diff --git a/.streamlit/config.toml b/.streamlit/config.toml
new file mode 100644
index 0000000..82b5671
--- /dev/null
+++ b/.streamlit/config.toml
@@ -0,0 +1,6 @@
+[theme]
+primaryColor = "#1E5BA8"
+backgroundColor = "#F4F7FA"
+secondaryBackgroundColor = "#E8EDF3"
+textColor = "#0F1419"
+font = "sans serif"
diff --git a/assets/bouncing_penguin.png b/assets/bouncing_penguin.png
new file mode 100644
index 0000000..99d5b9a
Binary files /dev/null and b/assets/bouncing_penguin.png differ
diff --git a/assets/sipa_logo.png b/assets/sipa_logo.png
new file mode 100644
index 0000000..64bd161
Binary files /dev/null and b/assets/sipa_logo.png differ
diff --git a/assets/style.css b/assets/style.css
new file mode 100644
index 0000000..0657247
--- /dev/null
+++ b/assets/style.css
@@ -0,0 +1,276 @@
+/* ===== Bouncing Penguin · Columbia SIPA — Dashboard Styles ===== */
+
+@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;500;600;700&family=Inter:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500;600;700&display=swap');
+
+/* ----- Global typography ----- */
+html, body, [class*="css"], .stApp, .main, [data-testid="stAppViewContainer"] {
+    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif !important;
+    color: #0F1419;
+}
+
+h1, h2, h3, h4, h5, h6,
+[data-testid="stHeader"] h1,
+.stMarkdown h1, .stMarkdown h2, .stMarkdown h3, .stMarkdown h4 {
+    font-family: 'Space Grotesk', 'Inter', sans-serif !important;
+    font-weight: 600 !important;
+    color: #1F3464 !important;
+    letter-spacing: -0.01em;
+}
+
+code, pre, kbd, samp,
+[data-testid="stCodeBlock"], .stCodeBlock {
+    font-family: 'JetBrains Mono', 'Menlo', monospace !important;
+}
+
+/* ----- Page title (h1) accent ----- */
+.stApp h1:first-of-type {
+    border-bottom: 3px solid #1E5BA8;
+    padding-bottom: 8px;
+    display: inline-block;
+    margin-bottom: 8px;
+}
+
+/* ----- Section headings (h2) — blue dot bullet ----- */
+.stMarkdown h2,
+.stApp [data-testid="stMarkdownContainer"] h2,
+[data-testid="stHeading"] h2 {
+    position: relative;
+    padding-left: 18px;
+}
+.stMarkdown h2::before,
+[data-testid="stMarkdownContainer"] h2::before,
+[data-testid="stHeading"] h2::before {
+    content: "";
+    position: absolute;
+    left: 0;
+    top: 50%;
+    transform: translateY(-50%);
+    width: 8px;
+    height: 8px;
+    border-radius: 50%;
+    background: #1E5BA8;
+    box-shadow: 0 0 0 3px rgba(30, 91, 168, 0.15);
+}
+
+/* ----- Subheaders (h3) — softer accent ----- */
+.stMarkdown h3,
+[data-testid="stMarkdownContainer"] h3 {
+    color: #1F3464 !important;
+    font-weight: 600 !important;
+}
+
+/* ----- KPI / Metric cards ----- */
+[data-testid="stMetric"] {
+    background-color: #FFFFFF;
+    border-radius: 12px;
+    padding: 16px 20px;
+    border-left: 4px solid #1E5BA8;
+    box-shadow: 0 1px 3px rgba(15, 20, 25, 0.06),
+                0 1px 2px rgba(15, 20, 25, 0.04);
+    transition: box-shadow 0.2s ease, transform 0.2s ease;
+}
+
+[data-testid="stMetric"]:hover {
+    box-shadow: 0 4px 12px rgba(30, 91, 168, 0.10),
+                0 2px 4px rgba(15, 20, 25, 0.06);
+    transform: translateY(-1px);
+}
+
+[data-testid="stMetricValue"] {
+    font-family: 'JetBrains Mono', monospace !important;
+    font-weight: 700 !important;
+    font-size: 1.85rem !important;
+    color: #1F3464 !important;
+}
+
+[data-testid="stMetricLabel"] {
+    font-size: 0.72rem !important;
+    color: #6B7280 !important;
+    text-transform: uppercase;
+    letter-spacing: 0.08em;
+    font-weight: 600 !important;
+}
+
+[data-testid="stMetricDelta"] {
+    font-family: 'JetBrains Mono', monospace !important;
+    font-size: 0.85rem !important;
+    font-weight: 500 !important;
+}
+
+/* ----- Sidebar ----- */
+[data-testid="stSidebar"] {
+    background-color: #E8EDF3;
+    border-right: 1px solid #B9D9EB;
+}
+
+[data-testid="stSidebar"] .stMarkdown,
+[data-testid="stSidebar"] label,
+[data-testid="stSidebar"] [data-testid="stWidgetLabel"] p {
+    color: #1F3464 !important;
+    font-weight: 600 !important;
+}
+
+[data-testid="stSidebar"] h1,
+[data-testid="stSidebar"] h2,
+[data-testid="stSidebar"] h3 {
+    color: #1F3464 !important;
+    font-family: 'Space Grotesk', sans-serif !important;
+}
+
+[data-testid="stSidebar"] h2::before,
+[data-testid="stSidebar"] h3::before {
+    display: none;
+}
+
+/* Sidebar widgets */
+[data-testid="stSidebar"] [data-baseweb="select"] > div,
+[data-testid="stSidebar"] input,
+[data-testid="stSidebar"] textarea {
+    background-color: #FFFFFF !important;
+    border-color: #B9D9EB !important;
+}
+
+[data-testid="stSidebar"] [data-baseweb="slider"] [role="slider"] {
+    background-color: #1E5BA8 !important;
+}
+
+/* ----- Buttons ----- */
+.stButton > button,
+[data-testid="stBaseButton-secondary"] {
+    background-color: #1E5BA8;
+    color: #FFFFFF !important;
+    border: none;
+    border-radius: 8px;
+    padding: 8px 16px;
+    font-weight: 500;
+    transition: background-color 0.15s ease, transform 0.15s ease;
+}
+
+.stButton > button:hover {
+    background-color: #1F3464;
+    transform: translateY(-1px);
+}
+
+/* ----- Tabs ----- */
+[data-testid="stTabs"] [data-baseweb="tab-list"] {
+    gap: 4px;
+    border-bottom: 2px solid #B9D9EB;
+}
+
+[data-testid="stTabs"] [data-baseweb="tab"] {
+    background-color: transparent;
+    color: #6B7280;
+    font-weight: 500;
+    font-family: 'Space Grotesk', sans-serif;
+    border-radius: 8px 8px 0 0;
+    padding: 8px 16px;
+}
+
+[data-testid="stTabs"] [data-baseweb="tab"][aria-selected="true"] {
+    color: #1E5BA8;
+    background-color: rgba(30, 91, 168, 0.08);
+    border-bottom: 3px solid #1E5BA8;
+}
+
+/* ----- Info / Warning / Success / Error boxes ----- */
+[data-testid="stAlert"],
+[data-testid="stNotification"] {
+    border-radius: 10px;
+    border-left-width: 4px;
+}
+
+/* Info — Ocean Blue */
+[data-testid="stAlert"][kind="info"],
+div[data-baseweb="notification"][kind="info"],
+.stAlert.st-info {
+    background-color: rgba(30, 91, 168, 0.08) !important;
+    border-left-color: #1E5BA8 !important;
+    color: #1F3464 !important;
+}
+
+/* Warning — Penguin Orange */
+[data-testid="stAlert"][kind="warning"] {
+    background-color: rgba(243, 156, 92, 0.10) !important;
+    border-left-color: #F39C5C !important;
+    color: #7C4A1E !important;
+}
+
+/* Success — Sky Blue */
+[data-testid="stAlert"][kind="success"] {
+    background-color: rgba(91, 169, 221, 0.10) !important;
+    border-left-color: #5BA9DD !important;
+}
+
+/* ----- Radio / Multiselect / Selectbox ----- */
+[data-baseweb="select"] > div,
+.stSelectbox > div > div,
+.stMultiSelect > div > div {
+    border-color: #B9D9EB !important;
+    border-radius: 8px;
+}
+
+[data-baseweb="tag"] {
+    background-color: rgba(30, 91, 168, 0.10) !important;
+    color: #1F3464 !important;
+}
+
+/* ----- Dividers ----- */
+hr, [data-testid="stDivider"] {
+    border-top: 1px solid #B9D9EB !important;
+    background: transparent !important;
+}
+
+/* ----- Captions ----- */
+[data-testid="stCaptionContainer"], .stCaption,
+small, .small {
+    color: #6B7280 !important;
+    font-style: italic;
+}
+
+/* ----- Expander ----- */
+[data-testid="stExpander"] {
+    border: 1px solid #B9D9EB !important;
+    border-radius: 10px !important;
+    background-color: #FFFFFF;
+}
+
+[data-testid="stExpander"] summary {
+    color: #1F3464 !important;
+    font-weight: 600;
+    font-family: 'Space Grotesk', sans-serif;
+}
+
+/* ----- DataFrame ----- */
+[data-testid="stDataFrame"] {
+    border-radius: 10px;
+    overflow: hidden;
+    border: 1px solid #B9D9EB;
+}
+
+/* ----- Hide Streamlit chrome ----- */
+#MainMenu { visibility: hidden; }
+footer { visibility: hidden; }
+header [data-testid="stToolbar"] { visibility: hidden; }
+[data-testid="stDecoration"] { display: none; }
+
+/* ----- Scrollbar (WebKit) ----- */
+::-webkit-scrollbar {
+    width: 10px;
+    height: 10px;
+}
+::-webkit-scrollbar-track {
+    background: #F4F7FA;
+}
+::-webkit-scrollbar-thumb {
+    background: #B9D9EB;
+    border-radius: 6px;
+    border: 2px solid #F4F7FA;
+}
+::-webkit-scrollbar-thumb:hover {
+    background: #5BA9DD;
+}
+
+/* ----- Sidebar image polish ----- */
+[data-testid="stSidebar"] [data-testid="stImage"] img {
+    border-radius: 8px;
+}
diff --git a/chart_theme.py b/chart_theme.py
new file mode 100644
index 0000000..53334a5
--- /dev/null
+++ b/chart_theme.py
@@ -0,0 +1,28 @@
+"""Unified Plotly theme for Bouncing Penguin dashboard."""
+
+PENGUIN_PALETTE = [
+    "#1E5BA8",
+    "#F39C5C",
+    "#5BA9DD",
+    "#1F3464",
+    "#B9D9EB",
+    "#0F8B8D",
+    "#9B6B9E",
+]
+
+PENGUIN_LAYOUT = dict(
+    plot_bgcolor="rgba(0,0,0,0)",
+    paper_bgcolor="rgba(0,0,0,0)",
+    font=dict(family="Inter, sans-serif", color="#0F1419", size=13),
+    colorway=PENGUIN_PALETTE,
+    xaxis=dict(gridcolor="#E8EDF3", zerolinecolor="#E8EDF3"),
+    yaxis=dict(gridcolor="#E8EDF3", zerolinecolor="#E8EDF3"),
+    legend=dict(bgcolor="rgba(0,0,0,0)"),
+    hoverlabel=dict(bgcolor="#1F3464", font=dict(color="#FFFFFF", family="Inter")),
+)
+
+
+def apply_penguin_theme(fig):
+    """Apply Bouncing Penguin theme to a Plotly figure (in-place)."""
+    fig.update_layout(**PENGUIN_LAYOUT)
+    return fig
diff --git a/pages/2_Second_Dataset.py b/pages/2_Second_Dataset.py
index 6d74619..b8e3525 100644
--- a/pages/2_Second_Dataset.py
+++ b/pages/2_Second_Dataset.py
@@ -1,4 +1,5 @@
 from datetime import date, timedelta
+from pathlib import Path
 
 import streamlit as st
 
@@ -6,6 +7,12 @@
 
 st.set_page_config(page_title="NYC COVID Data", layout="wide")
 
+# ===== UI Style Sync =====
+_css = Path(__file__).parent.parent / "assets" / "style.css"
+if _css.exists():
+    st.markdown(f"<style>{_css.read_text()}</style>", unsafe_allow_html=True)
+# ========================
+
 
 def main() -> None:
     st.title("NYC COVID-19 Cases")
diff --git a/requirements.txt b/requirements.txt
index ae4b34f..f307a28 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,7 @@
 streamlit
 pandas
 plotly
+Pillow
 requests
 ruff
 pytest
diff --git a/streamlit_app.py b/streamlit_app.py
index 6274b4b..cecb75d 100644
--- a/streamlit_app.py
+++ b/streamlit_app.py
@@ -1,11 +1,14 @@
 from datetime import date, timedelta
+from pathlib import Path
 
 import pandas as pd
 import plotly.express as px
 import plotly.graph_objects as go
 import streamlit as st
+from PIL import Image
 from plotly.subplots import make_subplots
 
+from chart_theme import PENGUIN_PALETTE, apply_penguin_theme
 from utils import (
     MODE_COLORS,
     MTA_MIN_DATE,
@@ -19,7 +22,49 @@
     load_mta_data,
 )
 
-st.set_page_config(page_title="MTA Ridership Dashboard", layout="wide")
+_PENGUIN_ICON = Path(__file__).parent / "assets" / "bouncing_penguin.png"
+st.set_page_config(
+    page_title="MTA Ridership Dashboard",
+    layout="wide",
+    page_icon=Image.open(_PENGUIN_ICON) if _PENGUIN_ICON.exists() else "🐧",
+)
+
+# ===== UI Customization Block - START =====
+_css_path = Path(__file__).parent / "assets" / "style.css"
+if _css_path.exists():
+    st.markdown(f"<style>{_css_path.read_text()}</style>", unsafe_allow_html=True)
+
+with st.sidebar:
+    _sipa_logo = Path(__file__).parent / "assets" / "sipa_logo.png"
+    if _sipa_logo.exists():
+        st.image(str(_sipa_logo), width="stretch")
+
+    _penguin = Path(__file__).parent / "assets" / "bouncing_penguin.png"
+    if _penguin.exists():
+        _c1, _c2, _c3 = st.columns([1, 3, 1])
+        with _c2:
+            st.image(str(_penguin), width="stretch")
+
+    st.markdown(
+        """
+        <div style='text-align:center; padding: 8px 0 16px 0;'>
+            <div style='font-family: "Space Grotesk", sans-serif;
+                        font-weight: 700; font-size: 1.1rem;
+                        color: #1F3464; line-height: 1.2;'>
+                Bouncing Penguin
+            </div>
+            <div style='font-family: "Inter", sans-serif;
+                        font-size: 0.8rem; color: #6B7280;
+                        font-style: italic; margin-top: 4px;'>
+                Advanced Computing &middot; Columbia SIPA
+            </div>
+        </div>
+        <hr style='margin: 0 0 12px 0; border: none;
+                   border-top: 1px solid #B9D9EB;' />
+        """,
+        unsafe_allow_html=True,
+    )
+# ===== UI Customization Block - END =====
 
 
 def get_dashboard_columns(selected_modes: list[str]) -> tuple[str, ...]:
@@ -222,6 +267,7 @@ def render_recovery_chart(
         legend_title_text="",
     )
     fig.update_yaxes(ticksuffix="%", rangemode="tozero")
+    apply_penguin_theme(fig)
     st.plotly_chart(fig, width="stretch", config={"displayModeBar": False})
 
     insight_lines = []
@@ -266,6 +312,7 @@ def render_total_chart(
         yaxis_title="Daily Ridership / Traffic",
         legend_title_text="",
     )
+    apply_penguin_theme(fig)
     st.plotly_chart(fig, width="stretch", config={"displayModeBar": False})
     st.caption(
         "Even where recovery percentages plateau, raw ridership still trends up — "
@@ -293,7 +340,7 @@ def render_subway_day_type_summary(filtered: pd.DataFrame) -> None:
         x="Day Type",
         y=subway_column,
         color="Day Type",
-        color_discrete_map={"Weekday": "#2563eb", "Weekend": "#f97316"},
+        color_discrete_map={"Weekday": "#1E5BA8", "Weekend": "#F39C5C"},
     )
     fig.update_layout(
         height=260,
@@ -302,6 +349,7 @@ def render_subway_day_type_summary(filtered: pd.DataFrame) -> None:
         yaxis_title="Average Subway Ridership",
         showlegend=False,
     )
+    apply_penguin_theme(fig)
     st.plotly_chart(fig, width="stretch", config={"displayModeBar": False})
     if not averages.empty and len(averages) == 2:
         weekday_val = averages.loc[averages["Day Type"] == "Weekday", subway_column].mean()
@@ -345,6 +393,7 @@ def render_mode_recovery_summary(filtered: pd.DataFrame) -> None:
         showlegend=False,
     )
     fig.update_yaxes(ticksuffix="%", rangemode="tozero")
+    apply_penguin_theme(fig)
     st.plotly_chart(fig, width="stretch", config={"displayModeBar": False})
 
 
@@ -383,7 +432,7 @@ def render_weekday_weekend(filtered: pd.DataFrame) -> None:
         color="Day Type",
         barmode="group",
         category_orders={"Day Type": ["Weekday", "Weekend"]},
-        color_discrete_sequence=["#7dd3fc", "#2563eb"],
+        color_discrete_sequence=["#5BA9DD", "#1E5BA8"],
     )
     comparison_fig.update_layout(
         height=320,
@@ -392,6 +441,7 @@ def render_weekday_weekend(filtered: pd.DataFrame) -> None:
         legend_title_text="",
     )
     comparison_fig.update_yaxes(ticksuffix="%", rangemode="tozero")
+    apply_penguin_theme(comparison_fig)
     st.plotly_chart(comparison_fig, width="stretch", config={"displayModeBar": False})
 
     st.markdown("**Monthly Weekend Minus Weekday Gap (Subway)**")
@@ -425,6 +475,7 @@ def render_weekday_weekend(filtered: pd.DataFrame) -> None:
         coloraxis_showscale=False,
     )
     gap_fig.update_yaxes(ticksuffix="%", zeroline=True, zerolinewidth=1)
+    apply_penguin_theme(gap_fig)
     st.plotly_chart(gap_fig, width="stretch", config={"displayModeBar": False})
 
 
@@ -487,6 +538,7 @@ def render_holiday_impact(filtered: pd.DataFrame) -> None:
         showlegend=False,
     )
     fig.update_yaxes(ticksuffix="%", rangemode="tozero")
+    apply_penguin_theme(fig)
     st.plotly_chart(fig, width="stretch", config={"displayModeBar": False})
 
     impact_rows = []
@@ -548,7 +600,7 @@ def render_yearly_recovery(filtered: pd.DataFrame) -> None:
         y="Avg Recovery Percent",
         color="Transit Mode",
         barmode="group",
-        color_discrete_sequence=["#60a5fa", "#f97316", "#ef4444", "#34d399", "#a78bfa"],
+        color_discrete_sequence=PENGUIN_PALETTE,
     )
     yearly_fig.update_layout(
         height=340,
@@ -557,6 +609,7 @@ def render_yearly_recovery(filtered: pd.DataFrame) -> None:
         legend_title_text="",
     )
     yearly_fig.update_yaxes(ticksuffix="%", rangemode="tozero")
+    apply_penguin_theme(yearly_fig)
     st.plotly_chart(yearly_fig, width="stretch", config={"displayModeBar": False})
 
 
@@ -669,7 +722,7 @@ def render_covid_context(
             y=combined["Subway Recovery Percent"],
             name="Subway recovery",
             mode="lines",
-            line=dict(color=MODE_COLORS["Subway"], width=2),
+            line=dict(color="#1E5BA8", width=2),
         ),
         secondary_y=False,
     )
@@ -679,7 +732,7 @@ def render_covid_context(
             y=combined["COVID Cases"],
             name="COVID cases",
             mode="lines",
-            line=dict(color="#dc2626", width=2),
+            line=dict(color="#F39C5C", width=2),
         ),
         secondary_y=True,
     )
@@ -691,6 +744,7 @@ def render_covid_context(
     fig.update_xaxes(title_text="Date")
     fig.update_yaxes(title_text="Subway Recovery", ticksuffix="%", secondary_y=False)
     fig.update_yaxes(title_text="COVID Cases", secondary_y=True)
+    apply_penguin_theme(fig)
     st.plotly_chart(fig, width="stretch", config={"displayModeBar": False})
 
     st.caption(