:root{--color-bg-primary: #ffffff;--color-bg-secondary: #f8f9fa;--color-bg-tertiary: #e9ecef;--color-text-primary: #212529;--color-text-secondary: #6c757d;--color-text-inverse: #ffffff;--color-accent: #2c3e50;--color-accent-hover: #1a252f;--color-border: #dee2e6;--color-error: #dc3545;--spacing-xs: .25rem;--spacing-sm: .5rem;--spacing-md: 1rem;--spacing-lg: 1.5rem;--spacing-xl: 2rem;--font-family-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;--shadow-sm: 0 .125rem .25rem rgba(0, 0, 0, .075);--shadow-md: 0 .5rem 1rem rgba(0, 0, 0, .15);--shadow-lg: 0 1rem 3rem rgba(0, 0, 0, .175);--radius-sm: .25rem;--radius-md: .5rem;--radius-lg: 1rem;--radius-pill: 50rem}body.dark-theme{--color-bg-primary: #1a1d21;--color-bg-secondary: #212529;--color-bg-tertiary: #2c3035;--color-text-primary: #e9ecef;--color-text-secondary: #adb5bd;--color-text-inverse: #ffffff;--color-accent: #3498db;--color-accent-hover: #2980b9;--color-border: #343a40}html,body{height:100%;margin:0;font-family:var(--font-family-sans);background-color:var(--color-bg-secondary);color:var(--color-text-primary);-webkit-font-smoothing:antialiased}.container{max-width:800px;margin:0 auto;padding:var(--spacing-md)}.btn{display:inline-flex;align-items:center;justify-content:center;padding:var(--spacing-sm) var(--spacing-lg);font-size:1rem;font-weight:500;border-radius:var(--radius-md);border:none;cursor:pointer;transition:all .2s ease}.btn.btn-primary{background-color:var(--color-accent);color:var(--color-text-inverse)}.btn.btn-primary:hover{background-color:var(--color-accent-hover);transform:translateY(-1px)}.btn.btn-primary:disabled{opacity:.7;cursor:not-allowed;transform:none}.input-group{margin-bottom:var(--spacing-md)}.input-group label{display:block;margin-bottom:var(--spacing-xs);color:var(--color-text-secondary);font-size:.875rem}.input-group input{width:100%;padding:var(--spacing-md);border:1px solid var(--color-border);border-radius:var(--radius-md);font-size:1rem;transition:border-color .2s;box-sizing:border-box}.input-group input:focus{outline:none;border-color:var(--color-accent)}.card{background:var(--color-bg-primary);border-radius:var(--radius-lg);box-shadow:var(--shadow-sm);padding:var(--spacing-xl)}@keyframes fadeIn{0%{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}.fade-in{animation:fadeIn .3s ease-out forwards}