:root {
    --bg: #efe6d7;
    --bg-soft: #f8f3eb;
    --paper: rgba(255, 250, 244, 0.92);
    --paper-strong: #fffdf9;
    --ink: #241b16;
    --muted: #6e5b4e;
    --line: rgba(36, 27, 22, 0.12);
    --line-strong: rgba(36, 27, 22, 0.2);
    --accent: #a45c40;
    --accent-deep: #6f3622;
    --accent-soft: rgba(164, 92, 64, 0.12);
    --success: #4f6f52;
    --danger: #9f3f34;
    --shadow: 0 24px 70px rgba(78, 51, 33, 0.15);
    --shadow-soft: 0 14px 40px rgba(78, 51, 33, 0.08);
    --radius-xl: 28px;
    --radius-lg: 22px;
    --radius-md: 16px;
    --radius-sm: 12px;
    --font-body: "Avenir Next", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    --font-display: "Iowan Old Style", "Palatino Linotype", "Songti SC", serif;
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    min-height: 100vh;
    color: var(--ink);
    font-family: var(--font-body);
    background:
        radial-gradient(circle at top left, rgba(164, 92, 64, 0.18), transparent 22rem),
        radial-gradient(circle at top right, rgba(79, 111, 82, 0.14), transparent 24rem),
        linear-gradient(180deg, #f7f1e7 0%, #efe6d7 46%, #eadfce 100%);
}

a {
    color: inherit;
    text-decoration: none;
}

button,
input,
select,
textarea {
    font: inherit;
}

button {
    cursor: pointer;
}

code {
    padding: 0.1rem 0.35rem;
    border-radius: 999px;
    background: rgba(36, 27, 22, 0.08);
    font-size: 0.92em;
}

.hidden {
    display: none !important;
}

.app-shell {
    padding-bottom: 4rem;
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 20;
    backdrop-filter: blur(18px);
    background: rgba(247, 241, 231, 0.72);
    border-bottom: 1px solid rgba(36, 27, 22, 0.08);
}

.header-inner,
.page-shell {
    width: min(1280px, calc(100vw - 2rem));
    margin: 0 auto;
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    min-height: 84px;
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 0.9rem;
}

.brand img {
    width: 48px;
    height: 48px;
    border-radius: 16px;
    box-shadow: var(--shadow-soft);
}

.brand strong {
    display: block;
    font-size: 1.15rem;
}

.brand span {
    display: block;
    color: var(--muted);
    font-size: 0.92rem;
}

.top-nav {
    display: inline-flex;
    align-items: center;
    gap: 1rem;
    padding: 0.4rem;
    border-radius: 999px;
    background: rgba(255, 252, 247, 0.66);
    border: 1px solid rgba(36, 27, 22, 0.08);
}

.top-nav a {
    padding: 0.6rem 0.9rem;
    border-radius: 999px;
    color: var(--muted);
    transition: background 180ms ease, color 180ms ease;
}

.top-nav a:hover,
.top-nav a:focus-visible {
    color: var(--accent-deep);
    background: rgba(164, 92, 64, 0.1);
}

.page-shell {
    padding-top: 2rem;
    display: grid;
    gap: 1.8rem;
}

.hero-panel,
.panel {
    border: 1px solid var(--line);
    border-radius: var(--radius-xl);
    background: var(--paper);
    box-shadow: var(--shadow);
}

.hero-panel {
    display: grid;
    grid-template-columns: minmax(0, 1.2fr) minmax(320px, 0.8fr);
    gap: 1.5rem;
    padding: 1.6rem;
    overflow: hidden;
}

.hero-copy {
    padding: 1rem;
}

.hero-copy h1,
.section-heading h2,
.panel-head h3,
.reader-toolbar h3 {
    margin: 0;
    font-family: var(--font-display);
    font-weight: 700;
    line-height: 1.1;
}

.hero-copy h1 {
    margin-top: 0.4rem;
    font-size: clamp(2.2rem, 3.5vw, 4.1rem);
}

.hero-copy p {
    max-width: 52rem;
    line-height: 1.7;
    color: var(--muted);
}

.hero-actions,
.inline-actions,
.backup-actions,
.reader-controls {
    display: flex;
    flex-wrap: wrap;
    gap: 0.8rem;
}

.hero-stats {
    align-self: stretch;
    display: grid;
    gap: 0.9rem;
}

.summary-card {
    padding: 1.15rem 1.2rem;
    border-radius: var(--radius-lg);
    background:
        linear-gradient(180deg, rgba(255, 255, 255, 0.72), rgba(255, 255, 255, 0.5)),
        rgba(164, 92, 64, 0.06);
    border: 1px solid rgba(36, 27, 22, 0.08);
}

.summary-card strong {
    display: block;
    font-size: 2rem;
    margin: 0.2rem 0 0.35rem;
}

.summary-card span,
.summary-card small {
    color: var(--muted);
}

.content-section {
    display: grid;
    gap: 1rem;
}

.section-heading {
    display: flex;
    align-items: end;
    justify-content: space-between;
    gap: 1rem;
}

.section-heading h2 {
    font-size: clamp(1.7rem, 2.4vw, 2.6rem);
}

.section-copy {
    margin: 0;
    max-width: 34rem;
    color: var(--muted);
    line-height: 1.7;
}

.eyebrow {
    margin: 0;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    font-size: 0.78rem;
    color: var(--accent-deep);
}

.library-grid {
    display: grid;
    grid-template-columns: 320px minmax(0, 1fr) 360px;
    gap: 1rem;
    align-items: start;
}

.sidebar-stack,
.content-stack,
.detail-column {
    display: grid;
    gap: 1rem;
}

.panel {
    padding: 1.2rem;
}

.panel-head {
    display: flex;
    align-items: start;
    justify-content: space-between;
    gap: 1rem;
    margin-bottom: 1rem;
}

.panel-head p {
    margin: 0.35rem 0 0;
    color: var(--muted);
    line-height: 1.6;
}

.upload-dropzone {
    width: 100%;
    padding: 2rem 1rem;
    border: 1.5px dashed rgba(164, 92, 64, 0.35);
    border-radius: var(--radius-lg);
    background:
        radial-gradient(circle at top left, rgba(164, 92, 64, 0.14), transparent 14rem),
        linear-gradient(180deg, rgba(255, 250, 244, 0.9), rgba(255, 247, 241, 0.82));
    display: grid;
    place-items: center;
    gap: 0.35rem;
    color: var(--accent-deep);
    text-align: center;
    transition: transform 180ms ease, box-shadow 180ms ease, border-color 180ms ease;
}

.upload-dropzone:hover,
.upload-dropzone:focus-visible,
.upload-dropzone.is-dragover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-soft);
    border-color: rgba(164, 92, 64, 0.75);
}

.dropzone-icon {
    width: 56px;
    height: 56px;
    border-radius: 18px;
    display: inline-grid;
    place-items: center;
    font-size: 2rem;
    color: #fff;
    background: linear-gradient(180deg, var(--accent), var(--accent-deep));
}

.helper-text,
.filter-summary,
.backup-meta {
    margin: 0.8rem 0 0;
    color: var(--muted);
    line-height: 1.6;
}

.field-stack,
.manager-form {
    display: grid;
    gap: 0.9rem;
}

.field {
    display: grid;
    gap: 0.45rem;
}

.field span {
    font-size: 0.95rem;
    color: var(--muted);
}

.field input,
.field select,
.field textarea {
    width: 100%;
    border: 1px solid var(--line-strong);
    border-radius: var(--radius-sm);
    background: var(--paper-strong);
    color: var(--ink);
    padding: 0.85rem 0.95rem;
    transition: border-color 180ms ease, box-shadow 180ms ease;
}

.field input:focus,
.field select:focus,
.field textarea:focus {
    outline: none;
    border-color: rgba(164, 92, 64, 0.72);
    box-shadow: 0 0 0 4px rgba(164, 92, 64, 0.12);
}

.paper-list,
.notes-grid,
.manager-list {
    display: grid;
    gap: 0.8rem;
}

.paper-card,
.note-card,
.manager-item {
    padding: 1rem 1.05rem;
    border-radius: var(--radius-lg);
    background: rgba(255, 252, 247, 0.88);
    border: 1px solid rgba(36, 27, 22, 0.08);
}

.paper-card {
    cursor: pointer;
    transition: transform 180ms ease, box-shadow 180ms ease, border-color 180ms ease;
}

.paper-card:hover,
.paper-card.is-selected {
    transform: translateY(-2px);
    box-shadow: var(--shadow-soft);
    border-color: rgba(164, 92, 64, 0.3);
}

.paper-card-head,
.paper-meta-row,
.manager-item-head,
.note-card-head {
    display: flex;
    justify-content: space-between;
    gap: 0.75rem;
    align-items: start;
}

.paper-card h4,
.manager-item strong,
.note-card h4 {
    margin: 0;
    font-size: 1.02rem;
}

.paper-card p,
.note-card p,
.manager-item p {
    margin: 0.5rem 0 0;
    color: var(--muted);
    line-height: 1.6;
}

.paper-meta-row,
.manager-item-meta {
    margin-top: 0.8rem;
    color: var(--muted);
    font-size: 0.92rem;
}

.tag-row,
.selected-tag-row {
    display: flex;
    flex-wrap: wrap;
    gap: 0.45rem;
    margin-top: 0.85rem;
}

.tag-chip,
.tag-option {
    display: inline-flex;
    align-items: center;
    gap: 0.45rem;
    padding: 0.35rem 0.75rem;
    border-radius: 999px;
    background: rgba(36, 27, 22, 0.06);
    font-size: 0.9rem;
}

.tag-chip-color {
    width: 0.7rem;
    height: 0.7rem;
    border-radius: 999px;
    display: inline-block;
}

.detail-panel {
    position: sticky;
    top: 100px;
}

.paper-detail-empty {
    min-height: 260px;
    display: grid;
    place-items: center;
    text-align: center;
    color: var(--muted);
    line-height: 1.7;
}

.detail-form,
.detail-meta,
.detail-actions {
    display: grid;
    gap: 1rem;
}

.detail-meta {
    padding: 0.95rem 1rem;
    border-radius: var(--radius-md);
    background: rgba(36, 27, 22, 0.04);
    color: var(--muted);
}

.detail-meta strong {
    color: var(--ink);
}

.tag-checklist {
    display: flex;
    flex-wrap: wrap;
    gap: 0.55rem;
}

.tag-option {
    border: 1px solid rgba(36, 27, 22, 0.1);
    background: rgba(255, 255, 255, 0.72);
}

.tag-option input {
    margin: 0;
}

.notes-grid {
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.note-card {
    min-height: 180px;
}

.manager-grid,
.backup-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1rem;
}

.manager-item-actions,
.note-card-actions {
    display: flex;
    gap: 0.6rem;
    margin-top: 0.9rem;
    flex-wrap: wrap;
}

.capability-list {
    margin: 0;
    padding-left: 1.2rem;
    color: var(--muted);
    line-height: 1.8;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.45rem;
    min-height: 44px;
    padding: 0.8rem 1rem;
    border: 0;
    border-radius: 999px;
    transition: transform 180ms ease, box-shadow 180ms ease, opacity 180ms ease, background 180ms ease;
}

.btn:hover,
.btn:focus-visible {
    transform: translateY(-1px);
    box-shadow: var(--shadow-soft);
}

.btn-primary {
    background: linear-gradient(180deg, var(--accent), var(--accent-deep));
    color: #fff;
}

.btn-secondary {
    background: rgba(36, 27, 22, 0.08);
    color: var(--ink);
}

.btn-ghost {
    background: transparent;
    color: var(--muted);
}

.btn-danger {
    background: linear-gradient(180deg, #ba5747, var(--danger));
    color: #fff;
}

.empty-state {
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    text-align: center;
    color: var(--muted);
    background: rgba(255, 252, 247, 0.74);
    border: 1px dashed rgba(36, 27, 22, 0.12);
}

.modal-shell {
    position: fixed;
    inset: 0;
    z-index: 40;
}

.modal-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(24, 16, 12, 0.5);
    backdrop-filter: blur(8px);
}

.modal-dialog {
    position: relative;
    width: min(1320px, calc(100vw - 2rem));
    margin: 2vh auto;
    max-height: 96vh;
    overflow: hidden;
    border-radius: var(--radius-xl);
    background: #f7f1e7;
    box-shadow: 0 30px 90px rgba(19, 10, 5, 0.28);
}

.modal-close {
    position: absolute;
    top: 0.8rem;
    right: 0.8rem;
    z-index: 2;
    width: 42px;
    height: 42px;
    border: 0;
    border-radius: 999px;
    background: rgba(36, 27, 22, 0.08);
    font-size: 1.6rem;
}

.reader-layout {
    display: grid;
    grid-template-columns: minmax(0, 1.45fr) 340px;
    min-height: 82vh;
}

.reader-stage,
.reader-sidebar {
    padding: 1.3rem;
}

.reader-stage {
    display: grid;
    grid-template-rows: auto minmax(0, 1fr);
    gap: 1rem;
    background:
        radial-gradient(circle at top left, rgba(164, 92, 64, 0.12), transparent 18rem),
        rgba(255, 252, 247, 0.88);
}

.reader-sidebar {
    border-left: 1px solid rgba(36, 27, 22, 0.08);
    background: rgba(255, 248, 240, 0.92);
    overflow: auto;
    display: grid;
    align-content: start;
    gap: 1rem;
}

.reader-toolbar {
    display: flex;
    justify-content: space-between;
    gap: 1rem;
    align-items: center;
}

.page-label {
    min-width: 7rem;
    text-align: center;
    color: var(--muted);
}

.reader-canvas-wrap {
    min-height: 0;
    overflow: auto;
    border-radius: var(--radius-lg);
    background: rgba(36, 27, 22, 0.06);
    padding: 1rem;
    display: grid;
    place-items: start center;
}

#readerCanvas {
    width: min(100%, 860px);
    height: auto;
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 20px 40px rgba(36, 27, 22, 0.15);
}

.reader-meta {
    display: grid;
    gap: 0.7rem;
    padding: 1rem;
    border-radius: var(--radius-md);
    background: rgba(255, 255, 255, 0.66);
    border: 1px solid rgba(36, 27, 22, 0.08);
    color: var(--muted);
}

.reader-meta strong {
    color: var(--ink);
}

.busy-overlay {
    position: fixed;
    inset: 0;
    z-index: 50;
    display: grid;
    place-items: center;
    background: rgba(18, 11, 8, 0.35);
    backdrop-filter: blur(8px);
}

.busy-card {
    min-width: 220px;
    padding: 1.4rem 1.5rem;
    border-radius: var(--radius-lg);
    background: rgba(255, 252, 247, 0.92);
    box-shadow: var(--shadow);
    display: grid;
    place-items: center;
    gap: 0.8rem;
}

.spinner {
    width: 38px;
    height: 38px;
    border-radius: 999px;
    border: 3px solid rgba(164, 92, 64, 0.18);
    border-top-color: var(--accent);
    animation: spin 900ms linear infinite;
}

.toast-region {
    position: fixed;
    right: 1rem;
    bottom: 1rem;
    z-index: 60;
    display: grid;
    gap: 0.7rem;
}

.toast {
    min-width: 240px;
    max-width: 360px;
    padding: 0.9rem 1rem;
    border-radius: var(--radius-md);
    color: #fff;
    box-shadow: var(--shadow-soft);
}

.toast-info {
    background: linear-gradient(180deg, #416788, #2f4b63);
}

.toast-success {
    background: linear-gradient(180deg, #658e69, var(--success));
}

.toast-error {
    background: linear-gradient(180deg, #bf6355, var(--danger));
}

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

@media (max-width: 1120px) {
    .library-grid {
        grid-template-columns: 1fr;
    }

    .detail-panel {
        position: static;
    }

    .reader-layout {
        grid-template-columns: 1fr;
    }

    .reader-sidebar {
        border-left: 0;
        border-top: 1px solid rgba(36, 27, 22, 0.08);
    }
}

@media (max-width: 920px) {
    .header-inner {
        flex-wrap: wrap;
        padding: 0.75rem 0;
    }

    .top-nav {
        order: 3;
        width: 100%;
        justify-content: center;
        flex-wrap: wrap;
    }

    .hero-panel,
    .manager-grid,
    .backup-grid {
        grid-template-columns: 1fr;
    }

    .section-heading {
        align-items: start;
        flex-direction: column;
    }
}

@media (max-width: 640px) {
    .header-inner,
    .page-shell {
        width: min(100vw - 1rem, 100%);
    }

    .hero-panel,
    .panel,
    .modal-dialog {
        border-radius: 22px;
    }

    .hero-copy,
    .reader-stage,
    .reader-sidebar {
        padding: 1rem;
    }

    .hero-copy h1 {
        font-size: 2rem;
    }

    .reader-toolbar,
    .paper-card-head,
    .paper-meta-row,
    .manager-item-head,
    .note-card-head {
        flex-direction: column;
    }
}