:root {
    --bg-color: #F4F1ED;
    --surface-color: #EAE5DD;
    --text-main: #5C5855;
    --text-muted: #8A8580;
    --accent-color: #929D96;
    --accent-hover: #7A867F;
    --border-radius: 14px;
    --border-color: #D6D2C9;
    --shadow: 0 4px 12px rgba(0,0,0,0.05);
    --danger-color: #C09891;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg-color: #2D2D2D;
        --surface-color: #353535;
        --text-main: #D4D4D4;
        --text-muted: #9E9E9E;
        --accent-color: #6C7A74;
        --accent-hover: #83928B;
        --border-color: #4A4A4A;
        --shadow: 0 4px 12px rgba(0,0,0,0.2);
        --danger-color: #9C726B;
    }
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.6;
    min-height: 100vh;
    transition: background-color 0.3s, color 0.3s;
}

.view-container {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

#reader-view {
    height: 100vh;
    overflow: hidden;
}

.hidden { display: none !important; }

/* ---- 首页 ---- */
.page-header { text-align: center; padding: 60px 20px 40px; }
.page-header p { color: var(--text-muted); margin-top: 8px; }

.list-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 20px 60px;
    width: 100%;
}

.toolbar { display: flex; gap: 12px; margin-bottom: 24px; flex-wrap: wrap; }

.primary-btn {
    background-color: var(--accent-color);
    color: #fff;
    border: none;
    padding: 10px 20px;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 0.95rem;
    transition: background-color 0.2s;
    white-space: nowrap;
}
.primary-btn:hover { background-color: var(--accent-hover); }
.primary-btn.secondary { background-color: transparent; color: var(--accent-color); border: 1px solid var(--border-color); }
.primary-btn.secondary:hover { background-color: var(--surface-color); }
.primary-btn.small { padding: 8px 16px; font-size: 0.9rem; }

/* ---- 文档组 ---- */
.group-list { display: flex; flex-direction: column; gap: 20px; }
.doc-group { background-color: var(--surface-color); border-radius: var(--border-radius); box-shadow: var(--shadow); overflow: hidden; }

.group-header {
    display: flex; align-items: center; padding: 16px 20px;
    cursor: pointer; user-select: none; gap: 10px;
    transition: background-color 0.15s;
}
.group-header:hover { background-color: var(--border-color); }

.group-toggle { font-size: 0.7rem; color: var(--text-muted); width: 16px; text-align: center; flex-shrink: 0; }
.group-name { font-weight: 600; font-size: 1.05rem; flex: 1; }
.group-count { font-size: 0.8rem; color: var(--text-muted); background-color: var(--bg-color); padding: 2px 10px; border-radius: 20px; }

.group-actions { display: flex; gap: 4px; margin-left: auto; opacity: 0; transition: opacity 0.15s; }
.group-header:hover .group-actions { opacity: 1; }

.icon-btn {
    background: none; border: none; color: var(--text-muted);
    font-size: 1rem; padding: 4px 8px; cursor: pointer;
    border-radius: 8px; transition: background-color 0.15s, color 0.15s;
}
.icon-btn:hover { background-color: var(--bg-color); color: var(--text-main); }
.icon-btn.danger:hover { color: var(--danger-color); }

.group-add-form {
    display: flex; gap: 10px; padding: 12px 20px;
    border-top: 1px solid var(--border-color);
    background-color: var(--bg-color); flex-wrap: wrap;
}
.group-add-form input {
    flex: 1; min-width: 160px; padding: 8px 12px;
    border: 1px solid var(--border-color); border-radius: 8px;
    background-color: var(--surface-color); color: var(--text-main);
    outline: none; font-size: 0.9rem;
}
.group-add-form input:focus { border-color: var(--accent-color); }

.doc-group .doc-list { list-style: none; padding: 0; }

.doc-item {
    padding: 14px 20px; display: flex; justify-content: space-between;
    align-items: center; cursor: pointer; transition: background-color 0.15s;
    border-top: 1px solid var(--border-color);
}
.doc-item:hover { background-color: var(--border-color); }
.doc-info { flex: 1; overflow: hidden; }
.doc-info h3 { font-size: 1rem; margin-bottom: 2px; }
.doc-info p { font-size: 0.8rem; color: var(--text-muted); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }

.delete-btn {
    background: none; border: none; color: var(--text-muted);
    font-size: 1.1rem; padding: 6px; cursor: pointer; border-radius: 8px;
    transition: color 0.15s, background-color 0.15s; flex-shrink: 0;
}
.delete-btn:hover { color: var(--danger-color); background-color: var(--bg-color); }

/* ---- 阅读器分栏布局 ---- */
.reader-nav {
    background-color: var(--surface-color);
    padding: 14px 24px;
    display: flex; align-items: center;
    box-shadow: var(--shadow); z-index: 100; flex-shrink: 0;
    gap: 12px;
}

.nav-btn {
    background: none; border: none; color: var(--accent-color);
    font-size: 1rem; cursor: pointer; font-weight: bold;
}
.nav-btn:hover { color: var(--accent-hover); }

.chat-toggle-nav { margin-left: auto; font-weight: 500; }

.doc-title-display {
    font-weight: bold; color: var(--text-main);
    white-space: nowrap; overflow: hidden; text-overflow: ellipsis; flex: 1;
}

.reader-split {
    display: flex; flex: 1; overflow: hidden; position: relative;
}

.reader-doc-pane {
    flex: 1; overflow-y: auto; display: flex; justify-content: center;
    min-width: 0;
}

.markdown-body {
    max-width: 960px; width: 100%; padding: 40px 60px; margin: 0 20px;
}

/* ---- 拖动分割线 ---- */
.reader-divider {
    width: 6px; cursor: col-resize; background-color: var(--border-color);
    flex-shrink: 0; transition: background-color 0.2s; border-radius: 3px;
    position: relative;
    z-index: 10;
}
.reader-divider:hover,
.reader-divider.dragging { background-color: var(--accent-color); }

/* ---- AI 聊天面板（桌面） ---- */
.reader-chat-pane {
    display: flex; flex-direction: column;
    background-color: var(--surface-color);
    overflow: hidden; transition: width 0.3s ease;
    border-radius: 0 0 0 var(--border-radius);
    height: 100%;
    max-height: 100vh;
}

/* ---- AI 聊天面板（移动端全屏弹窗） ---- */
.chat-mobile-overlay {
    position: fixed; inset: 0; z-index: 500;
    background-color: rgba(0,0,0,0.3);
    opacity: 0; transition: opacity 0.3s ease;
    pointer-events: none;
}
.chat-mobile-overlay.show {
    opacity: 1; pointer-events: auto;
}
.chat-mobile-panel {
    position: absolute; bottom: 0; left: 0; right: 0;
    height: 92vh; max-height: 92vh;
    background-color: var(--surface-color);
    border-radius: var(--border-radius) var(--border-radius) 0 0;
    display: flex; flex-direction: column;
    transform: translateY(100%); transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 -4px 24px rgba(0,0,0,0.12);
}
.chat-mobile-overlay.show .chat-mobile-panel {
    transform: translateY(0);
}

/* ---- 聊天通用样式 ---- */
.chat-header {
    display: flex; align-items: center; justify-content: space-between;
    padding: 14px 18px; border-bottom: 1px solid var(--border-color); flex-shrink: 0;
}
.chat-title { font-weight: 600; font-size: 1.05rem; }
.chat-header-actions { display: flex; gap: 2px; }

.chat-token-bar {
    padding: 8px 18px; border-bottom: 1px solid var(--border-color); flex-shrink: 0;
}
.token-info { font-size: 0.78rem; color: var(--text-muted); margin-bottom: 4px; }
.token-track {
    height: 4px; background-color: var(--bg-color); border-radius: 2px; overflow: hidden;
}
.token-fill {
    height: 100%; background-color: var(--accent-color); border-radius: 2px;
    width: 0%; transition: width 0.3s ease;
}
.token-fill.warn { background-color: #d4a74a; }
.token-fill.danger { background-color: var(--danger-color); }

.chat-messages {
    flex: 1; overflow-y: auto; padding: 16px;
    display: flex; flex-direction: column; gap: 12px;
}

.chat-welcome { text-align: center; color: var(--text-muted); padding: 40px 20px; font-size: 0.95rem; }
.chat-welcome-hint { font-size: 0.85rem; margin-top: 8px; opacity: 0.7; }

.chat-msg {
    padding: 10px 14px; border-radius: var(--border-radius);
    max-width: 92%; font-size: 0.92rem; line-height: 1.6; word-break: break-word;
}
.chat-msg-user {
    align-self: flex-end; background-color: var(--accent-color);
    color: #fff; border-bottom-right-radius: 4px;
}
.chat-msg-user p { margin: 0; }
.chat-msg-assistant {
    align-self: flex-start; background-color: var(--bg-color);
    color: var(--text-main); border-bottom-left-radius: 4px;
}
.chat-msg-assistant.streaming::after {
    content: '▍'; animation: blink 0.8s infinite;
}

.chat-msg-assistant p { margin: 0.4em 0; }
.chat-msg-assistant pre {
    background-color: var(--surface-color); padding: 10px;
    border-radius: 10px; overflow-x: auto; font-size: 0.85rem; margin: 0.6em 0;
}
.chat-msg-assistant code { font-family: Consolas, Monaco, monospace; font-size: 0.88em; }
.chat-msg-assistant blockquote {
    border-left: 3px solid var(--accent-color); padding-left: 10px;
    margin: 0.5em 0; color: var(--text-muted);
}
.chat-msg-assistant .math-display { text-align: left; margin: 0.5em 0; }
.chat-msg-assistant .math-inline { padding: 0 2px; }

@keyframes blink { 50% { opacity: 0; } }

.chat-input-area {
    border-top: 1px solid var(--border-color);
    padding: 12px 16px; flex-shrink: 0; background-color: var(--surface-color);
}
.chat-model-info { display: flex; align-items: center; gap: 12px; margin-bottom: 8px; }

.chat-select {
    flex: 1; padding: 6px 10px; border: 1px solid var(--border-color);
    border-radius: 8px; background-color: var(--bg-color);
    color: var(--text-main); font-size: 0.85rem; outline: none;
}

.chat-toggle-label {
    display: flex; align-items: center; gap: 4px;
    font-size: 0.85rem; color: var(--text-muted); cursor: pointer;
}
.chat-toggle-label input { accent-color: var(--accent-color); }

.chat-input-row { display: flex; gap: 8px; align-items: flex-end; }

#chat-input, #chat-input-m {
    flex: 1; padding: 10px 14px; border: 1px solid var(--border-color);
    border-radius: var(--border-radius); background-color: var(--bg-color);
    color: var(--text-main); outline: none; font-size: 0.92rem;
    font-family: inherit; resize: none; max-height: 120px; line-height: 1.5;
}
#chat-input:focus, #chat-input-m:focus { border-color: var(--accent-color); }

.chat-send-btn {
    width: 40px; height: 40px; border-radius: 50%;
    background-color: var(--accent-color); color: #fff; border: none;
    font-size: 1rem; cursor: pointer; flex-shrink: 0;
    transition: background-color 0.2s;
    display: flex; align-items: center; justify-content: center;
}
.chat-send-btn:hover { background-color: var(--accent-hover); }
.chat-send-btn.disabled { opacity: 0.5; cursor: not-allowed; }

/* ---- 选区浮窗 ---- */
.selection-tooltip { position: fixed; z-index: 250; transform: translateX(-50%); }
.selection-tooltip button {
    background-color: var(--accent-color); color: #fff; border: none;
    padding: 6px 14px; border-radius: 20px; font-size: 0.85rem;
    cursor: pointer; box-shadow: 0 2px 8px rgba(0,0,0,0.15);
    white-space: nowrap; transition: background-color 0.2s;
}
.selection-tooltip button:hover { background-color: var(--accent-hover); }

/* ---- 模态弹窗 ---- */
.modal-overlay {
    position: fixed; inset: 0; background-color: rgba(0,0,0,0.4);
    z-index: 600; display: flex; align-items: center; justify-content: center; padding: 20px;
}
.modal {
    background-color: var(--surface-color); border-radius: var(--border-radius);
    box-shadow: 0 8px 32px rgba(0,0,0,0.15); width: 100%; max-width: 480px; max-height: 80vh; overflow-y: auto;
}
.modal-header {
    display: flex; align-items: center; justify-content: space-between;
    padding: 20px 24px; border-bottom: 1px solid var(--border-color);
}
.modal-header h3 { font-size: 1.1rem; }
.modal-body { padding: 24px; }
.modal-footer {
    padding: 16px 24px; border-top: 1px solid var(--border-color);
    display: flex; justify-content: flex-end; gap: 10px;
}

.form-group { margin-bottom: 20px; }
.form-group:last-child { margin-bottom: 0; }
.form-group label { display: block; font-weight: 600; margin-bottom: 6px; font-size: 0.95rem; }

.form-input {
    width: 100%; padding: 10px 14px; border: 1px solid var(--border-color);
    border-radius: 8px; background-color: var(--bg-color);
    color: var(--text-main); font-size: 0.92rem; font-family: inherit;
    outline: none; resize: vertical;
}
.form-input:focus { border-color: var(--accent-color); }
.form-hint { font-size: 0.82rem; color: var(--text-muted); margin-top: 4px; }

/* ---- Markdown 排版 ---- */
.markdown-body h1, .markdown-body h2, .markdown-body h3 {
    margin-top: 1.5em; margin-bottom: 0.6em;
    border-bottom: 1px solid var(--border-color); padding-bottom: 0.3em;
}
.markdown-body pre {
    background-color: var(--bg-color); padding: 16px;
    border-radius: var(--border-radius); overflow-x: auto; margin: 1.2em 0;
}
.markdown-body code { font-family: Consolas, Monaco, monospace; border-radius: 4px; }
.markdown-body img {
    max-width: 100%; border-radius: var(--border-radius);
    display: block; margin: 1em auto;
    cursor: pointer; transition: outline 0.2s, box-shadow 0.2s;
}
.markdown-body img:hover { outline: 2px solid var(--accent-color); outline-offset: 2px; }
.markdown-body img.image-selected {
    outline: 2px solid var(--accent-color); outline-offset: 2px;
    box-shadow: 0 0 0 4px rgba(146,157,150,0.25);
}

.image-tooltip {
    position: absolute; z-index: 200;
    background-color: var(--accent-color); color: #fff; border: none;
    padding: 5px 12px; border-radius: 16px; font-size: 0.82rem;
    cursor: pointer; box-shadow: 0 2px 8px rgba(0,0,0,0.18);
    white-space: nowrap; transition: background-color 0.2s;
    pointer-events: auto;
}
.image-tooltip:hover { background-color: var(--accent-hover); }

.chat-image-preview {
    display: flex; align-items: flex-start; gap: 8px;
    padding: 8px 12px; margin-bottom: 8px;
    background-color: var(--bg-color); border-radius: 10px;
    border: 1px solid var(--border-color); flex-wrap: wrap;
}
.chat-image-preview .ctx-img-thumb {
    height: 48px; width: auto; max-width: 80px;
    border-radius: 6px; object-fit: cover; cursor: pointer;
    border: 2px solid transparent; transition: border-color 0.15s;
}
.chat-image-preview .ctx-img-thumb:hover { border-color: var(--accent-color); }
.chat-image-preview .ctx-text-snippet {
    flex: 1; min-width: 0; font-size: 0.82rem; color: var(--text-muted);
    background: var(--surface-color); border-radius: 6px;
    padding: 6px 10px; position: relative; line-height: 1.4;
    max-height: 52px; overflow: hidden;
}
.chat-image-preview .ctx-text-snippet::before {
    content: '❝'; position: absolute; top: 2px; left: 6px;
    font-size: 0.7rem; color: var(--accent-color); opacity: 0.5;
}
.chat-image-preview .ctx-clear {
    background: none; border: none; color: var(--text-muted);
    font-size: 1rem; padding: 2px 4px; cursor: pointer; flex-shrink: 0;
    line-height: 1; border-radius: 4px;
}
.chat-image-preview .ctx-clear:hover { color: var(--danger-color); background: var(--surface-color); }
.chat-image-preview .ctx-label {
    width: 100%; font-size: 0.78rem; color: var(--text-muted);
    display: flex; align-items: center; justify-content: space-between;
}
.chat-image-preview .ctx-clear-all {
    background: none; border: none; color: var(--text-muted);
    font-size: 0.78rem; cursor: pointer; padding: 2px 6px;
    border-radius: 6px;
}
.chat-image-preview .ctx-clear-all:hover { color: var(--danger-color); }
.markdown-body blockquote {
    border-left: 4px solid var(--accent-color); padding-left: 16px;
    margin: 1.2em 0; color: var(--text-muted);
}
.math-display { text-align: center; margin: 1.5em 0; overflow-x: auto; }
.math-inline { padding: 0 2px; }
.markdown-body .katex-display { margin: 1.5em 0; }

.page-footer { text-align: center; padding: 32px 20px; color: var(--text-muted); font-size: 0.85rem; }

/* ---- 移动端适配 ---- */
@media (max-width: 768px) {
    .markdown-body { padding: 20px 16px; margin: 0; }
    .group-add-form { flex-direction: column; }
    .primary-btn.small { width: 100%; }
    .group-actions { opacity: 1; }
    .selection-tooltip {
        position: fixed !important;
        left: 50% !important;
        top: auto !important;
        bottom: 80px !important;
        transform: translateX(-50%);
    }
    .reader-divider { display: none !important; }
    .reader-chat-pane { display: none !important; }
}

@media (min-width: 769px) {
    .page-header { padding: 40px 20px 24px; }
    .doc-item { padding: 16px 20px; }
}