/* 青少年人工智能学习平台样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --secondary-color: #ec4899;
    --accent-color: #10b981;
    --background-color: #f8fafc;
    --surface-color: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    --gradient-primary: linear-gradient(135deg, #6366f1 0%, #ec4899 100%);
    --gradient-secondary: linear-gradient(135deg, #10b981 0%, #06b6d4 100%);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--background-color);
    color: var(--text-primary);
    line-height: 1.6;
}

/* 容器 */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* 按钮样式 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 0.75rem;
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 0.875rem;
    min-height: 44px;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: var(--shadow);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: var(--surface-color);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background: var(--background-color);
    transform: translateY(-1px);
}

.btn-full {
    width: 100%;
}

/* 表单样式 */
.form-group {
    margin-bottom: 1.5rem;
}

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

.form-input {
    width: 100%;
    padding: 0.875rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    font-size: 1rem;
    transition: all 0.3s ease;
    background: var(--surface-color);
}

.form-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.form-select {
    width: 100%;
    padding: 0.875rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    font-size: 1rem;
    background: var(--surface-color);
    cursor: pointer;
}

/* 卡片样式 */
.card {
    background: var(--surface-color);
    border-radius: 1rem;
    padding: 2rem;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.card-header {
    text-align: center;
    margin-bottom: 2rem;
}

.card-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.card-subtitle {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* 导航栏 */
.navbar {
    background: var(--surface-color);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(8px);
}

.navbar-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 1rem;
}

.navbar-brand {
    font-size: 1.5rem;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-decoration: none;
    flex-shrink: 0;
    display: flex;
    align-items: center;
}

.navbar-brand i {
    color: var(--primary-color);
}

.navbar-nav {
    display: flex;
    list-style: none;
    gap: 1.5rem;
    align-items: center;
    flex-wrap: wrap;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    white-space: nowrap;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.nav-link:hover {
    color: var(--primary-color);
    background: rgba(99, 102, 241, 0.1);
    transform: translateY(-1px);
}

.nav-link.active {
    color: var(--primary-color);
    background: rgba(99, 102, 241, 0.15);
    font-weight: 600;
}

.nav-link i {
    font-size: 0.875rem;
    flex-shrink: 0;
}

.gold-beans-display {
    display: flex;
    align-items: center;
    padding: 0.5rem 1rem;
    background: rgba(99, 102, 241, 0.1);
    border-radius: 0.5rem;
    white-space: nowrap;
    font-size: 0.875rem;
}

.gold-beans-display i {
    color: #f59e0b;
    margin-right: 0.5rem;
}

.gold-beans-display .amount {
    color: var(--primary-color);
    font-weight: 600;
}

.gold-beans-display .label {
    color: var(--text-secondary);
    margin-left: 0.25rem;
}

/* 认证页面样式 */
.auth-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    padding: 2rem 1rem;
}

.auth-card {
    width: 100%;
    max-width: 400px;
    background: var(--surface-color);
    border-radius: 1.5rem;
    padding: 2.5rem;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
}

.auth-header {
    text-align: center;
    margin-bottom: 2rem;
}

.auth-logo {
    width: 80px;
    height: 80px;
    background: var(--gradient-primary);
    border-radius: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1rem;
    font-size: 2rem;
    color: white;
}

.auth-title {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.auth-subtitle {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .navbar-container {
        flex-direction: column;
        align-items: stretch;
        gap: 1rem;
    }
    
    .navbar-brand {
        text-align: center;
        font-size: 1.25rem;
        justify-content: center;
    }
    
    .navbar-nav {
        justify-content: center;
        gap: 0.75rem;
        flex-wrap: wrap;
    }
    
    .nav-link {
        padding: 0.75rem 1rem;
        font-size: 0.875rem;
        flex: 1;
        text-align: center;
        min-width: auto;
        justify-content: center;
        gap: 0.375rem;
    }
    
    .nav-link i {
        font-size: 0.8rem;
    }
    
    .gold-beans-display {
        justify-content: center;
        padding: 0.75rem 1rem;
        font-size: 1rem;
        font-weight: 600;
    }
    
    .auth-card {
        padding: 2rem;
        margin: 1rem;
    }
    
    .container {
        padding: 0 0.5rem;
    }
}

@media (max-width: 480px) {
    .navbar {
        padding: 0.75rem 0;
    }
    
    .navbar-brand {
        font-size: 1.125rem;
    }
    
    .navbar-nav {
        gap: 0.5rem;
        grid-template-columns: repeat(3, 1fr);
        display: grid;
        width: 100%;
    }
    
    .nav-link {
        padding: 0.75rem 0.5rem;
        font-size: 0.8rem;
        text-align: center;
        justify-content: center;
        gap: 0.25rem;
        flex-direction: column;
        min-height: 60px;
    }
    
    .nav-link i {
        font-size: 1rem;
        margin-bottom: 0.25rem;
    }
    
    .gold-beans-display {
        padding: 0.5rem 0.75rem;
        font-size: 0.875rem;
        grid-column: span 3;
        margin-top: 0.5rem;
    }
    
    .container {
        padding: 0 0.5rem;
    }
    
    /* 移动端特定的卡片优化 */
    .card {
        padding: 1.5rem;
        margin: 0.5rem 0;
    }
    
    /* 移动端表单优化 */
    .form-input, .form-select {
        font-size: 16px; /* 防止iOS缩放 */
    }
    
    /* 移动端分类网格优化 */
    .categories-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .category-card {
        padding: 1.5rem;
    }
    
    .category-icon {
        width: 60px;
        height: 60px;
        font-size: 1.5rem;
    }
    
    .category-title {
        font-size: 1.25rem;
    }
    
    /* 移动端英雄区优化 */
    .hero-section {
        padding: 3rem 0;
    }
    
    .hero-title {
        font-size: 1.75rem;
        line-height: 1.3;
    }
    
    .hero-subtitle {
        font-size: 0.9rem;
    }
}

/* 动画效果 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in-up {
    animation: fadeInUp 0.6s ease forwards;
}

/* 加载状态 */
.loading {
    position: relative;
    pointer-events: none;
}

.loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 20px;
    height: 20px;
    margin: -10px 0 0 -10px;
    border: 2px solid transparent;
    border-top-color: currentColor;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* 消息提示 */
.alert {
    padding: 1rem 1.25rem;
    border-radius: 0.75rem;
    margin-bottom: 1rem;
    border: 1px solid transparent;
}

.alert-success {
    background-color: rgba(16, 185, 129, 0.1);
    border-color: rgba(16, 185, 129, 0.2);
    color: #065f46;
}

.alert-error {
    background-color: rgba(239, 68, 68, 0.1);
    border-color: rgba(239, 68, 68, 0.2);
    color: #991b1b;
}

.alert-info {
    background-color: rgba(59, 130, 246, 0.1);
    border-color: rgba(59, 130, 246, 0.2);
    color: #1e3a8a;
}

/* 工具类 */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }
.mb-1 { margin-bottom: 0.25rem; }
.mb-2 { margin-bottom: 0.5rem; }
.mb-3 { margin-bottom: 1rem; }
.mb-4 { margin-bottom: 1.5rem; }
.mt-1 { margin-top: 0.25rem; }
.mt-2 { margin-top: 0.5rem; }
.mt-3 { margin-top: 1rem; }
.mt-4 { margin-top: 1.5rem; }
.hidden { display: none; }
.block { display: block; }
.inline-block { display: inline-block; }
.flex { display: flex; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.w-full { width: 100%; }
.h-full { height: 100%; }