ui <- fluidPage(
  useShinyjs(),

  tags$head(
    # Google Fonts - Professional pairing
    tags$link(
      href = "https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:wght@400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap",
      rel = "stylesheet"
    ),

    tags$style(HTML("
      /* =======================================================================
         WVU BASEBALL ANALYTICS - PROFESSIONAL UI
         ======================================================================= */

      /* CSS Variables */
      :root {
        --wvu-navy: #002855;
        --wvu-navy-dark: #001a3a;
        --wvu-navy-light: #003875;
        --wvu-gold: #EAAA00;
        --wvu-gold-light: #f5c131;
        --wvu-gold-dark: #c99400;
        --white: #FFFFFF;
        --gray-50: #f8fafc;
        --gray-100: #f1f5f9;
        --gray-200: #e2e8f0;
        --gray-300: #cbd5e1;
        --gray-400: #94a3b8;
        --gray-500: #64748b;
        --gray-600: #475569;
        --gray-700: #334155;
        --gray-800: #1e293b;

        --radius-sm: 6px;
        --radius-md: 10px;
        --radius-lg: 14px;
        --radius-xl: 20px;

        --shadow-xs: 0 1px 2px rgba(0, 40, 85, 0.05);
        --shadow-sm: 0 1px 3px rgba(0, 40, 85, 0.08), 0 1px 2px rgba(0, 40, 85, 0.06);
        --shadow-md: 0 4px 6px -1px rgba(0, 40, 85, 0.08), 0 2px 4px -2px rgba(0, 40, 85, 0.06);
        --shadow-lg: 0 10px 15px -3px rgba(0, 40, 85, 0.1), 0 4px 6px -4px rgba(0, 40, 85, 0.08);
        --shadow-xl: 0 20px 25px -5px rgba(0, 40, 85, 0.1), 0 8px 10px -6px rgba(0, 40, 85, 0.08);

        --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
        --transition-base: 200ms cubic-bezier(0.4, 0, 0.2, 1);
        --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);
      }

      /* Reset & Base */
      *, *::before, *::after {
        box-sizing: border-box;
      }

      html, body {
        margin: 0;
        padding: 0;
        font-family: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, sans-serif;
        font-size: 14px;
        line-height: 1.5;
        color: var(--gray-800);
        background: var(--gray-50);
        -webkit-font-smoothing: antialiased;
        -moz-osx-font-smoothing: grayscale;
      }

      .container-fluid {
        padding: 0 !important;
        margin: 0 !important;
        max-width: 100% !important;
      }

      /* =======================================================================
         LOGIN PAGE - Split Screen Design
         ======================================================================= */

      .login-container {
        position: fixed;
        inset: 0;
        display: flex;
        background: var(--white);
      }

      /* Left side - Image */
      .login-image {
        flex: 1;
        position: relative;
        overflow: hidden;
        display: none;
      }

      @media (min-width: 900px) {
        .login-image {
          display: block;
        }
      }

      .login-image img {
        width: 100%;
        height: 100%;
        object-fit: cover;
      }

      .login-image::after {
        content: '';
        position: absolute;
        inset: 0;
        background: linear-gradient(
          135deg,
          rgba(0, 40, 85, 0.7) 0%,
          rgba(0, 26, 58, 0.85) 100%
        );
      }

      .login-image-content {
        position: absolute;
        bottom: 48px;
        left: 48px;
        right: 48px;
        z-index: 1;
        color: var(--white);
      }

      .login-image-content h2 {
        font-size: 32px;
        font-weight: 700;
        margin: 0 0 12px 0;
        line-height: 1.2;
      }

      .login-image-content p {
        font-size: 16px;
        opacity: 0.85;
        margin: 0;
        max-width: 400px;
      }

      /* Right side - Form */
      .login-form-side {
        flex: 0 0 480px;
        display: flex;
        flex-direction: column;
        justify-content: center;
        padding: 48px;
        background: var(--white);
      }

      @media (max-width: 899px) {
        .login-form-side {
          flex: 1;
          background-image: linear-gradient(
            rgba(255, 255, 255, 0.92),
            rgba(255, 255, 255, 0.92)
          ), url('https://images.sidearmdev.com/crop?url=https%3a%2f%2fdxbhsrqyrr690.cloudfront.net%2fsidearm.nextgen.sites%2fwvuni.sidearmsports.com%2fimages%2f2025%2f2%2f18%2fWVU02765_large.jpg&height=563&width=1000&type=webp');
          background-size: cover;
          background-position: center;
        }
      }

      .login-form-wrapper {
        max-width: 340px;
        margin: 0 auto;
        width: 100%;
      }

      .login-logo {
        display: flex;
        align-items: center;
        gap: 16px;
        margin-bottom: 40px;
      }

      .login-logo img {
        height: 56px;
        width: auto;
      }

      .login-logo-text {
        border-left: 2px solid var(--gray-200);
        padding-left: 16px;
      }

      .login-logo-text h1 {
        font-size: 18px;
        font-weight: 700;
        color: var(--wvu-navy);
        margin: 0;
        line-height: 1.2;
      }

      .login-logo-text span {
        font-size: 13px;
        color: var(--gray-500);
        font-weight: 500;
      }

      .login-form-wrapper h2 {
        font-size: 26px;
        font-weight: 700;
        color: var(--wvu-navy);
        margin: 0 0 8px 0;
      }

      .login-form-wrapper .subtitle {
        font-size: 15px;
        color: var(--gray-500);
        margin: 0 0 32px 0;
      }

      .login-form-wrapper .form-group {
        margin-bottom: 20px;
      }

      .login-form-wrapper .control-label {
        display: block;
        font-size: 13px;
        font-weight: 600;
        color: var(--gray-700) !important;
        margin-bottom: 6px;
        text-transform: none !important;
        letter-spacing: 0 !important;
      }

      .login-form-wrapper .form-control {
        width: 100%;
        padding: 12px 14px !important;
        border: 1.5px solid var(--gray-300) !important;
        border-radius: var(--radius-md) !important;
        font-size: 15px !important;
        font-family: inherit !important;
        background: var(--white) !important;
        transition: all var(--transition-fast) !important;
      }

      .login-form-wrapper .form-control:focus {
        border-color: var(--wvu-navy) !important;
        box-shadow: 0 0 0 3px rgba(0, 40, 85, 0.1) !important;
        outline: none !important;
      }

      .login-form-wrapper .btn {
        width: 100%;
        padding: 14px 20px !important;
        margin-top: 8px;
        font-family: inherit !important;
        font-size: 15px !important;
        font-weight: 600 !important;
        background: var(--wvu-navy) !important;
        border: none !important;
        border-radius: var(--radius-md) !important;
        color: var(--white) !important;
        cursor: pointer;
        transition: all var(--transition-fast) !important;
      }

      .login-form-wrapper .btn:hover {
        background: var(--wvu-navy-light) !important;
        transform: translateY(-1px);
        box-shadow: var(--shadow-md);
      }

      .login-form-wrapper .btn:active {
        transform: translateY(0);
      }

      /* =======================================================================
         NAVIGATION
         ======================================================================= */

      .navbar-main {
        background: var(--wvu-navy);
        padding: 0 24px;
        display: flex;
        justify-content: space-between;
        align-items: center;
        height: 60px;
        position: sticky;
        top: 0;
        z-index: 1000;
        box-shadow: var(--shadow-md);
      }

      .nav-left {
        display: flex;
        align-items: center;
        gap: 4px;
        height: 100%;
      }

      .nav-logo {
        height: 36px;
        width: auto;
        margin-right: 20px;
      }

      .nav-dropdown {
        position: relative;
        height: 100%;
      }

      .nav-dropdown > button {
        height: 60px;
        padding: 0 18px !important;
        background: transparent !important;
        border: none !important;
        color: rgba(255, 255, 255, 0.9) !important;
        font-family: inherit !important;
        font-size: 14px !important;
        font-weight: 600 !important;
        cursor: pointer !important;
        transition: all var(--transition-fast) !important;
        position: relative !important;
      }

      .nav-dropdown > button::after {
        content: '';
        position: absolute;
        bottom: 0;
        left: 50%;
        transform: translateX(-50%) scaleX(0);
        width: calc(100% - 20px);
        height: 3px;
        background: var(--wvu-gold);
        transition: transform var(--transition-base);
        border-radius: 3px 3px 0 0;
      }

      .nav-dropdown:hover > button {
        color: var(--white) !important;
        background: rgba(255, 255, 255, 0.08) !important;
      }

      .nav-dropdown:hover > button::after {
        transform: translateX(-50%) scaleX(1);
      }

      .nav-submenu {
        position: absolute;
        top: calc(100% + 4px);
        left: 0;
        min-width: 200px;
        background: var(--white);
        border-radius: var(--radius-lg);
        box-shadow: var(--shadow-xl);
        padding: 6px;
        display: none;
        z-index: 1000;
        border: 1px solid var(--gray-100);
      }

      .nav-dropdown:hover .nav-submenu {
        display: block;
        animation: dropdownFade 0.15s ease-out;
      }

      @keyframes dropdownFade {
        from { opacity: 0; transform: translateY(-4px); }
        to { opacity: 1; transform: translateY(0); }
      }

      .nav-submenu::before {
        content: '';
        position: absolute;
        top: -6px;
        left: 0;
        right: 0;
        height: 6px;
      }

      .nav-submenu button {
        display: block !important;
        width: 100% !important;
        padding: 10px 14px !important;
        background: var(--white) !important;
        border: none !important;
        border-radius: var(--radius-sm) !important;
        color: var(--wvu-navy) !important;
        font-family: inherit !important;
        font-size: 14px !important;
        font-weight: 500 !important;
        text-align: left !important;
        cursor: pointer !important;
        transition: all var(--transition-fast) !important;
      }

      .nav-submenu button:hover {
        background: var(--wvu-gold) !important;
        color: var(--wvu-navy) !important;
      }

      /* =======================================================================
         SELECTION OPTIONS (Header controls)
         ======================================================================= */

      #selection_options {
        display: flex;
        align-items: center;
        gap: 10px;
        height: 100%;
        padding: 10px 0;
      }

      #selection_options > div > div {
        display: flex;
        align-items: center;
        gap: 10px;
      }

      #selection_options .form-group {
        margin: 0 !important;
      }

      #selection_options .control-label {
        font-size: 10px !important;
        font-weight: 600 !important;
        text-transform: uppercase !important;
        letter-spacing: 0.5px !important;
        color: rgba(255, 255, 255, 0.6) !important;
        margin-bottom: 4px !important;
        display: block !important;
      }

      /* =======================================================================
         FORM CONTROLS
         ======================================================================= */

      .form-control, .selectize-input {
        border: 1.5px solid var(--gray-200) !important;
        border-radius: var(--radius-md) !important;
        padding: 9px 12px !important;
        font-family: 'Plus Jakarta Sans', sans-serif !important;
        font-size: 14px !important;
        font-weight: 500 !important;
        background: var(--white) !important;
        color: var(--gray-800) !important;
        transition: all var(--transition-fast) !important;
        box-shadow: var(--shadow-xs) !important;
      }

      .form-control:focus, .selectize-input.focus {
        border-color: var(--wvu-navy) !important;
        box-shadow: 0 0 0 3px rgba(0, 40, 85, 0.1), var(--shadow-xs) !important;
        outline: none !important;
      }

      .selectize-input {
        min-height: 40px !important;
        display: flex !important;
        align-items: center !important;
      }

      .selectize-dropdown {
        border: 1px solid var(--gray-200) !important;
        border-radius: var(--radius-lg) !important;
        box-shadow: var(--shadow-lg) !important;
        margin-top: 4px !important;
        background: var(--white) !important;
        overflow: hidden;
      }

      .selectize-dropdown-content {
        max-height: 280px !important;
        padding: 6px !important;
      }

      .selectize-dropdown .option {
        padding: 10px 12px !important;
        border-radius: var(--radius-sm) !important;
        margin: 2px 0 !important;
        font-weight: 500 !important;
        color: var(--gray-700) !important;
        transition: all var(--transition-fast) !important;
      }

      .selectize-dropdown .option:hover,
      .selectize-dropdown .option.active {
        background: var(--gray-100) !important;
        color: var(--wvu-navy) !important;
      }

      .selectize-dropdown .option.selected {
        background: var(--wvu-navy) !important;
        color: var(--white) !important;
      }

      .control-label {
        font-family: 'Plus Jakarta Sans', sans-serif !important;
        font-size: 13px !important;
        font-weight: 600 !important;
        color: var(--gray-600) !important;
        margin-bottom: 6px !important;
        display: block !important;
      }

      input[type='number'] {
        font-family: 'JetBrains Mono', monospace !important;
      }

      /* =======================================================================
         BUTTONS
         ======================================================================= */

      .btn {
        font-family: 'Plus Jakarta Sans', sans-serif !important;
        font-weight: 600 !important;
        border-radius: var(--radius-md) !important;
        padding: 10px 18px !important;
        transition: all var(--transition-fast) !important;
        cursor: pointer !important;
      }

      .btn-primary {
        background: var(--wvu-navy) !important;
        border: none !important;
        color: var(--white) !important;
        box-shadow: var(--shadow-sm) !important;
      }

      .btn-primary:hover {
        background: var(--wvu-navy-light) !important;
        transform: translateY(-1px) !important;
        box-shadow: var(--shadow-md) !important;
      }

      .btn-default {
        background: var(--white) !important;
        color: var(--gray-700) !important;
        border: 1.5px solid var(--gray-200) !important;
      }

      .btn-default:hover {
        border-color: var(--gray-300) !important;
        background: var(--gray-50) !important;
      }

      .btn-default.shiny-download-link {
        display: inline-flex !important;
        align-items: center !important;
        gap: 6px !important;
      }

      /* =======================================================================
         MAIN CONTENT
         ======================================================================= */

      #main_content {
        padding: 28px !important;
        background: var(--gray-50) !important;
        min-height: calc(100vh - 60px) !important;
      }

      .well, .panel {
        background: transparent !important;
        border: none !important;
        box-shadow: none !important;
        padding: 0 !important;
        margin: 0 !important;
      }

      /* =======================================================================
         PLOTS
         ======================================================================= */

      .shiny-plot-output {
        background: var(--white);
        border-radius: 0;
        box-shadow: var(--shadow-sm);
        overflow: hidden;
      }

      .plotly {
        border-radius: 0;
        overflow: hidden;
      }

      /* =======================================================================
         DATA TABLES - Styled to match GT tables with WVU branding
         ======================================================================= */

      .dataTables_wrapper {
        padding: 20px;
        background: var(--white);
        border-radius: var(--radius-lg);
        box-shadow: var(--shadow-sm);
        border: 1px solid var(--wvu-navy);
      }

      .dataTables_wrapper .dataTables_length,
      .dataTables_wrapper .dataTables_filter,
      .dataTables_wrapper .dataTables_info,
      .dataTables_wrapper .dataTables_paginate {
        font-family: 'Plus Jakarta Sans', sans-serif;
        font-size: 13px;
        color: var(--wvu-navy);
      }

      .dataTables_wrapper .dataTables_length select {
        border: 1px solid var(--wvu-navy) !important;
        border-radius: var(--radius-sm) !important;
        padding: 4px 8px !important;
        color: var(--wvu-navy) !important;
      }

      .dataTables_wrapper .dataTables_filter input {
        border: 1.5px solid var(--wvu-navy);
        border-radius: var(--radius-md);
        padding: 8px 12px;
        margin-left: 8px;
        transition: all var(--transition-fast);
        color: var(--wvu-navy);
      }

      .dataTables_wrapper .dataTables_filter input:focus {
        border-color: var(--wvu-gold);
        outline: none;
        box-shadow: 0 0 0 3px rgba(234, 170, 0, 0.2);
      }

      .dataTable {
        border-collapse: collapse !important;
        border-spacing: 0 !important;
        width: 100% !important;
        border: 1px solid var(--wvu-navy) !important;
      }

      .dataTable thead th {
        background: var(--wvu-gold) !important;
        color: var(--wvu-navy) !important;
        font-family: 'Plus Jakarta Sans', sans-serif !important;
        font-size: 12px !important;
        font-weight: 700 !important;
        text-transform: uppercase !important;
        letter-spacing: 0.3px !important;
        padding: 12px 14px !important;
        border: 0.5px solid var(--wvu-navy) !important;
        text-align: center !important;
      }

      .dataTable thead th:first-child {
        border-radius: 0 !important;
      }

      .dataTable thead th:last-child {
        border-radius: 0 !important;
      }

      /* Sorting icons styling */
      .dataTable thead th.sorting,
      .dataTable thead th.sorting_asc,
      .dataTable thead th.sorting_desc {
        background: var(--wvu-gold) !important;
        color: var(--wvu-navy) !important;
      }

      .dataTable thead th.sorting:after,
      .dataTable thead th.sorting_asc:after,
      .dataTable thead th.sorting_desc:after {
        color: var(--wvu-navy) !important;
        opacity: 0.7;
      }

      .dataTable tbody td {
        padding: 10px 14px !important;
        font-family: 'Plus Jakarta Sans', sans-serif !important;
        font-size: 13px !important;
        border: 0.5px solid var(--wvu-navy) !important;
        color: var(--wvu-navy) !important;
        text-align: center !important;
      }

      .dataTable tbody tr:hover td {
        background: rgba(234, 170, 0, 0.1) !important;
      }

      .dataTable tbody tr:last-child td:first-child {
        border-radius: 0;
      }

      .dataTable tbody tr:last-child td:last-child {
        border-radius: 0;
      }

      /* Filter inputs in header row */
      .dataTable thead input,
      .dataTable thead select {
        border: 1px solid var(--wvu-navy) !important;
        border-radius: var(--radius-sm) !important;
        padding: 4px 6px !important;
        font-size: 11px !important;
        color: var(--wvu-navy) !important;
        background: var(--white) !important;
        width: 100% !important;
        margin-top: 4px !important;
      }

      .dataTables_wrapper .dataTables_paginate .paginate_button {
        border-radius: var(--radius-sm) !important;
        padding: 6px 12px !important;
        margin: 0 2px !important;
        border: 1px solid var(--wvu-navy) !important;
        font-weight: 500 !important;
        transition: all var(--transition-fast) !important;
        color: var(--wvu-navy) !important;
        background: var(--white) !important;
      }

      .dataTables_wrapper .dataTables_paginate .paginate_button:hover {
        background: var(--wvu-gold) !important;
        color: var(--wvu-navy) !important;
        border-color: var(--wvu-navy) !important;
      }

      .dataTables_wrapper .dataTables_paginate .paginate_button.current {
        background: var(--wvu-gold) !important;
        color: var(--wvu-navy) !important;
        font-weight: 700 !important;
        border-color: var(--wvu-navy) !important;
      }

      .dataTables_wrapper .dataTables_paginate .paginate_button.disabled {
        color: var(--gray-400) !important;
        background: var(--gray-100) !important;
        border-color: var(--gray-300) !important;
      }

      /* =======================================================================
         GT TABLES - Updated to match DataTable styling
         ======================================================================= */

      .gt_table {
        border-radius: 0 !important;
        overflow: hidden !important;
        box-shadow: var(--shadow-sm) !important;
        font-family: 'Plus Jakarta Sans', sans-serif !important;
        border: 1px solid var(--wvu-navy) !important;
      }

      /* =======================================================================
         LAYOUT
         ======================================================================= */

      .row {
        margin-left: -14px !important;
        margin-right: -14px !important;
      }

      .col-sm-1, .col-sm-2, .col-sm-3, .col-sm-4, .col-sm-5, .col-sm-6,
      .col-sm-7, .col-sm-8, .col-sm-9, .col-sm-10, .col-sm-11, .col-sm-12 {
        padding-left: 14px !important;
        padding-right: 14px !important;
      }

      /* =======================================================================
         ANIMATIONS
         ======================================================================= */

      .shiny-bound-output {
        animation: contentFade 0.25s ease-out;
      }

      @keyframes contentFade {
        from { opacity: 0; transform: translateY(6px); }
        to { opacity: 1; transform: translateY(0); }
      }

      /* =======================================================================
         RESPONSIVE
         ======================================================================= */

      @media (max-width: 1200px) {
        .navbar-main {
          padding: 0 16px;
        }

        #main_content {
          padding: 20px !important;
        }
      }

      @media (max-width: 992px) {
        .nav-dropdown > button {
          padding: 0 12px !important;
          font-size: 13px !important;
        }
      }

      @media (max-width: 768px) {
        .navbar-main {
          flex-direction: column;
          height: auto;
          padding: 12px;
        }

        .nav-left {
          width: 100%;
          justify-content: center;
          flex-wrap: wrap;
          gap: 0;
        }

        #selection_options {
          width: 100%;
          flex-wrap: wrap;
          justify-content: center;
          padding: 12px 0;
        }

        #main_content {
          padding: 16px !important;
        }
      }

      /* =======================================================================
         SCROLLBAR
         ======================================================================= */

      ::-webkit-scrollbar {
        width: 8px;
        height: 8px;
      }

      ::-webkit-scrollbar-track {
        background: var(--gray-100);
        border-radius: 4px;
      }

      ::-webkit-scrollbar-thumb {
        background: var(--gray-300);
        border-radius: 4px;
      }

      ::-webkit-scrollbar-thumb:hover {
        background: var(--gray-400);
      }
    "))
  ),

  uiOutput("login_ui"),
  uiOutput("app_ui")
)