* {
    box-sizing: border-box;
}

html, body {
    margin: 0;
    padding: 0;
    height: 100%;
}

/* =============================
   主题变量（默认深色）
   ============================= */
:root {
    --app-max-width: 960px;
    --reader-max-width: 1200px;

    --radius: 14px;
    --border: rgba(255, 255, 255, 0.10);
    --border-soft: rgba(255, 255, 255, 0.07);
    --shadow: 0 10px 28px rgba(0, 0, 0, 0.40);

    --page-bg: #0a0a0a;
    --shell-bg: #101010;
    --panel-bg: rgba(18, 18, 18, 0.78);
    --panel-bg-strong: rgba(18, 18, 18, 0.92);
    --card-bg: rgba(255, 255, 255, 0.05);

    --text: rgba(255, 255, 255, 0.92);
    --muted: rgba(255, 255, 255, 0.68);
    --muted2: rgba(255, 255, 255, 0.48);

    --accent: #3b82f6;
    --danger: #ef4444;

    /* 默认阅读样式变量，可被 JS 调整 */
    --reader-font-size: 17px;
    --reader-line-height: 1.8;
    --reader-padding-v: 14px;
    --reader-padding-h: 16px;
}

:root[data-theme="paper"] {
    --page-bg: #f4f3ef;
    --shell-bg: #ffffff;
    --panel-bg: rgba(255, 255, 255, 0.80);
    --panel-bg-strong: rgba(255, 255, 255, 0.94);
    --card-bg: rgba(17, 24, 39, 0.05);

    --text: rgba(17, 24, 39, 0.95);
    --muted: rgba(17, 24, 39, 0.70);
    --muted2: rgba(17, 24, 39, 0.52);

    --border: rgba(17, 24, 39, 0.14);
    --border-soft: rgba(17, 24, 39, 0.10);
}

:root[data-theme="sepia"] {
    --page-bg: #16130f;
    --shell-bg: #14110d;
    --panel-bg: rgba(22, 19, 15, 0.80);
    --panel-bg-strong: rgba(22, 19, 15, 0.94);
    --card-bg: rgba(255, 244, 226, 0.06);

    --text: rgba(255, 244, 226, 0.93);
    --muted: rgba(255, 244, 226, 0.70);
    --muted2: rgba(255, 244, 226, 0.52);

    --border: rgba(255, 244, 226, 0.14);
    --border-soft: rgba(255, 244, 226, 0.10);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", system-ui, "PingFang SC", "Helvetica Neue", Arial, sans-serif;
    background: var(--page-bg);
    color: var(--text);
}

/* =============================
   通用 App 外壳
   ============================= */
.app-shell {
    max-width: var(--app-max-width);
    margin: 0 auto;
    min-height: 100%;
    display: flex;
    flex-direction: column;
    background: var(--shell-bg);
}

/* 书库页面整体 */
.bookshelf-page .app-shell {
    background: var(--shell-bg);
}

/* 顶部导航（书库） */
.app-header {
    height: 52px;
    padding: 0 12px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: var(--panel-bg-strong);
    border-bottom: 1px solid var(--border-soft);
}

.app-title {
    font-size: 18px;
    font-weight: 650;
    letter-spacing: 0.2px;
}

.app-header-right {
    font-size: 14px;
}

.header-link,
.header-back {
    color: var(--accent);
    text-decoration: none;
    font-size: 14px;
}

/* 书库内容区域 */
.app-content {
    padding: 12px;
    flex: 1;
    overflow-y: auto;
}

/* 提示卡片 */
.hint-card {
    background: var(--card-bg);
    border: 1px solid var(--border-soft);
    border-radius: var(--radius);
    padding: 10px 12px;
    font-size: 14px;
    margin-bottom: 12px;
    color: var(--muted);
}

/* 书库列表 */
.book-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.book-card {
    background: var(--card-bg);
    border: 1px solid var(--border-soft);
    border-radius: var(--radius);
    padding: 12px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 10px;
}

.book-title {
    font-size: 16px;
    font-weight: 650;
    margin-bottom: 4px;
}

.book-meta {
    font-size: 12px;
    color: var(--muted2);
}

.book-actions {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

/* =============================
   按钮（通用）
   ============================= */
.btn {
    border: 1px solid var(--border-soft);
    border-radius: 999px;
    padding: 7px 12px;
    font-size: 13px;
    cursor: pointer;
    text-decoration: none;
    display: inline-block;
    text-align: center;
    background: rgba(255, 255, 255, 0.06);
    color: var(--text);
    user-select: none;
    -webkit-tap-highlight-color: transparent;
}

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

.btn.primary {
    background: var(--accent);
    border-color: rgba(59, 130, 246, 0.55);
    color: #fff;
}

.btn.danger {
    background: var(--danger);
    border-color: rgba(239, 68, 68, 0.55);
    color: #fff;
}

.btn.secondary {
    background: rgba(255, 255, 255, 0.06);
}

.btn.tiny {
    padding: 4px 10px;
    font-size: 12px;
}

/* 小屏适配书库卡片 */
@media (max-width: 600px) {
    .book-card {
        flex-direction: column;
        align-items: flex-start;
    }
    .book-actions {
        flex-direction: row;
        flex-wrap: wrap;
    }
}

/* =============================
   阅读器
   ============================= */
.reader-page {
    overflow: hidden;
}

/* 阅读器页面使用更宽的壳 */
.reader-page .app-shell {
    max-width: var(--reader-max-width);
}

.reader-shell {
    position: relative;
    height: 100dvh;
    overflow: hidden;

    /* 上下栏高度（不含安全区） */
    --header-bar-h: 52px;
    --footer-bar-h: 64px;

    /* 实际占用：含安全区 */
    --chrome-top: calc(var(--header-bar-h) + env(safe-area-inset-top));
    --chrome-bottom: calc(var(--footer-bar-h) + env(safe-area-inset-bottom));
}

/* 沉浸模式：只保留安全区占用，让内容尽可能顶满 */
.reader-shell.chrome-hidden {
    --chrome-top: env(safe-area-inset-top);
    --chrome-bottom: env(safe-area-inset-bottom);
}

/* 阅读器头部（固定叠层） */
.reader-header {
    position: fixed;
    top: 0;
    left: 50%;
    width: min(var(--reader-max-width), 100%);
    height: calc(var(--header-bar-h) + env(safe-area-inset-top));
    padding: 0 calc(12px + env(safe-area-inset-right)) 0 calc(12px + env(safe-area-inset-left));
    padding-top: env(safe-area-inset-top);

    display: flex;
    align-items: center;
    justify-content: space-between;

    background: var(--panel-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);

    border-bottom: 1px solid var(--border-soft);

    transform: translateX(-50%) translateY(0);
    transition: transform 0.25s ease, opacity 0.25s ease;
    z-index: 60;
}

.reader-title {
    flex: 1;
    text-align: center;
    padding: 0 10px;
    font-size: 15px;
    font-weight: 600;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.header-btn {
    white-space: nowrap;
}

/* 阅读器主区域：内部不滚动 */
.reader-main {
    flex: 1;
    position: relative;
    overflow: hidden;

    padding-top: calc(var(--reader-padding-v) + var(--chrome-top));
    padding-bottom: calc(var(--reader-padding-v) + var(--chrome-bottom));
    padding-left: calc(var(--reader-padding-h) + env(safe-area-inset-left));
    padding-right: calc(var(--reader-padding-h) + env(safe-area-inset-right));
}

/* 内层用于动画 */
.reader-main-inner {
    height: 100%;
    display: flex;
    flex-direction: column;
    transition: transform 0.25s ease, opacity 0.25s ease;
}

/* 章节标题 */
.chapter-title {
    font-size: 20px;
    font-weight: 700;
    letter-spacing: 0.2px;
    margin: 0 0 10px;
}

/* 分页展示区域 */
.chapter-content {
    flex: 1;
    overflow: hidden;
    font-size: var(--reader-font-size);
    line-height: var(--reader-line-height);
    color: var(--text);
    letter-spacing: 0.2px;
    text-rendering: optimizeLegibility;
}

.page-inner {
    height: 100%;
    padding-bottom: 2px; /* 防止极少数浏览器出现最后一行裁切 */
}

.page-inner p {
    margin: 0 0 0.85em;
}

/* 右下角常驻阅读进度 */
.reading-progress {
    position: absolute;
    right: 10px;
    bottom: 10px;
    font-size: 11px;
    color: var(--muted);
    background: var(--panel-bg-strong);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--border-soft);
    padding: 4px 10px;
    border-radius: 999px;
    pointer-events: none;
}

/* 底部栏（固定叠层） */
.reader-footer {
    position: fixed;
    bottom: 0;
    left: 50%;
    width: min(var(--reader-max-width), 100%);
    height: calc(var(--footer-bar-h) + env(safe-area-inset-bottom));

    padding: 10px calc(10px + env(safe-area-inset-right)) env(safe-area-inset-bottom) calc(10px + env(safe-area-inset-left));

    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 10px;

    background: var(--panel-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);

    border-top: 1px solid var(--border-soft);

    transform: translateX(-50%) translateY(0);
    transition: transform 0.25s ease, opacity 0.25s ease;
    z-index: 60;
}

.nav-btn {
    min-width: 88px;
}

.reader-footer-middle {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
    min-width: 0;
}

.footer-progress {
    font-size: 12px;
    color: var(--muted);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.footer-actions {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    justify-content: center;
}

/* 隐藏 UI 时的样式：上下栏滑走（并且 main 会因为变量变化释放空间） */
.reader-shell.chrome-hidden .reader-header {
    transform: translateX(-50%) translateY(-110%);
    opacity: 0;
    pointer-events: none;
}

.reader-shell.chrome-hidden .reader-footer {
    transform: translateX(-50%) translateY(110%);
    opacity: 0;
    pointer-events: none;
}

/* 小屏优化 */
@media (max-width: 600px) {
    .nav-btn {
        min-width: 76px;
        padding-left: 10px;
        padding-right: 10px;
    }
    .footer-progress {
        font-size: 11px;
    }
}

/* =============================
   通用弹窗（设置 / AI）
   ============================= */
.modal {
    position: fixed;
    inset: 0;
    z-index: 90;
    display: none;
}

.modal.show {
    display: block;
}

.modal-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0.55);
}

.modal-panel {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    width: min(720px, calc(100% - 20px));
    max-height: calc(100% - 20px);

    background: var(--shell-bg);
    border: 1px solid var(--border);
    border-radius: calc(var(--radius) + 4px);
    box-shadow: var(--shadow);

    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.modal-header {
    padding: 10px 12px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
    background: var(--panel-bg-strong);
    border-bottom: 1px solid var(--border-soft);
}

.modal-title {
    font-size: 14px;
    font-weight: 650;
    color: var(--text);
}

.modal-body {
    padding: 12px;
    overflow: auto;
    -webkit-overflow-scrolling: touch;
}

/* 小屏：改成底部弹出更顺手 */
@media (max-width: 600px) {
    .modal-panel {
        top: auto;
        bottom: 10px;
        transform: translateX(-50%);
        width: calc(100% - 16px);
        max-height: calc(100% - 16px);
        border-radius: 18px;
    }
}

/* =============================
   设置弹窗
   ============================= */
.setting-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
    padding: 10px 0;
    border-bottom: 1px dashed var(--border-soft);
}

.setting-row:last-child {
    border-bottom: none;
}

.setting-label {
    font-size: 13px;
    color: var(--muted);
    white-space: nowrap;
}

.setting-controls {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
    justify-content: flex-end;
}

.setting-controls input {
    width: 120px;
    max-width: 42vw;
    padding: 8px 10px;
    border-radius: 12px;
    border: 1px solid var(--border-soft);
    background: rgba(255, 255, 255, 0.06);
    color: var(--text);
    outline: none;
}

.setting-controls input:focus {
    border-color: rgba(59, 130, 246, 0.55);
}

.setting-hint {
    margin-top: 12px;
    padding: 10px 12px;
    border: 1px solid var(--border-soft);
    border-radius: var(--radius);
    background: var(--card-bg);
    color: var(--muted);
    font-size: 12px;
}

.setting-hint ul {
    margin: 8px 0 0;
    padding-left: 18px;
}

.setting-hint li {
    margin: 6px 0;
}

/* =============================
   选中浮条
   ============================= */
.selection-actions {
    position: fixed;
    z-index: 80;
    display: none;
    gap: 8px;
    padding: 6px;

    background: var(--panel-bg-strong);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);

    border: 1px solid var(--border);
    border-radius: 999px;
    box-shadow: var(--shadow);

    transform: translateX(-50%);
}

.selection-actions.show {
    display: flex;
}

/* =============================
   AI 弹窗
   ============================= */
.modal-ai .modal-panel {
    width: min(920px, calc(100% - 20px));
}

.ai-body {
    display: flex;
    flex-direction: column;
    gap: 10px;
    overflow: hidden;
}

.ai-context {
    border: 1px solid var(--border-soft);
    border-radius: var(--radius);
    background: var(--card-bg);
    padding: 10px 12px;
}

.ai-context-label {
    font-size: 12px;
    color: var(--muted);
    margin-bottom: 8px;
}

.ai-context-preview {
    max-height: 140px;
    overflow: auto;
    -webkit-overflow-scrolling: touch;
    font-size: 13px;
    line-height: 1.6;
    color: var(--text);
    white-space: pre-wrap;
}

.ai-quick {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

.ai-chat-log {
    flex: 1;
    overflow: auto;
    -webkit-overflow-scrolling: touch;

    border: 1px solid var(--border-soft);
    border-radius: var(--radius);
    background: var(--card-bg);
    padding: 10px 10px;
}

.ai-msg {
    display: flex;
    margin: 8px 0;
}

.ai-msg.user {
    justify-content: flex-end;
}

.ai-msg.assistant {
    justify-content: flex-start;
}

.ai-bubble {
    max-width: 92%;
    padding: 9px 10px;
    border-radius: 14px;
    border: 1px solid var(--border-soft);
    white-space: pre-wrap;
    word-break: break-word;
}

.ai-msg.user .ai-bubble {
    background: rgba(59, 130, 246, 0.15);
    border-color: rgba(59, 130, 246, 0.35);
}

.ai-msg.assistant .ai-bubble {
    background: rgba(255, 255, 255, 0.04);
}

.ai-input {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.ai-input textarea {
    width: 100%;
    resize: none;
    padding: 10px 12px;
    border-radius: var(--radius);
    border: 1px solid var(--border-soft);
    background: rgba(255, 255, 255, 0.06);
    color: var(--text);
    outline: none;
}

.ai-input textarea:focus {
    border-color: rgba(59, 130, 246, 0.55);
}

.ai-actions {
    display: flex;
    gap: 10px;
    justify-content: flex-end;
}

.ai-error {
    margin-top: 2px;
    padding: 8px 10px;
    border-radius: var(--radius);
    border: 1px solid rgba(239, 68, 68, 0.35);
    background: rgba(239, 68, 68, 0.10);
    color: var(--text);
    font-size: 12px;
}

/* =============================
   Toast
   ============================= */
.toast {
    position: fixed;
    left: 50%;
    bottom: 22px;
    transform: translateX(-50%);
    z-index: 120;

    background: var(--panel-bg-strong);
    border: 1px solid var(--border-soft);
    border-radius: 999px;
    box-shadow: var(--shadow);

    padding: 8px 12px;
    font-size: 12px;
    color: var(--text);

    opacity: 0;
    pointer-events: none;
    transition: opacity 0.2s ease;
}

.toast.show {
    opacity: 1;
}