/* 全局样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #4CAF50;
    --secondary-color: #2196F3;
    --danger-color: #f44336;
    --text-color: #333;
    --text-light: #666;
    --border-color: #e0e0e0;
    --bg-color: #f5f5f5;
    --white: #ffffff;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.15);
}

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

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 顶部导航 */
.header {
    background: var(--white);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
}

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

.history-btn {
    background: none;
    border: none;
    color: var(--text-color);
    cursor: pointer;
    padding: 8px;
    border-radius: 50%;
    transition: background 0.3s;
}

.history-btn:hover {
    background: var(--bg-color);
}

/* 主内容 */
.main {
    padding: 20px 0;
}

.section {
    background: var(--white);
    border-radius: 12px;
    padding: 24px;
    margin-bottom: 20px;
    box-shadow: var(--shadow);
}

/* 上传区域 */
.subject-selector {
    margin-bottom: 24px;
    text-align: center;
}

.subject-selector label {
    display: block;
    font-size: 16px;
    font-weight: 500;
    margin-bottom: 12px;
    color: var(--text-color);
}

.subject-buttons {
    display: flex;
    gap: 12px;
    justify-content: center;
    flex-wrap: wrap;
}

.subject-btn {
    flex: 1;
    min-width: 80px;
    max-width: 120px;
    padding: 12px 8px;
    background: var(--white);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.3s;
    font-size: 13px;
    line-height: 1.4;
    text-align: center;
}

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

.subject-btn.active {
    background: var(--primary-color);
    border-color: var(--primary-color);
    color: var(--white);
}

.subject-icon {
    display: block;
    font-size: 24px;
    margin-bottom: 4px;
}

.upload-area {
    border: 2px dashed var(--border-color);
    border-radius: 12px;
    padding: 60px 20px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s;
    margin-bottom: 20px;
}

.upload-area:hover {
    border-color: var(--primary-color);
    background: rgba(76, 175, 80, 0.05);
}

.upload-content {
    pointer-events: none;
}

.upload-icon {
    color: var(--primary-color);
    margin-bottom: 16px;
}

.upload-area h2 {
    font-size: 20px;
    margin-bottom: 8px;
}

.upload-area p {
    color: var(--text-light);
    font-size: 14px;
}

/* 按钮 */
.button-group {
    display: flex;
    gap: 12px;
    justify-content: center;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s;
    flex: 1;
    max-width: 200px;
}

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

.btn-primary:hover {
    background: #45a049;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

.btn-secondary:hover {
    background: var(--bg-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-close {
    background: none;
    border: none;
    color: var(--text-color);
    cursor: pointer;
    padding: 4px;
}

/* 裁剪区域 */
.crop-container {
    max-height: 60vh;
    margin-bottom: 20px;
    overflow: hidden;
    border-radius: 8px;
}

.crop-container img {
    max-width: 100%;
    display: block;
}

/* 加载动画 */
.loading {
    text-align: center;
    padding: 40px 20px;
}

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

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

.loading p {
    color: var(--text-light);
    font-size: 16px;
}

/* 结果展示 */
.result-card {
    animation: fadeIn 0.5s;
}

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

.result-image {
    margin-bottom: 24px;
    border-radius: 8px;
    overflow: hidden;
}

.result-image img {
    width: 100%;
    display: block;
}

.result-item {
    margin-bottom: 24px;
}

.result-item:last-child {
    margin-bottom: 0;
}

.result-title {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 8px;
}

.result-title::before {
    content: '';
    width: 4px;
    height: 20px;
    background: var(--primary-color);
    border-radius: 2px;
}

.result-text {
    background: var(--bg-color);
    padding: 16px;
    border-radius: 8px;
    line-height: 1.8;
    white-space: pre-wrap;
    word-wrap: break-word;
}

.answer-text {
    background: #e8f5e9;
    color: #2e7d32;
    font-weight: 500;
    font-size: 16px;
}

/* 历史记录 */
.history-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--border-color);
}

.history-header h2 {
    font-size: 20px;
}

.history-filter {
    display: flex;
    gap: 8px;
    margin-bottom: 20px;
    overflow-x: auto;
    padding-bottom: 4px;
}

.filter-btn {
    padding: 8px 16px;
    background: var(--white);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    font-size: 14px;
    cursor: pointer;
    transition: all 0.3s;
    white-space: nowrap;
    flex-shrink: 0;
}

.filter-btn:hover {
    border-color: var(--primary-color);
    background: rgba(76, 175, 80, 0.1);
}

.filter-btn.active {
    background: var(--primary-color);
    border-color: var(--primary-color);
    color: var(--white);
}

.history-list {
    max-height: 70vh;
    overflow-y: auto;
}

.history-item {
    display: flex;
    gap: 16px;
    padding: 16px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    margin-bottom: 12px;
    cursor: pointer;
    transition: all 0.3s;
    position: relative;
}

.history-item:hover {
    box-shadow: var(--shadow);
    transform: translateY(-2px);
}

.delete-btn {
    position: absolute;
    top: 12px;
    right: 12px;
    background: var(--danger-color);
    color: var(--white);
    border: none;
    border-radius: 6px;
    padding: 8px;
    cursor: pointer;
    transition: all 0.3s;
    opacity: 0;
    transform: scale(0.9);
}

.history-item:hover .delete-btn {
    opacity: 1;
    transform: scale(1);
}

.delete-btn:hover {
    background: #d32f2f;
    transform: scale(1.1);
}

.history-item-image {
    width: 100px;
    height: 100px;
    flex-shrink: 0;
    border-radius: 8px;
    overflow: hidden;
    background: var(--bg-color);
}

.history-item-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.history-item-content {
    flex: 1;
    min-width: 0;
}

.history-item-question {
    font-weight: 500;
    margin-bottom: 8px;
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
}

.history-item-answer {
    color: var(--text-light);
    font-size: 14px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.history-item-time {
    color: var(--text-light);
    font-size: 12px;
    margin-top: 8px;
}

.history-empty {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-light);
}

.history-empty svg {
    width: 80px;
    height: 80px;
    margin-bottom: 16px;
    opacity: 0.3;
}

/* Toast 提示 */
.toast {
    position: fixed;
    top: 80px;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(0, 0, 0, 0.8);
    color: var(--white);
    padding: 12px 24px;
    border-radius: 8px;
    font-size: 14px;
    z-index: 1000;
    opacity: 0;
    transition: opacity 0.3s;
    pointer-events: none;
}

.toast.show {
    opacity: 1;
}

/* 删除确认弹窗 */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.6);
    z-index: 2000;
    justify-content: center;
    align-items: center;
    animation: fadeIn 0.3s;
}

.modal-content {
    background: var(--white);
    padding: 32px;
    border-radius: 12px;
    max-width: 400px;
    width: 90%;
    box-shadow: var(--shadow-lg);
    animation: slideUp 0.3s;
}

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

.modal-content h3 {
    margin: 0 0 16px 0;
    font-size: 20px;
    color: var(--text-color);
}

.modal-content p {
    margin: 0 0 20px 0;
    color: var(--text-light);
    font-size: 14px;
}

.modal-input {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 16px;
    margin-bottom: 20px;
    outline: none;
    transition: border-color 0.3s;
}

.modal-input:focus {
    border-color: var(--primary-color);
}

.modal-buttons {
    display: flex;
    gap: 12px;
    justify-content: flex-end;
}

.modal-buttons .btn {
    flex: 1;
    max-width: 120px;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 0 16px;
    }

    .section {
        padding: 20px 16px;
        border-radius: 0;
    }

    .upload-area {
        padding: 40px 16px;
    }

    .button-group {
        flex-direction: column;
    }

    .btn {
        max-width: 100%;
    }

    .history-item {
        flex-direction: column;
    }

    .history-item-image {
        width: 100%;
        height: 200px;
    }
}

/* 滚动条样式 */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-color);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #999;
}