:root{--color-primary: #007bff;--color-primary-hover: #0056b3;--color-primary-light: #e7f3ff;--color-secondary: #6c757d;--color-secondary-hover: #545b62;--color-success: #28a745;--color-success-hover: #1e7e34;--color-success-light: #d4edda;--color-warning: #ffc107;--color-warning-hover: #e0a800;--color-warning-light: #fff3cd;--color-danger: #dc3545;--color-danger-hover: #c82333;--color-danger-light: #f8d7da;--color-info: #17a2b8;--color-info-hover: #138496;--color-info-light: #d1ecf1;--bg-primary: #ffffff;--bg-secondary: #f8f9fa;--bg-tertiary: #e9ecef;--bg-quaternary: #dee2e6;--text-primary: #212529;--text-secondary: #6c757d;--text-tertiary: #adb5bd;--text-inverse: #ffffff;--border-primary: #dee2e6;--border-secondary: #e9ecef;--border-focus: #80bdff;--shadow-sm: 0 .125rem .25rem rgba(0, 0, 0, .075);--shadow: 0 .5rem 1rem rgba(0, 0, 0, .15);--shadow-lg: 0 1rem 3rem rgba(0, 0, 0, .175);--transition-fast: .15s ease-in-out;--transition-normal: .3s ease-in-out;--transition-slow: .5s ease-in-out;--radius-sm: .25rem;--radius: .375rem;--radius-lg: .5rem;--radius-xl: .75rem;--spacing-xs: .25rem;--spacing-sm: .5rem;--spacing-md: 1rem;--spacing-lg: 1.5rem;--spacing-xl: 3rem}[data-theme=dark]{--color-primary: #0d6efd;--color-primary-hover: #0b5ed7;--color-primary-light: #031633;--color-secondary: #6c757d;--color-secondary-hover: #5c636a;--color-success: #198754;--color-success-hover: #146c43;--color-success-light: #051b11;--color-warning: #ffc107;--color-warning-hover: #ffca2c;--color-warning-light: #332701;--color-danger: #dc3545;--color-danger-hover: #bb2d3b;--color-danger-light: #2c0b0e;--color-info: #0dcaf0;--color-info-hover: #3dd5f3;--color-info-light: #032830;--bg-primary: #121212;--bg-secondary: #1e1e1e;--bg-tertiary: #2d2d2d;--bg-quaternary: #3d3d3d;--text-primary: #ffffff;--text-secondary: #b3b3b3;--text-tertiary: #808080;--text-inverse: #000000;--border-primary: #404040;--border-secondary: #333333;--border-focus: #0d6efd;--shadow-sm: 0 .125rem .25rem rgba(0, 0, 0, .3);--shadow: 0 .5rem 1rem rgba(0, 0, 0, .4);--shadow-lg: 0 1rem 3rem rgba(0, 0, 0, .5)}*{box-sizing:border-box}body{background-color:var(--bg-primary);color:var(--text-primary);transition:background-color var(--transition-normal),color var(--transition-normal);font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,sans-serif;line-height:1.6;margin:0;padding:0}.bg-primary{background-color:var(--bg-primary)}.bg-secondary{background-color:var(--bg-secondary)}.bg-tertiary{background-color:var(--bg-tertiary)}.text-primary{color:var(--text-primary)}.text-secondary{color:var(--text-secondary)}.text-tertiary{color:var(--text-tertiary)}.border{border:1px solid var(--border-primary)}.border-secondary{border:1px solid var(--border-secondary)}.rounded{border-radius:var(--radius)}.rounded-lg{border-radius:var(--radius-lg)}.shadow{box-shadow:var(--shadow)}.shadow-sm{box-shadow:var(--shadow-sm)}.shadow-lg{box-shadow:var(--shadow-lg)}.transition{transition:all var(--transition-normal)}.btn{display:inline-flex;align-items:center;justify-content:center;padding:var(--spacing-sm) var(--spacing-md);border:1px solid transparent;border-radius:var(--radius);font-size:1rem;font-weight:500;text-decoration:none;cursor:pointer;transition:all var(--transition-fast);background:none}.btn-primary{background-color:var(--color-primary);color:var(--text-inverse);border-color:var(--color-primary)}.btn-primary:hover{background-color:var(--color-primary-hover);border-color:var(--color-primary-hover)}.btn-secondary{background-color:var(--color-secondary);color:var(--text-inverse);border-color:var(--color-secondary)}.btn-secondary:hover{background-color:var(--color-secondary-hover);border-color:var(--color-secondary-hover)}.btn-outline{background-color:transparent;color:var(--text-primary);border-color:var(--border-primary)}.btn-outline:hover{background-color:var(--bg-tertiary)}.card{background-color:var(--bg-secondary);border:1px solid var(--border-primary);border-radius:var(--radius-lg);padding:2rem;box-shadow:var(--shadow-sm);transition:all var(--transition-normal)}.card:hover{box-shadow:var(--shadow)}.input{width:100%;padding:var(--spacing-sm) var(--spacing-md);border:1px solid var(--border-primary);border-radius:var(--radius);background-color:var(--bg-primary);color:var(--text-primary);font-size:1rem;transition:all var(--transition-fast)}.input:focus{outline:none;border-color:var(--border-focus);box-shadow:0 0 0 .2rem #0d6efd40}.input[type=date]{color-scheme:light;cursor:pointer}[data-theme=dark] .input[type=date]{color-scheme:dark}.input[type=date]::-webkit-calendar-picker-indicator{cursor:pointer;opacity:.7;transition:opacity var(--transition-fast)}.input[type=date]::-webkit-calendar-picker-indicator:hover{opacity:1}.input[type=date]::-webkit-calendar-picker-indicator{filter:invert(1) brightness(.5) contrast(1.5);opacity:.7}.input[type=date]::-webkit-calendar-picker-indicator:hover{opacity:1;filter:invert(1) brightness(.3) contrast(1.5)}[data-theme=dark] .input[type=date]::-webkit-calendar-picker-indicator{filter:brightness(1.5) contrast(1.2);opacity:.8}[data-theme=dark] .input[type=date]::-webkit-calendar-picker-indicator:hover{opacity:1;filter:brightness(1.7) contrast(1.2)}.nav{background-color:var(--bg-secondary);border-bottom:1px solid var(--border-primary);box-shadow:var(--shadow-sm)}.nav-link{color:var(--text-primary);text-decoration:none;padding:var(--spacing-sm) var(--spacing-md);border-radius:var(--radius);transition:all var(--transition-fast)}.nav-link:hover{background-color:var(--bg-tertiary);color:var(--text-primary)}.nav-link.active{background-color:var(--color-primary);color:var(--text-inverse)}.theme-toggle{background:none;border:1px solid var(--border-primary);border-radius:var(--radius);padding:var(--spacing-sm);color:var(--text-primary);cursor:pointer;transition:all var(--transition-fast);display:flex;align-items:center;justify-content:center;width:2.5rem;height:2.5rem}.theme-toggle:hover{background-color:var(--bg-tertiary);border-color:var(--border-focus)}@media (max-width: 768px){.desktop-nav{display:none!important}.mobile-menu-btn{display:block!important}}@media (min-width: 769px){.desktop-nav{display:flex!important}.mobile-menu-btn,.mobile-menu{display:none!important}}.mobile-menu{display:block}@media (min-width: 769px){.mobile-menu{display:none!important}}@media (max-width: 768px){.pace-calculator-grid{grid-template-columns:1fr!important}.pace-time-inputs{justify-content:center!important}.pace-results-grid{grid-template-columns:repeat(2,1fr)!important}.bmi-calculator-grid{grid-template-columns:1fr!important}.bmi-height-inputs{flex-direction:column!important;gap:.5rem!important}.bmi-age-gender-grid{grid-template-columns:1fr!important;gap:1rem!important}}