

.feature-card p {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.7;
}

/* ===================================
   下载引导
   =================================== */
.download-cta {
    padding: 100px 0;
    background: var(--gradient-primary);
}

.download-content {
    text-align: center;
    color: white;
}

.download-content h2 {
    font-size: 40px;
    font-weight: 700;
    margin-bottom: 16px;
}

.download-content p {
    font-size: 18px;
    opacity: 0.9;
    margin-bottom: 32px;
}

.download-cta .btn-primary {
    background: white;
    color: var(--primary-color);
    box-shadow: 0 4px 14px rgba(0, 0, 0, 0.2);
}

.download-cta .btn-primary:hover {
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
}

/* ===================================
   页脚
   =================================== */
.footer {
    background: var(--text-primary);
    color: white;
    padding: 60px 0 30px;
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 60px;
    margin-bottom: 40px;
}

.footer-brand .logo {
    margin-bottom: 16px;
}

.footer-brand .logo-text {
    -webkit-text-fill-color: white;
}

.footer-brand p {
    color: var(--text-muted);
    font-size: 15px;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 40px;
}

.footer-column h4 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 20px;
}

.footer-column ul {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.footer-column a {
    color: var(--text-muted);
    font-size: 15px;
}

.footer-column a:hover {
    color: white;
}

.footer-bottom {
    padding-top: 30px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    text-align: center;
}

.footer-bottom p {
    color: var(--text-muted);
    font-size: 14px;
}

/* ===================================
   模态框
   =================================== */
.modal {
    display: none;
    position: fixed;
    inset: 0;
    z-index: 2000;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: white;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    max-width: 420px;
    width: 100%;
    position: relative;
    animation: modalSlideIn 0.3s ease;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.modal-close {
    position: absolute;
    top: 16px;
    right: 16px;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    font-size: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.modal-close:hover {
    background: var(--error-color);
    color: white;
}

.auth-modal {
    padding: 40px;
}

.auth-header {
    text-align: center;
    margin-bottom: 32px;
}

.auth-header h2 {
    font-size: 28px;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.auth-header p {
    color: var(--text-secondary);
    font-size: 15px;
}

.auth-form {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.form-group label {
    font-size: 14px;
    font-weight: 500;
    color: var(--text-primary);
}

.form-group input {
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 15px;
    transition: all var(--transition-fast);
}

.form-group input:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px var(--primary-light);
}

.form-group input::placeholder {
    color: var(--text-muted);
}

.form-options {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
    color: var(--text-secondary);
    cursor: pointer;
}

.checkbox-label input {
    width: 16px;
    height: 16px;
    cursor: pointer;
}

.forgot-link {
    font-size: 14px;
    color: var(--primary-color);
}

.forgot-link:hover {
    text-decoration: underline;
}

.auth-footer {
    text-align: center;
    margin-top: 24px;
    padding-top: 24px;
    border-top: 1px solid var(--border-color);
}

.auth-footer p {
    font-size: 15px;
    color: var(--text-secondary);
}

.auth-footer a {
    color: var(--primary-color);
    font-weight: 500;
}

.auth-footer a:hover {
    text-decoration: underline;
}

/* ===================================
   Toast 提示
   =================================== */
.toast {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    z-index: 3000;
    padding: 14px 28px;
    border-radius: var(--radius-md);
    font-size: 15px;
    font-weight: 500;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    transition: all var(--transition-base);
}

.toast.show {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

.toast.success {
    background: var(--success-color);
    color: white;
}

.toast.error {
    background: var(--error-color);
    color: white;
}

.toast.info {
    background: var(--primary-color);
    color: white;
}

/* ===================================
   响应式设计
   =================================== */
@media (max-width: 968px) {
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero-title {
        font-size: 42px;
    }
    
    .hero-actions {
        justify-content: center;
    }
    
    .hero-stats {
        justify-content: center;
    }
    
    .hero-image {
        order: -1;
    }
    
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .footer-content {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 640px) {
    .nav-links,
    .nav-actions {
        display: none;
    }
    
    .mobile-menu-btn {
        display: flex;
    }
    
    .hero-title {
        font-size: 32px;
    }
    
    .hero-subtitle {
        font-size: 16px;
    }
    
    .hero-actions {
        flex-direction: column;
    }
    
    .hero-stats {
        flex-direction: column;
        gap: 20px;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .section-title {
        font-size: 32px;
    }
    
    .chat-preview {
        width: 100%;
        max-width: 340px;
    }
}