diff --git a/.streamlit/config.toml b/.streamlit/config.toml
index fa008c6..554fbcb 100644
--- a/.streamlit/config.toml
+++ b/.streamlit/config.toml
@@ -9,3 +9,17 @@ gatherUsageStats = false
 # reads "Limit 1024MB per file" — matches the analyzer + gate's stated
 # 1 GB efficiency target. See docs/REQUIREMENTS.md §1.1.
 maxUploadSize = 1024
+
+# Warm, editorial palette inspired by the
+# ``datatools_layout_redesign.html`` mockup — cream paper background,
+# stone ink, burnt-orange accent. Streamlit reads these on startup and
+# threads them through its widget chrome (file uploader, focus rings,
+# primary buttons, links). Heavier visual restyling rides on the CSS
+# in ``_legacy.py:_DESIGN_TOKENS_CSS``.
+[theme]
+base = "light"
+primaryColor = "#c2410c"
+backgroundColor = "#fafaf7"
+secondaryBackgroundColor = "#f5f4ef"
+textColor = "#1c1917"
+font = "sans serif"
diff --git a/src/gui/components/_legacy.py b/src/gui/components/_legacy.py
index 3aed7ec..93323cb 100644
--- a/src/gui/components/_legacy.py
+++ b/src/gui/components/_legacy.py
@@ -137,6 +137,319 @@ hr { margin-top: 0.4rem !important; margin-bottom: 0.4rem !important; }
 """
 
 
+# Warm editorial palette + typography, lifted from the
+# ``datatools_layout_redesign.html`` mockup. Applied on every page via
+# ``hide_streamlit_chrome``. Tokens are scoped through CSS custom
+# properties so individual rules read cleanly and a future tweak only
+# has to touch the ``:root`` block.
+_DESIGN_TOKENS_CSS = """
+<style>
+@import url('https://fonts.googleapis.com/css2?family=Fraunces:opsz,wght@9..144,400;9..144,500;9..144,600&family=Geist:wght@400;500;600&family=Geist+Mono:wght@400;500&display=swap');
+
+:root {
+    --dt-bg:              #fafaf7;
+    --dt-bg-sidebar:      #f5f4ef;
+    --dt-surface:         #ffffff;
+    --dt-surface-hover:   #f8f7f3;
+    --dt-border:          #e7e5dc;
+    --dt-border-strong:   #d6d3c7;
+    --dt-ink:             #1c1917;
+    --dt-ink-secondary:   #57534e;
+    --dt-ink-tertiary:    #a8a29e;
+    --dt-accent:          #c2410c;
+    --dt-accent-hover:    #9a3412;
+    --dt-accent-fill:     #fef4ed;
+    --dt-warn:            #b45309;
+    --dt-warn-fill:       #fef3c7;
+    --dt-info:            #0369a1;
+    --dt-info-fill:       #e0f2fe;
+    --dt-success:         #15803d;
+    --dt-success-fill:    #dcfce7;
+    --dt-danger:          #b91c1c;
+    --dt-danger-fill:     #fee2e2;
+    --dt-r-sm: 6px;
+    --dt-r-md: 10px;
+    --dt-r-lg: 14px;
+    --dt-font-display:    "Fraunces", Georgia, serif;
+    --dt-font-body:       "Geist", -apple-system, BlinkMacSystemFont, sans-serif;
+    --dt-font-mono:       "Geist Mono", "SF Mono", Menlo, monospace;
+}
+
+/* ---------- Page surface ---------- */
+body, .stApp {
+    background: var(--dt-bg) !important;
+    font-family: var(--dt-font-body) !important;
+    color: var(--dt-ink) !important;
+    -webkit-font-smoothing: antialiased;
+}
+
+/* ---------- Sidebar — cream paper, soft right edge ---------- */
+[data-testid="stSidebar"] {
+    background: var(--dt-bg-sidebar) !important;
+    border-right: 1px solid var(--dt-border) !important;
+}
+[data-testid="stSidebar"] > div:first-child {
+    background: var(--dt-bg-sidebar) !important;
+}
+
+/* Section labels in the page-nav: tiny uppercase tracking. Streamlit
+   renders these as <span> nodes with class ``st-emotion-cache-…``
+   inside ``stSidebarNav`` — class hashes are unstable across versions,
+   so we lean on the structural position (the bare span/h2 directly
+   inside the nav list) rather than emotion classes. */
+[data-testid="stSidebarNav"] h2,
+[data-testid="stSidebarNav"] h3,
+[data-testid="stSidebarNavSeparator"] span,
+[data-testid="stSidebarNavSectionHeader"] {
+    font-family: var(--dt-font-body) !important;
+    font-size: 10.5px !important;
+    text-transform: uppercase !important;
+    letter-spacing: 0.08em !important;
+    color: var(--dt-ink-tertiary) !important;
+    font-weight: 500 !important;
+    padding-top: 14px !important;
+    padding-bottom: 4px !important;
+    margin: 0 !important;
+}
+
+/* Nav items: comfortable padding, soft hover. */
+[data-testid="stSidebarNav"] a[data-testid="stSidebarNavLink"],
+[data-testid="stSidebarNav"] [data-testid="stSidebarNavLinkContainer"] a {
+    color: var(--dt-ink-secondary) !important;
+    font-size: 13.5px !important;
+    line-height: 1.3 !important;
+    padding: 7px 10px !important;
+    border-radius: var(--dt-r-sm) !important;
+    transition: background 0.12s ease, color 0.12s ease;
+}
+[data-testid="stSidebarNav"] a[data-testid="stSidebarNavLink"]:hover,
+[data-testid="stSidebarNav"] [data-testid="stSidebarNavLinkContainer"] a:hover {
+    background: rgba(0,0,0,0.04) !important;
+    color: var(--dt-ink) !important;
+}
+/* Active nav item — white pill with subtle shadow. Streamlit marks the
+   active anchor with ``aria-current="page"``. */
+[data-testid="stSidebarNav"] a[aria-current="page"] {
+    background: var(--dt-surface) !important;
+    color: var(--dt-ink) !important;
+    font-weight: 500 !important;
+    box-shadow: 0 1px 2px rgba(28,25,23,0.04) !important;
+}
+
+/* ---------- Typography ---------- */
+.stApp h1, [data-testid="stMain"] h1 {
+    font-family: var(--dt-font-display) !important;
+    font-weight: 500 !important;
+    font-size: 32px !important;
+    letter-spacing: -0.025em !important;
+    line-height: 1.1 !important;
+    color: var(--dt-ink) !important;
+}
+.stApp h2, [data-testid="stMain"] h2 {
+    font-family: var(--dt-font-display) !important;
+    font-weight: 500 !important;
+    font-size: 22px !important;
+    letter-spacing: -0.02em !important;
+    color: var(--dt-ink) !important;
+}
+.stApp h3, [data-testid="stMain"] h3 {
+    font-family: var(--dt-font-display) !important;
+    font-weight: 500 !important;
+    font-size: 18px !important;
+    letter-spacing: -0.015em !important;
+    color: var(--dt-ink) !important;
+}
+/* st.caption + subheadings are body-sans, secondary ink. */
+[data-testid="stCaption"],
+[data-testid="stCaptionContainer"] {
+    color: var(--dt-ink-secondary) !important;
+    font-size: 13.5px !important;
+}
+/* Inline + block code in user-facing text → Geist Mono. */
+[data-testid="stMarkdownContainer"] code,
+[data-testid="stCode"] pre {
+    font-family: var(--dt-font-mono) !important;
+    background: var(--dt-accent-fill) !important;
+    color: var(--dt-accent-hover) !important;
+    padding: 1px 5px !important;
+    border-radius: 4px !important;
+    font-size: 0.92em !important;
+}
+[data-testid="stCode"] pre {
+    padding: 12px 14px !important;
+    background: var(--dt-surface-hover) !important;
+    color: var(--dt-ink) !important;
+    border: 1px solid var(--dt-border) !important;
+    border-radius: var(--dt-r-md) !important;
+}
+
+/* ---------- Buttons — ink primary, outlined secondary ---------- */
+[data-testid="stButton"] button,
+[data-testid="stDownloadButton"] button {
+    border-radius: var(--dt-r-md) !important;
+    font-family: var(--dt-font-body) !important;
+    font-weight: 500 !important;
+    font-size: 13.5px !important;
+    line-height: 1 !important;
+    padding: 9px 16px !important;
+    transition: background 0.12s ease, border-color 0.12s ease, color 0.12s ease;
+}
+/* Primary = dark ink (matches mockup's ``btn-primary``). */
+[data-testid="stButton"] button[kind="primary"],
+[data-testid="stButton"] button[data-testid="stBaseButton-primary"],
+[data-testid="stDownloadButton"] button[kind="primary"] {
+    background: var(--dt-ink) !important;
+    color: var(--dt-bg) !important;
+    border: 1px solid var(--dt-ink) !important;
+}
+[data-testid="stButton"] button[kind="primary"]:hover,
+[data-testid="stButton"] button[data-testid="stBaseButton-primary"]:hover,
+[data-testid="stDownloadButton"] button[kind="primary"]:hover {
+    background: #292524 !important;
+    border-color: #292524 !important;
+    color: var(--dt-bg) !important;
+}
+/* Secondary = surface + warm border. */
+[data-testid="stButton"] button[kind="secondary"],
+[data-testid="stButton"] button[data-testid="stBaseButton-secondary"],
+[data-testid="stDownloadButton"] button[kind="secondary"] {
+    background: var(--dt-surface) !important;
+    color: var(--dt-ink) !important;
+    border: 1px solid var(--dt-border-strong) !important;
+}
+[data-testid="stButton"] button[kind="secondary"]:hover,
+[data-testid="stButton"] button[data-testid="stBaseButton-secondary"]:hover {
+    background: var(--dt-surface-hover) !important;
+    border-color: var(--dt-ink-tertiary) !important;
+}
+/* Disabled state — same look both kinds, low-contrast. */
+[data-testid="stButton"] button:disabled {
+    background: var(--dt-surface-hover) !important;
+    color: var(--dt-ink-tertiary) !important;
+    border-color: var(--dt-border) !important;
+    cursor: not-allowed !important;
+}
+
+/* ---------- File uploader — soft cream dropzone ---------- */
+[data-testid="stFileUploader"] section,
+[data-testid="stFileUploaderDropzone"] {
+    background: var(--dt-surface-hover) !important;
+    border: 1px dashed var(--dt-border-strong) !important;
+    border-radius: var(--dt-r-md) !important;
+}
+[data-testid="stFileUploader"] button {
+    border-radius: var(--dt-r-md) !important;
+}
+/* The per-file chip rows the uploader emits after a file is staged. */
+[data-testid="stFileUploaderFile"] {
+    background: var(--dt-surface) !important;
+    border: 1px solid var(--dt-border) !important;
+    border-radius: var(--dt-r-sm) !important;
+}
+
+/* ---------- Expanders + bordered containers → editorial cards ---------- */
+[data-testid="stExpander"] details,
+[data-testid="stExpander"] {
+    background: var(--dt-surface) !important;
+    border: 1px solid var(--dt-border) !important;
+    border-radius: var(--dt-r-lg) !important;
+    overflow: hidden !important;
+    box-shadow: 0 1px 2px rgba(28,25,23,0.03);
+}
+[data-testid="stExpander"] details > summary {
+    background: var(--dt-surface-hover) !important;
+    border-bottom: 1px solid var(--dt-border) !important;
+    padding: 12px 16px !important;
+    font-weight: 500 !important;
+    color: var(--dt-ink) !important;
+}
+[data-testid="stExpander"] details[open] > summary {
+    border-bottom: 1px solid var(--dt-border) !important;
+}
+[data-testid="stExpander"] details > div {
+    padding: 14px 16px !important;
+}
+
+/* ``st.container(border=True)`` — same card treatment. */
+[data-testid="stVerticalBlockBorderWrapper"],
+div[data-testid="stContainer"][data-border="true"] {
+    background: var(--dt-surface) !important;
+    border: 1px solid var(--dt-border) !important;
+    border-radius: var(--dt-r-lg) !important;
+    box-shadow: 0 1px 2px rgba(28,25,23,0.03);
+}
+
+/* ---------- Alerts — soft fills, no harsh borders ---------- */
+[data-testid="stAlert"] [data-testid="stAlertContainer"],
+[data-testid="stAlertContainer"] {
+    border-radius: var(--dt-r-md) !important;
+    border: 1px solid transparent !important;
+    padding: 10px 14px !important;
+    font-size: 13.5px !important;
+}
+/* Streamlit tags each alert kind on the wrapper; target both the
+   legacy class hooks and the newer per-kind ``data-baseweb-color``. */
+[data-testid="stAlertContainer"][kind="info"],
+.stAlert[data-baseweb="notification"][kind="info"] {
+    background: var(--dt-info-fill) !important;
+    color: var(--dt-info) !important;
+}
+[data-testid="stAlertContainer"][kind="success"],
+.stAlert[data-baseweb="notification"][kind="success"] {
+    background: var(--dt-success-fill) !important;
+    color: var(--dt-success) !important;
+}
+[data-testid="stAlertContainer"][kind="warning"],
+.stAlert[data-baseweb="notification"][kind="warning"] {
+    background: var(--dt-warn-fill) !important;
+    color: var(--dt-warn) !important;
+}
+[data-testid="stAlertContainer"][kind="error"],
+.stAlert[data-baseweb="notification"][kind="error"] {
+    background: var(--dt-danger-fill) !important;
+    color: var(--dt-danger) !important;
+}
+
+/* ---------- Inputs (text, select, multiselect) — paper surface ---------- */
+[data-testid="stTextInput"] input,
+[data-testid="stTextArea"] textarea,
+[data-testid="stNumberInput"] input,
+[data-testid="stSelectbox"] div[role="combobox"],
+[data-testid="stMultiSelect"] div[role="combobox"],
+[data-baseweb="select"] > div {
+    background: var(--dt-surface) !important;
+    border-radius: var(--dt-r-sm) !important;
+    border-color: var(--dt-border-strong) !important;
+    font-family: var(--dt-font-body) !important;
+}
+
+/* Divider — softer warm gray instead of cool Streamlit default. */
+[data-testid="stMarkdownContainer"] hr,
+.stApp hr {
+    border-color: var(--dt-border) !important;
+}
+
+/* Tabs — pill-style with active underline in accent. */
+[data-testid="stTabs"] [role="tab"] {
+    font-family: var(--dt-font-body) !important;
+    font-size: 13.5px !important;
+    color: var(--dt-ink-secondary) !important;
+}
+[data-testid="stTabs"] [role="tab"][aria-selected="true"] {
+    color: var(--dt-ink) !important;
+    font-weight: 500 !important;
+}
+
+/* DataFrame surface — warm card, mono cells. */
+[data-testid="stDataFrame"] {
+    border-radius: var(--dt-r-md) !important;
+    border: 1px solid var(--dt-border) !important;
+    overflow: hidden !important;
+}
+</style>
+"""
+
+
 def hide_streamlit_chrome(*, gate_license: bool = True) -> None:
     """Inject CSS to hide Streamlit's default header, menu, and footer.
 
@@ -154,6 +467,7 @@ def hide_streamlit_chrome(*, gate_license: bool = True) -> None:
     can render its own form without recursion.
     """
     st.markdown(_HIDE_CHROME_CSS, unsafe_allow_html=True)
+    st.markdown(_DESIGN_TOKENS_CSS, unsafe_allow_html=True)
     # Stamp a session-start record into the audit log the first time
     # any page renders. Idempotent — subsequent calls are no-ops.
     # Wrapped because a broken audit log MUST NOT take the GUI down.