/* ===================================
   AI英语学习助手 - 现代化UI设计系统
   =================================== */

/* 设计主题：简洁优雅，功能至上
 * 配色方案：柔和紫蓝渐变 + 温暖辅助色
 * 设计原则：清晰的视觉层次、舒适的间距、流畅的交互
 */

/* CSS变量定义 - 统一的设计令牌 */
:root {
    /* 主色调 */
    --primary-gradient: linear-gradient(135deg, #7c3aed 0%, #6366f1 50%, #8b5cf6 100%);
    --primary-light: #a78bfa;
    --primary-dark: #6d28d9;
    --primary-bg: #f5f3ff;

    /* 辅助色 */
    --secondary-gradient: linear-gradient(135deg, #64748b 0%, #475569 100%);
    --success-gradient: linear-gradient(135deg, #10b981 0%, #059669 100%);
    --danger-gradient: linear-gradient(135deg, #ef4444 0%, #dc2626 100%);
    --warning-gradient: linear-gradient(135deg, #f59e0b 0%, #d97706 100%);
    --info-gradient: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%);

    /* 中性色 */
    --bg-gradient: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
    --card-bg: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --text-tertiary: #94a3b8;
    --border-color: #e2e8f0;
    --border-hover: #cbd5e1;

    /* 阴影 */
    --shadow-sm: 0 1px 2px 0 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);

    /* 间距 */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 12px;
    --spacing-lg: 16px;
    --spacing-xl: 20px;
    --spacing-2xl: 24px;
    --spacing-3xl: 32px;

    /* 圆角 */
    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --radius-full: 9999px;

    /* 动画 */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* 全局重置和基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica', 'Arial', sans-serif;
    background: var(--bg-gradient);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    padding: var(--spacing-xl);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

/* ===================================
   卡片组件
   =================================== */
.card {
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    padding: var(--spacing-3xl);
    margin-bottom: var(--spacing-xl);
    border: 1px solid var(--border-color);
    transition: all var(--transition-base);
}

.card:hover {
    box-shadow: var(--shadow-lg);
}

/* ===================================
   排版
   =================================== */
h1 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
    font-size: 32px;
    font-weight: 700;
    letter-spacing: -0.5px;
}

h2 {
    font-size: 24px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
}

h3 {
    font-size: 20px;
    font-weight: 600;
    color: var(--text-primary);
}

.subtitle {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    font-size: 15px;
    font-weight: 400;
}

/* ===================================
   按钮组件
   =================================== */
button {
    background: var(--primary-gradient);
    color: white;
    padding: var(--spacing-md) var(--spacing-xl);
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    font-size: 14px;
    font-weight: 600;
    transition: all var(--transition-base);
    box-shadow: var(--shadow-sm);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    letter-spacing: 0.025em;
}

button:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    filter: brightness(1.05);
}

button:active:not(:disabled) {
    transform: translateY(0);
    box-shadow: var(--shadow-sm);
}

button:focus {
    outline: none;
    box-shadow: 0 0 0 3px rgba(124, 58, 237, 0.2);
}

button:disabled {
    background: var(--border-color);
    color: var(--text-tertiary);
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

/* 按钮变体 */
button.btn-secondary {
    background: var(--secondary-gradient);
}

button.btn-danger {
    background: var(--danger-gradient);
}

button.btn-success {
    background: var(--success-gradient);
}

button.btn-small {
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: 13px;
}

/* ===================================
   表单组件
   =================================== */
.form-group {
    margin-bottom: var(--spacing-lg);
}

label {
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
    color: var(--text-primary);
    font-size: 14px;
}

input,
select,
textarea {
    width: 100%;
    padding: var(--spacing-md);
    border: 1.5px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 14px;
    transition: all var(--transition-base);
    background: #ffffff;
    color: var(--text-primary);
}

input:hover,
select:hover,
textarea:hover {
    border-color: var(--border-hover);
}

input:focus,
select:focus,
textarea:focus {
    outline: none;
    border-color: var(--primary-light);
    box-shadow: 0 0 0 3px rgba(124, 58, 237, 0.1);
}

input::placeholder,
textarea::placeholder {
    color: var(--text-tertiary);
}

/* ===================================
   进度条组件
   =================================== */
.progress-bar-container {
    margin: var(--spacing-lg) 0;
}

.progress {
    width: 100%;
    height: 28px;
    background-color: #f1f5f9;
    border-radius: var(--radius-full);
    overflow: hidden;
    box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.1);
}

.progress-bar {
    height: 100%;
    background: var(--primary-gradient);
    transition: width var(--transition-slow);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 600;
    font-size: 12px;
    letter-spacing: 0.5px;
    position: relative;
    overflow: hidden;
}

.progress-bar::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(
        90deg,
        transparent,
        rgba(255, 255, 255, 0.2),
        transparent
    );
    animation: shimmer 2s infinite;
}

@keyframes shimmer {
    0% {
        transform: translateX(-100%);
    }
    100% {
        transform: translateX(100%);
    }
}

/* ===================================
   状态徽章
   =================================== */
.status-badge {
    display: inline-flex;
    align-items: center;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-full);
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 0.025em;
    box-shadow: var(--shadow-sm);
}

.status-active {
    background: var(--success-gradient);
    color: white;
}

.status-completed {
    background: var(--info-gradient);
    color: white;
}

.status-pending,
.status-not-started {
    background: var(--warning-gradient);
    color: white;
}

.status-processing {
    background: var(--info-gradient);
    color: white;
}

.status-failed {
    background: var(--danger-gradient);
    color: white;
}

.status-paused {
    background: var(--secondary-gradient);
    color: white;
}

/* ===================================
   任务项样式
   =================================== */
.task-item {
    padding: var(--spacing-lg);
    margin: var(--spacing-md) 0;
    background: #f8fafc;
    border-left: 4px solid var(--primary-light);
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
}

.task-item:hover {
    box-shadow: var(--shadow-md);
    transform: translateX(2px);
}

.task-item.completed {
    border-left-color: var(--success-gradient);
    opacity: 0.7;
    background: #f0fdf4;
}

.task-item.completed .task-name {
    text-decoration: line-through;
    color: var(--text-tertiary);
}

.task-week {
    display: inline-flex;
    align-items: center;
    background: var(--primary-gradient);
    color: white;
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-sm);
    font-size: 11px;
    font-weight: 600;
    margin-right: var(--spacing-sm);
    box-shadow: var(--shadow-sm);
}

.task-type {
    display: inline-flex;
    align-items: center;
    background: var(--secondary-gradient);
    color: white;
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-sm);
    font-size: 11px;
    font-weight: 600;
}

/* ===================================
   警告提示
   =================================== */
.alert {
    padding: var(--spacing-lg) var(--spacing-xl);
    margin: var(--spacing-lg) 0;
    border-radius: var(--radius-md);
    border-left: 4px solid;
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    animation: slideDown var(--transition-base);
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.alert-success {
    background: #f0fdf4;
    color: #166534;
    border-color: #22c55e;
}

.alert-danger {
    background: #fef2f2;
    color: #991b1b;
    border-color: #ef4444;
}

.alert-info {
    background: #eff6ff;
    color: #1e40af;
    border-color: #3b82f6;
}

/* ===================================
   导航栏
   =================================== */
.navbar {
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg) var(--spacing-3xl);
    margin-bottom: var(--spacing-3xl);
    box-shadow: var(--shadow-sm);
    display: flex;
    justify-content: space-between;
    align-items: center;
    border: 1px solid var(--border-color);
}

.navbar-brand {
    font-size: 20px;
    font-weight: 700;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.5px;
}

.navbar-nav {
    display: flex;
    gap: var(--spacing-md);
}

/* ===================================
   计划卡片
   =================================== */
.plan-card {
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    padding: var(--spacing-3xl);
    margin-bottom: var(--spacing-xl);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
    border: 1px solid var(--border-color);
}

.plan-card:hover {
    box-shadow: var(--shadow-md);
    border-color: var(--primary-light);
}

.plan-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-xl);
    gap: var(--spacing-lg);
}

.plan-title {
    font-size: 20px;
    font-weight: 700;
    color: var(--text-primary);
}

.plan-meta {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
    margin: var(--spacing-xl) 0;
    padding: var(--spacing-xl);
    background: var(--primary-bg);
    border-radius: var(--radius-md);
}

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

.meta-label {
    font-size: 12px;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.meta-value {
    font-size: 14px;
    color: var(--text-primary);
    font-weight: 600;
}

/* ===================================
   模态框
   =================================== */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    animation: fadeIn var(--transition-base);
}

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

.modal.show {
    display: flex;
}

.modal-content {
    background: var(--card-bg);
    padding: var(--spacing-3xl);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    max-width: 400px;
    width: 90%;
    animation: modalSlideIn var(--transition-base);
}

@keyframes modalSlideIn {
    from {
        transform: translateY(-30px) scale(0.95);
        opacity: 0;
    }
    to {
        transform: translateY(0) scale(1);
        opacity: 1;
    }
}

.modal-actions {
    display: flex;
    gap: var(--spacing-md);
    margin-top: var(--spacing-xl);
    justify-content: flex-end;
}

/* ===================================
   空状态
   =================================== */
.empty-state {
    text-align: center;
    padding: 80px var(--spacing-xl);
    color: var(--text-secondary);
}

.empty-state-icon {
    font-size: 72px;
    margin-bottom: var(--spacing-xl);
    opacity: 0.6;
}

/* ===================================
   对话样式
   =================================== */
.chat-container {
    display: flex;
    flex-direction: column;
    height: calc(100vh - 300px);
    min-height: 500px;
}

.chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: var(--spacing-xl);
    background: #f8fafc;
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-lg);
    border: 1px solid var(--border-color);
}

.message {
    margin-bottom: var(--spacing-xl);
    display: flex;
    align-items: flex-start;
    animation: messageSlideIn var(--transition-base);
}

@keyframes messageSlideIn {
    from {
        opacity: 0;
        transform: translateY(15px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.message.user {
    flex-direction: row-reverse;
}

.message-avatar {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-full);
    background: var(--primary-gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 700;
    flex-shrink: 0;
    box-shadow: var(--shadow-sm);
}

.message.user .message-avatar {
    background: var(--success-gradient);
}

.message-content {
    max-width: 70%;
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-lg);
    margin: 0 var(--spacing-md);
    line-height: 1.6;
    box-shadow: var(--shadow-sm);
}

.message.assistant .message-content {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
}

.message.user .message-content {
    background: var(--primary-gradient);
    color: white;
}

/* Markdown 内容样式 */
.message-content h1,
.message-content h2,
.message-content h3,
.message-content h4 {
    margin-top: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
    font-weight: 600;
    color: inherit;
}

.message-content h1 { font-size: 1.8em; }
.message-content h2 { font-size: 1.5em; }
.message-content h3 { font-size: 1.3em; }
.message-content h4 { font-size: 1.1em; }

.message-content ul,
.message-content ol {
    margin: var(--spacing-md) 0;
    padding-left: var(--spacing-xl);
}

.message-content li {
    margin-bottom: var(--spacing-xs);
    line-height: 1.6;
}

.message-content li ul,
.message-content li ol {
    margin-top: var(--spacing-xs);
    margin-bottom: var(--spacing-xs);
}

.message-content p {
    margin: var(--spacing-md) 0;
}

.message-content strong {
    font-weight: 600;
}

.message-content em {
    font-style: italic;
}

.message-content code {
    background: rgba(0, 0, 0, 0.05);
    padding: 2px 6px;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    font-size: 0.9em;
}

.message-content pre {
    background: rgba(0, 0, 0, 0.05);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    overflow-x: auto;
    margin: var(--spacing-md) 0;
}

.message-content pre code {
    background: none;
    padding: 0;
}

.message-content hr {
    border: none;
    border-top: 2px solid var(--border-color);
    margin: var(--spacing-xl) 0;
}

.message-content blockquote {
    border-left: 4px solid var(--primary-light);
    padding-left: var(--spacing-md);
    margin: var(--spacing-md) 0;
    color: var(--text-secondary);
    font-style: italic;
}

.chat-input-area {
    display: flex;
    gap: var(--spacing-md);
}

.chat-input-area input {
    flex: 1;
}

/* ===================================
   响应式设计
   =================================== */
@media (max-width: 768px) {
    body {
        padding: var(--spacing-md);
    }

    .card {
        padding: var(--spacing-xl);
    }

    .navbar {
        flex-direction: column;
        gap: var(--spacing-md);
        padding: var(--spacing-lg);
    }

    .navbar-nav {
        flex-wrap: wrap;
        justify-content: center;
    }

    .plan-meta {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }

    .message-content {
        max-width: 85%;
    }

    .plan-header {
        flex-direction: column;
        align-items: flex-start;
    }

    h1 {
        font-size: 24px;
    }

    .chat-container {
        height: calc(100vh - 350px);
    }
}

/* ===================================
   实用工具类
   =================================== */
.text-center {
    text-align: center;
}

.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mt-xl { margin-top: var(--spacing-xl); }

.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }
.mb-xl { margin-bottom: var(--spacing-xl); }

.p-sm { padding: var(--spacing-sm); }
.p-md { padding: var(--spacing-md); }
.p-lg { padding: var(--spacing-lg); }
.p-xl { padding: var(--spacing-xl); }

/* ===================================
   右上角Toast通知
   =================================== */
.toast-container {
    position: fixed;
    top: var(--spacing-xl);
    right: var(--spacing-xl);
    z-index: 9999;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    max-width: 400px;
    pointer-events: none;
}

.toast {
    background: var(--card-bg);
    padding: var(--spacing-lg) var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    min-width: 300px;
    pointer-events: auto;
    animation: toastSlideIn 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border-left: 4px solid;
    position: relative;
    overflow: hidden;
}

@keyframes toastSlideIn {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

@keyframes toastSlideOut {
    from {
        transform: translateX(0);
        opacity: 1;
    }
    to {
        transform: translateX(100%);
        opacity: 0;
    }
}

.toast.toast-exit {
    animation: toastSlideOut 0.3s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

.toast-icon {
    font-size: 24px;
    flex-shrink: 0;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-full);
}

.toast-message {
    flex: 1;
    font-size: 14px;
    font-weight: 500;
    color: var(--text-primary);
    line-height: 1.4;
}

.toast-close {
    background: none;
    border: none;
    font-size: 18px;
    color: var(--text-tertiary);
    cursor: pointer;
    padding: var(--spacing-xs);
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
    flex-shrink: 0;
}

.toast-close:hover {
    background: var(--border-color);
    color: var(--text-primary);
}

/* Toast类型样式 */
.toast-success {
    border-left-color: #22c55e;
    background: linear-gradient(to right, #f0fdf4, #ffffff);
}

.toast-success .toast-icon {
    background: #dcfce7;
    color: #16a34a;
}

.toast-error {
    border-left-color: #ef4444;
    background: linear-gradient(to right, #fef2f2, #ffffff);
}

.toast-error .toast-icon {
    background: #fee2e2;
    color: #dc2626;
}

.toast-info {
    border-left-color: #3b82f6;
    background: linear-gradient(to right, #eff6ff, #ffffff);
}

.toast-info .toast-icon {
    background: #dbeafe;
    color: #2563eb;
}

.toast-warning {
    border-left-color: #f59e0b;
    background: linear-gradient(to right, #fffbeb, #ffffff);
}

.toast-warning .toast-icon {
    background: #fef3c7;
    color: #d97706;
}

/* Toast进度条 */
.toast-progress {
    position: absolute;
    bottom: 0;
    left: 0;
    height: 3px;
    background: currentColor;
    opacity: 0.3;
    animation: toastProgress 3s linear;
}

@keyframes toastProgress {
    from {
        width: 100%;
    }
    to {
        width: 0%;
    }
}

/* 响应式 */
@media (max-width: 768px) {
    .toast-container {
        top: var(--spacing-md);
        right: var(--spacing-md);
        left: var(--spacing-md);
        max-width: none;
    }

    .toast {
        min-width: auto;
        width: 100%;
    }
}