/* ─── 基础变量 ──────────────────────────────────────────── */
:root {
    --color-primary: #4285f4;
    --color-primary-hover: #3367d6;
    --color-primary-light: #e8f0fe;
    --color-bg: #f8f9fa;
    --color-surface: #ffffff;
    --color-text: #202124;
    --color-text-secondary: #5f6368;
    --color-text-placeholder: #9aa0a6;
    --color-border: #dadce0;
    --color-border-focus: #4285f4;
    --color-success: #0d904f;
    --color-error: #d93025;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.06), 0 1px 3px rgba(0,0,0,0.1);
    --shadow-md: 0 1px 3px rgba(0,0,0,0.08), 0 4px 12px rgba(0,0,0,0.12);
    --shadow-lg: 0 2px 6px rgba(0,0,0,0.08), 0 8px 24px rgba(0,0,0,0.15);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --transition: 0.2s ease;
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Noto Sans SC', 'Noto Sans', sans-serif;
}

/* ─── Reset ────────────────────────────────────────────── */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: var(--font-family);
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ─── 无障碍辅助 ──────────────────────────────────────── */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0,0,0,0);
    white-space: nowrap;
    border: 0;
}

/* ─── Header ───────────────────────────────────────────── */
.app-header {
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    padding: 20px 24px;
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
}

.logo {
    font-size: 24px;
    font-weight: 600;
    color: var(--color-text);
    display: flex;
    align-items: center;
    gap: 8px;
}

.logo-link {
    text-decoration: none;
    color: inherit;
    display: flex;
    align-items: center;
    gap: 8px;
}

.logo-link:hover {
    opacity: 0.8;
}

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

.logo-light {
    font-weight: 400;
    color: var(--color-text-secondary);
}

.subtitle {
    font-size: 14px;
    color: var(--color-text-secondary);
    margin-top: 4px;
}

/* ─── Main ─────────────────────────────────────────────── */
.app-main {
    flex: 1;
    max-width: 1200px;
    width: 100%;
    margin: 0 auto;
    padding: 24px;
}

/* ─── 选项卡 ──────────────────────────────────────────── */
.tab-bar {
    display: flex;
    gap: 4px;
    margin-bottom: 20px;
    background: var(--color-surface);
    border-radius: var(--radius-md);
    padding: 4px;
    box-shadow: var(--shadow-sm);
}

.tab-btn {
    flex: 1;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 20px;
    font-size: 15px;
    font-weight: 500;
    font-family: var(--font-family);
    color: var(--color-text-secondary);
    background: transparent;
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition);
}

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

.tab-btn.active {
    background: var(--color-primary);
    color: #fff;
    box-shadow: var(--shadow-sm);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* ─── 翻译卡片 ────────────────────────────────────────── */
.translator-card {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    overflow: hidden;
}

/* ─── 语言选择栏 ──────────────────────────────────────── */
.lang-bar {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 16px 20px;
    border-bottom: 1px solid var(--color-border);
    background: var(--color-bg);
}

.lang-select-wrapper {
    flex: 1;
}

.lang-select {
    width: 100%;
    padding: 10px 14px;
    font-size: 15px;
    font-family: var(--font-family);
    color: var(--color-text);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: border-color var(--transition), box-shadow var(--transition);
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%235f6368' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
    padding-right: 32px;
}

.lang-select:hover {
    border-color: var(--color-text-secondary);
}

.lang-select:focus {
    outline: none;
    border-color: var(--color-border-focus);
    box-shadow: 0 0 0 3px rgba(66, 133, 244, 0.15);
}

/* ─── 交换按钮 ────────────────────────────────────────── */
.swap-btn {
    flex-shrink: 0;
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--color-border);
    border-radius: 50%;
    background: var(--color-surface);
    color: var(--color-text-secondary);
    cursor: pointer;
    transition: all var(--transition);
}

.swap-btn:hover {
    background: var(--color-primary-light);
    color: var(--color-primary);
    border-color: var(--color-primary);
}

.swap-btn:active {
    transform: rotate(180deg);
}

/* ─── 翻译面板 ────────────────────────────────────────── */
.panels {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
}

.panel-divider {
    width: 1px;
    background: var(--color-border);
}

.panel {
    display: flex;
    flex-direction: column;
    min-height: 240px;
}

.text-area {
    flex: 1;
    width: 100%;
    min-height: 200px;
    padding: 20px;
    font-size: 18px;
    font-family: var(--font-family);
    color: var(--color-text);
    background: transparent;
    border: none;
    resize: vertical;
    line-height: 1.6;
}

textarea.text-area {
    outline: none;
}

textarea.text-area::placeholder {
    color: var(--color-text-placeholder);
}

.result-area {
    overflow-y: auto;
    white-space: pre-wrap;
    word-break: break-word;
}

.placeholder-text {
    color: var(--color-text-placeholder);
    font-style: italic;
}

/* ─── 面板底部 ────────────────────────────────────────── */
.panel-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 8px 16px;
    border-top: 1px solid var(--color-border);
    background: var(--color-bg);
    min-height: 44px;
}

.char-count {
    font-size: 13px;
    color: var(--color-text-secondary);
}

.status-text {
    font-size: 13px;
    color: var(--color-text-secondary);
}

.status-text.error {
    color: var(--color-error);
}

.status-text.success {
    color: var(--color-success);
}

.icon-btn {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 6px 12px;
    font-size: 13px;
    font-family: var(--font-family);
    color: var(--color-text-secondary);
    background: transparent;
    border: 1px solid transparent;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition);
}

.icon-btn:hover {
    background: var(--color-primary-light);
    color: var(--color-primary);
    border-color: var(--color-primary-light);
}

/* ─── 翻译按钮 ────────────────────────────────────────── */
.translate-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 180px;
    padding: 12px 32px;
    font-size: 16px;
    font-weight: 500;
    font-family: var(--font-family);
    color: #fff;
    background: var(--color-primary);
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition);
    box-shadow: var(--shadow-sm);
}

.translate-btn:hover {
    background: var(--color-primary-hover);
    box-shadow: var(--shadow-md);
}

.translate-btn:active {
    transform: translateY(1px);
}

.translate-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

/* ─── OCR 勾选框 ─────────────────────────────────────── */
.ocr-toggle {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    font-size: 13px;
    color: var(--color-text-secondary);
    margin-right: 16px;
    user-select: none;
}

.ocr-toggle input[type="checkbox"] {
    width: 16px;
    height: 16px;
    accent-color: var(--color-primary);
    cursor: pointer;
}

.ocr-toggle-label {
    white-space: nowrap;
}

.ocr-disabled {
    opacity: 0.45;
    cursor: not-allowed;
}

.ocr-disabled input[type="checkbox"] {
    cursor: not-allowed;
}

.action-bar {
    padding: 16px 20px;
    border-top: 1px solid var(--color-border);
    text-align: center;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    flex-wrap: wrap;
}

/* ─── Loading Spinner ─────────────────────────────────── */
.spinner {
    display: inline-block;
    width: 16px;
    height: 16px;
    border: 2px solid rgba(255,255,255,0.3);
    border-top-color: #fff;
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
    margin-right: 8px;
    vertical-align: middle;
}

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

/* ─── 图片上传区域 ────────────────────────────────────── */
.image-upload-section {
    padding: 20px;
}

.upload-zone {
    border: 2px dashed var(--color-border);
    border-radius: var(--radius-md);
    padding: 40px 20px;
    text-align: center;
    cursor: pointer;
    transition: all var(--transition);
    min-height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

.upload-zone:hover {
    border-color: var(--color-primary);
    background: var(--color-primary-light);
}

.upload-zone.drag-over {
    border-color: var(--color-primary);
    background: var(--color-primary-light);
    box-shadow: inset 0 0 0 2px var(--color-primary);
}

.upload-placeholder {
    color: var(--color-text-secondary);
}

.upload-placeholder svg {
    margin-bottom: 12px;
    opacity: 0.6;
}

.upload-text {
    font-size: 16px;
    font-weight: 500;
    margin-bottom: 4px;
}

.upload-hint {
    font-size: 13px;
    color: var(--color-text-placeholder);
}

.preview-image {
    max-width: 100%;
    max-height: 400px;
    object-fit: contain;
    border-radius: var(--radius-sm);
}

.upload-actions {
    padding: 8px 0 0;
    text-align: right;
}

/* ─── 图片翻译结果区域 ───────────────────────────────── */
.image-result-section {
    border-top: 1px solid var(--color-border);
}

.image-result-area {
    min-height: 120px;
    max-height: 400px;
    padding: 20px;
    overflow-y: auto;
}

/* ─── PDF 上传区域 ────────────────────────────────────── */
.pdf-upload-section {
    padding: 20px;
}

.pdf-progress {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    padding: 40px 20px;
    color: var(--color-text-secondary);
    font-size: 15px;
}

.pdf-progress .spinner {
    border-color: rgba(66, 133, 244, 0.2);
    border-top-color: var(--color-primary);
    width: 24px;
    height: 24px;
}

/* ═══════════ PDF 浏览器 ═══════════ */

.pdf-main {
    max-width: 1400px;
}

/* ─── PDF 控制栏 ──────────────────────────────────────── */
.pdf-control-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    background: var(--color-surface);
    border-radius: var(--radius-md);
    padding: 12px 20px;
    box-shadow: var(--shadow-sm);
    margin-bottom: 16px;
    flex-wrap: wrap;
}

.pdf-lang-bar {
    display: flex;
    align-items: center;
    gap: 8px;
    flex: 1;
    min-width: 300px;
}

.lang-arrow {
    font-size: 18px;
    color: var(--color-text-secondary);
    flex-shrink: 0;
}

.pdf-page-nav {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-shrink: 0;
}

.nav-btn {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    background: var(--color-surface);
    color: var(--color-text-secondary);
    cursor: pointer;
    transition: all var(--transition);
}

.nav-btn:hover:not(:disabled) {
    background: var(--color-primary-light);
    color: var(--color-primary);
    border-color: var(--color-primary);
}

.nav-btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

.page-info {
    font-size: 15px;
    font-weight: 500;
    color: var(--color-text);
    white-space: nowrap;
}

/* ─── PDF 双栏视图 ────────────────────────────────────── */
.pdf-viewer {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    overflow: hidden;
    min-height: 70vh;
}

.pdf-panel {
    display: flex;
    flex-direction: column;
}

.pdf-panel-divider {
    width: 1px;
    background: var(--color-border);
}

.pdf-panel-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 20px;
    font-size: 14px;
    font-weight: 600;
    color: var(--color-text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
}

.pdf-panel-content {
    flex: 1;
    overflow-y: auto;
    position: relative;
}

.pdf-page-image {
    width: 100%;
    height: auto;
    display: block;
}

.pdf-translation-text {
    padding: 24px;
    font-size: 16px;
    line-height: 1.8;
    white-space: pre-wrap;
    word-break: break-word;
    min-height: 200px;
}

.error-text {
    color: var(--color-error);
}

.pdf-translate-loading {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    padding: 40px 20px;
    color: var(--color-text-secondary);
    font-size: 15px;
}

.pdf-translate-loading .spinner {
    border-color: rgba(66, 133, 244, 0.2);
    border-top-color: var(--color-primary);
    width: 20px;
    height: 20px;
}

/* ─── 说明卡片 ────────────────────────────────────────── */
.info-card {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    padding: 24px 28px;
    margin-top: 24px;
}

.info-card h2 {
    font-size: 18px;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 16px;
}

.api-section {
    margin-bottom: 16px;
}

.api-section:last-child {
    margin-bottom: 0;
}

.api-section h3 {
    font-size: 14px;
    font-weight: 600;
    color: var(--color-text-secondary);
    margin-bottom: 6px;
}

.api-section p {
    font-size: 14px;
    color: var(--color-text-secondary);
    margin-top: 4px;
}

.api-url {
    display: block;
    padding: 10px 14px;
    font-size: 14px;
    font-family: 'Cascadia Code', 'Fira Code', 'Consolas', monospace;
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    color: var(--color-text);
    word-break: break-all;
}

.code-block {
    display: block;
    padding: 10px 14px;
    font-size: 14px;
    font-family: 'Cascadia Code', 'Fira Code', 'Consolas', monospace;
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    color: var(--color-text);
    white-space: pre-wrap;
    word-break: break-all;
}

/* ─── 重新翻译按钮 ─────────────────────────────────────── */
.retranslate-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 10px 20px;
    font-size: 14px;
    font-weight: 500;
    font-family: var(--font-family);
    color: var(--color-primary);
    background: var(--color-primary-light);
    border: 1px solid var(--color-primary);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition);
}

.retranslate-btn:hover {
    background: var(--color-primary);
    color: #fff;
}

.retranslate-btn:active {
    transform: translateY(1px);
}

.retranslate-btn-sm {
    padding: 6px 12px;
    font-size: 13px;
}

/* ─── OCR 区域 ─────────────────────────────────────────── */
.ocr-section {
    border-top: 1px solid var(--color-border);
}

.ocr-section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 8px 16px;
    background: #fef7e0;
    border-bottom: 1px solid #f0dfa0;
}

.ocr-section-title {
    font-size: 13px;
    font-weight: 600;
    color: #8a6d00;
}

.ocr-section-actions {
    display: flex;
    gap: 4px;
}

.ocr-text-area {
    min-height: 80px;
    max-height: 200px;
    padding: 12px 16px;
    font-size: 14px;
    overflow-y: auto;
    background: #fffdf5;
}

/* ─── PDF OCR 区域 ─────────────────────────────────────── */
.pdf-ocr-section {
    border-bottom: 2px solid #f0dfa0;
}

.pdf-ocr-section .ocr-section-header {
    padding: 8px 16px;
}

.pdf-ocr-text {
    padding: 16px;
    font-size: 14px;
    line-height: 1.6;
    white-space: pre-wrap;
    word-break: break-word;
    max-height: 200px;
    overflow-y: auto;
    background: #fffdf5;
}

/* ─── 语言选择闪烁动画 ─────────────────────────────────── */
@keyframes flash-attention {
    0%   { box-shadow: 0 0 0 0 rgba(217, 48, 37, 0.4); border-color: var(--color-error); }
    25%  { box-shadow: 0 0 0 6px rgba(217, 48, 37, 0.2); border-color: var(--color-error); }
    50%  { box-shadow: 0 0 0 0 rgba(217, 48, 37, 0.4); border-color: var(--color-error); }
    75%  { box-shadow: 0 0 0 6px rgba(217, 48, 37, 0.2); border-color: var(--color-error); }
    100% { box-shadow: 0 0 0 0 transparent; border-color: var(--color-border); }
}

.flash-attention {
    animation: flash-attention 1.5s ease-out;
}

.lang-select.auto-detected {
    border-color: var(--color-success);
}

.lang-select.auto-unknown {
    border-color: #e8a000;
}

/* ─── Footer ───────────────────────────────────────────── */
.app-footer {
    text-align: center;
    padding: 20px 24px;
    font-size: 13px;
    color: var(--color-text-secondary);
    border-top: 1px solid var(--color-border);
}

.app-footer a {
    color: var(--color-primary);
    text-decoration: none;
}

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

/* ─── 密钥验证页 ─────────────────────────────────────── */
.auth-card {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    padding: 48px 36px;
    max-width: 420px;
    margin: 60px auto 0;
    text-align: center;
}

.auth-icon {
    color: var(--color-text-secondary);
    margin-bottom: 16px;
}

.auth-title {
    font-size: 22px;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 8px;
}

.auth-desc {
    font-size: 14px;
    color: var(--color-text-secondary);
    margin-bottom: 28px;
    line-height: 1.6;
}

.auth-form {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.auth-input {
    width: 100%;
    padding: 12px 16px;
    font-size: 16px;
    font-family: var(--font-family);
    color: var(--color-text);
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    text-align: center;
    letter-spacing: 2px;
    transition: border-color var(--transition), box-shadow var(--transition);
}

.auth-input:focus {
    outline: none;
    border-color: var(--color-border-focus);
    box-shadow: 0 0 0 3px rgba(66, 133, 244, 0.15);
}

.auth-btn {
    width: 100%;
}

.auth-error {
    font-size: 14px;
    color: var(--color-error);
    margin-top: 4px;
}

/* ─── 响应式 ──────────────────────────────────────────── */
@media (max-width: 768px) {
    .app-main {
        padding: 16px;
    }

    .lang-bar {
        flex-direction: column;
        gap: 8px;
    }

    .swap-btn {
        transform: rotate(90deg);
    }

    .swap-btn:active {
        transform: rotate(270deg);
    }

    .panels {
        grid-template-columns: 1fr;
    }

    .panel-divider {
        width: 100%;
        height: 1px;
    }

    .text-area {
        min-height: 150px;
        font-size: 16px;
    }

    .logo {
        font-size: 20px;
    }

    /* 选项卡响应式 */
    .tab-btn {
        padding: 10px 12px;
        font-size: 13px;
        gap: 4px;
    }

    .tab-btn svg {
        width: 16px;
        height: 16px;
    }

    /* PDF 浏览器响应式 */
    .pdf-viewer {
        grid-template-columns: 1fr;
        min-height: auto;
    }

    .pdf-panel-divider {
        width: 100%;
        height: 1px;
    }

    .pdf-control-bar {
        flex-direction: column;
        align-items: stretch;
    }

    .pdf-lang-bar {
        min-width: auto;
    }

    .pdf-page-nav {
        justify-content: center;
    }
}