:root{--color-bg: #f0f2f5;--color-surface: #ffffff;--color-primary: #4f46e5;--color-primary-hover: #4338ca;--color-text: #1e293b;--color-text-muted: #64748b;--color-border: #e2e8f0;--color-success: #22c55e;--color-warning: #f59e0b;--color-error: #ef4444;--color-heading: #1e293b;--color-heading-accent: #4f46e5;--color-tier-high: #22c55e;--color-tier-mid: #6366f1;--color-tier-low: #94a3b8;--space-xs: .25rem;--space-sm: .5rem;--space-md: 1rem;--space-lg: 1.5rem;--space-xl: 2rem;--space-2xl: 3rem;--radius-sm: .375rem;--radius-md: .5rem;--radius-lg: .75rem;--radius-full: 9999px;--shadow-sm: 0 1px 2px rgba(0, 0, 0, .05);--shadow-md: 0 4px 6px -1px rgba(0, 0, 0, .1);--shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, .1);--font-sans: "Roboto", system-ui, -apple-system, sans-serif;--font-mono: "JetBrains Mono", "Fira Code", monospace}[data-theme=dark]{--color-bg: #1e1e1e;--color-surface: #2a2a2a;--color-primary: #6366f1;--color-primary-hover: #818cf8;--color-text: #e4e4e7;--color-text-muted: #a1a1aa;--color-border: #3f3f46;--color-success: #4ade80;--color-warning: #fbbf24;--color-error: #f87171;--color-heading: #fbbf24;--color-heading-accent: #f87171;--color-tier-high: #4ade80;--color-tier-mid: #818cf8;--color-tier-low: #a1a1aa;--shadow-sm: 0 1px 2px rgba(0, 0, 0, .3);--shadow-md: 0 4px 6px -1px rgba(0, 0, 0, .4);--shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, .5)}*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}html{font-size:16px;-webkit-font-smoothing:antialiased}body{font-family:var(--font-sans);background:var(--color-bg);color:var(--color-text);line-height:1.6;min-height:100vh}a{color:var(--color-primary);text-decoration:none}a:hover{text-decoration:underline}button{cursor:pointer;font-family:inherit}.container{max-width:1200px;margin:0 auto;padding:0 var(--space-lg)}.visually-hidden{position:absolute;width:1px;height:1px;clip:rect(0 0 0 0);overflow:hidden}h1,h2,h3{color:var(--color-heading)}.theme-toggle{background:none;border:1px solid var(--color-border);border-radius:var(--radius-md);padding:.25rem .5rem;font-size:.8rem;cursor:pointer;color:var(--color-text-muted);transition:color .15s ease,border-color .15s ease;line-height:1}.theme-toggle:hover{color:var(--color-text);border-color:var(--color-text-muted)}.card{background:var(--color-surface);border-radius:var(--radius-lg);box-shadow:var(--shadow-sm);border:1px solid var(--color-border);padding:var(--space-lg);transition:box-shadow .3s ease,transform .3s ease;animation:cardFloat 6s ease-in-out infinite}.card:hover{box-shadow:var(--shadow-md);transform:translateY(-2px)}.card:nth-child(2n){animation-delay:-2s}.card:nth-child(3n){animation-delay:-4s}@keyframes cardFloat{0%,to{transform:translateY(0)}50%{transform:translateY(-3px)}}.card-header{display:flex;align-items:center;justify-content:space-between;margin-bottom:var(--space-md)}.card-title{font-size:1.125rem;font-weight:600;color:var(--color-heading)}.card-subtitle{font-size:.875rem;color:var(--color-text-muted)}.card-grid{display:grid;gap:var(--space-lg);grid-template-columns:repeat(auto-fill,minmax(min(280px,100%),1fr))}.card-grid--wide{grid-template-columns:1fr}@media (min-width: 768px){.card-grid--wide{grid-template-columns:2fr 1fr}}.nav{background:var(--color-surface);border-bottom:1px solid var(--color-border);padding:var(--space-md) var(--space-lg);display:flex;align-items:center;justify-content:space-between;position:sticky;top:0;z-index:100;flex-wrap:wrap}.nav-brand{font-size:1.25rem;font-weight:700;color:var(--color-primary)}.nav-hamburger{display:none;flex-direction:column;justify-content:center;gap:4px;background:none;border:none;padding:var(--space-sm);cursor:pointer;min-width:44px;min-height:44px}.nav-hamburger span{display:block;width:22px;height:2px;background:var(--color-text);border-radius:2px;transition:transform .2s ease,opacity .2s ease}.nav-hamburger--open span:nth-child(1){transform:translateY(6px) rotate(45deg)}.nav-hamburger--open span:nth-child(2){opacity:0}.nav-hamburger--open span:nth-child(3){transform:translateY(-6px) rotate(-45deg)}.nav-links{display:flex;align-items:center;gap:var(--space-md);list-style:none;margin:0;padding:0}.nav-links a:not(.btn),.nav-user{color:var(--color-text-muted);font-weight:500;font-size:.875rem;transition:color .15s ease}.nav-links a:not(.btn):hover{color:var(--color-primary);text-decoration:none}.nav-user{color:var(--color-text);font-weight:600;margin-right:var(--space-xs)}.btn{display:inline-flex;align-items:center;gap:var(--space-xs);padding:var(--space-sm) var(--space-md);border-radius:var(--radius-md);font-weight:500;font-size:.875rem;border:none;transition:background .15s ease}.btn-primary{background:var(--color-primary);color:#fff}.btn-primary:hover{background:var(--color-primary-hover)}.btn-secondary{background:transparent;color:var(--color-text);border:1px solid var(--color-border)}.btn-secondary:hover{background:var(--color-bg)}.badge{display:inline-flex;align-items:center;gap:var(--space-xs);padding:.125rem var(--space-sm);border-radius:var(--radius-full);font-size:.75rem;font-weight:600;text-transform:uppercase}.badge--high{background:#22c55e26;color:var(--color-tier-high)}.badge--mid{background:#6366f126;color:var(--color-tier-mid)}.badge--low{background:#94a3b826;color:var(--color-tier-low)}.avatar{display:inline-flex;align-items:center;justify-content:center;border-radius:var(--radius-full);background:var(--color-border);overflow:hidden;flex-shrink:0}.avatar--sm{width:32px;height:32px;font-size:.75rem}.avatar--md{width:48px;height:48px;font-size:1rem}.avatar--xl{width:96px;height:96px;font-size:2rem}.avatar-img{width:100%;height:100%;object-fit:cover}.avatar-initials{font-weight:700;color:var(--color-text-muted);text-transform:uppercase;-webkit-user-select:none;user-select:none}.input{width:100%;padding:var(--space-sm) var(--space-md);border:1px solid var(--color-border);border-radius:var(--radius-md);font-size:.875rem;font-family:inherit;background:var(--color-surface);color:var(--color-text);transition:border-color .15s ease}.input:focus{outline:none;border-color:var(--color-primary);box-shadow:0 0 0 3px #4f46e51a}.photo-modal-overlay{position:fixed;top:0;right:0;bottom:0;left:0;background:#000000b3;display:flex;align-items:center;justify-content:center;z-index:1000;animation:modalFadeIn .15s ease}@keyframes modalFadeIn{0%{opacity:0}to{opacity:1}}.photo-modal{position:relative;background:var(--color-surface);border-radius:var(--radius-lg);padding:var(--space-lg);box-shadow:var(--shadow-lg);max-width:400px;width:90%;text-align:center}.photo-modal-close{position:absolute;top:var(--space-sm);right:var(--space-sm);background:none;border:none;font-size:1.5rem;line-height:1;color:var(--color-text-muted);cursor:pointer;padding:var(--space-xs) var(--space-sm)}.photo-modal-close:hover{color:var(--color-text)}.photo-modal-img{width:200px;height:200px;border-radius:var(--radius-full);object-fit:cover;border:3px solid var(--color-border)}.photo-modal-name{margin-top:var(--space-md);font-weight:600;font-size:1.125rem;color:var(--color-text)}.avatar--clickable{cursor:pointer;border:none;padding:0;transition:box-shadow .15s ease,transform .15s ease}.avatar--clickable:hover{box-shadow:0 0 0 2px var(--color-primary);transform:scale(1.1)}.leaderboard-row{display:flex;align-items:center;padding:var(--space-sm) var(--space-md);border-bottom:1px solid var(--color-border);gap:var(--space-md)}.leaderboard-row:last-child{border-bottom:none}.leaderboard-row--current{background:#4f46e50f;border-left:3px solid var(--color-primary)}.leaderboard-rank{font-weight:700;min-width:2rem;text-align:center;color:var(--color-text-muted)}.leaderboard-name{flex:1;font-weight:500}.leaderboard-you{font-size:.7rem;font-weight:600;color:var(--color-primary);text-transform:uppercase;vertical-align:middle}.leaderboard-steps{font-weight:600;font-variant-numeric:tabular-nums}.stats-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(120px,1fr));gap:var(--space-md);padding:var(--space-md)}.stat-item{text-align:center}.stat-value{font-size:1.5rem;font-weight:700;color:var(--color-heading-accent);font-variant-numeric:tabular-nums}.stat-label{font-size:.75rem;font-weight:500;color:var(--color-text-muted);text-transform:uppercase;letter-spacing:.05em}.join-banner{display:flex;align-items:center;justify-content:space-between;padding:var(--space-md) var(--space-lg);background:linear-gradient(135deg,#4f46e514,#4f46e505);border:1px dashed var(--color-primary);border-radius:var(--radius-lg);margin-bottom:var(--space-lg);flex-wrap:wrap;gap:var(--space-sm)}.join-banner p{margin:0;font-weight:500}.join-banner .btn{white-space:nowrap}.step-history-row{display:flex;align-items:center;padding:var(--space-sm) var(--space-md);border-bottom:1px solid var(--color-border);gap:var(--space-md);flex-wrap:wrap}.step-history-row:last-child{border-bottom:none}.step-history-date{min-width:100px;font-weight:500;font-size:.875rem}.step-history-count{flex:1;font-weight:600;font-variant-numeric:tabular-nums;font-size:.875rem}.step-history-source{font-size:.7rem}.step-history-actions{display:flex;gap:var(--space-xs)}.btn-sm{padding:.2rem var(--space-sm);font-size:.75rem}.challenge-status{display:flex;align-items:center;gap:var(--space-sm);padding:var(--space-sm) var(--space-md);border-radius:var(--radius-md);font-size:.875rem;font-weight:500;margin-bottom:var(--space-md)}.challenge-status--upcoming{background:#f59e0b1a;color:#b45309;border:1px solid rgba(245,158,11,.3)}.challenge-status--active{background:#22c55e1a;color:#15803d;border:1px solid rgba(34,197,94,.3)}.challenge-status--ended{background:#94a3b81a;color:var(--color-text-muted);border:1px solid var(--color-border)}.challenge-selector{display:flex;align-items:center;gap:var(--space-md);margin-bottom:var(--space-lg);flex-wrap:wrap}.challenge-selector label{font-weight:600;font-size:.875rem;color:var(--color-text-muted)}.challenge-selector select{padding:var(--space-sm) var(--space-md);border:1px solid var(--color-border);border-radius:var(--radius-md);font-size:.875rem;font-family:inherit;background:var(--color-surface);color:var(--color-text);cursor:pointer;min-width:200px}.challenge-status{justify-content:space-between}.how-it-works-toggle{background:none;border:1px solid currentColor;border-radius:var(--radius-md);padding:.2rem var(--space-sm);font-size:.75rem;font-weight:600;cursor:pointer;color:inherit;white-space:nowrap;opacity:.8;transition:opacity .15s ease}.how-it-works-toggle:hover{opacity:1}.how-it-works-card{margin-bottom:var(--space-lg);animation:slideDown .2s ease}@keyframes slideDown{0%{opacity:0;transform:translateY(-8px)}to{opacity:1;transform:translateY(0)}}.how-it-works-close{background:none;border:none;font-size:1.25rem;cursor:pointer;color:var(--color-text-muted);padding:0 var(--space-xs);line-height:1}.how-it-works-close:hover{color:var(--color-text)}.how-it-works-section{margin-bottom:var(--space-md)}.how-it-works-section:last-child{margin-bottom:0}.how-it-works-section h4{font-size:.925rem;font-weight:600;margin-bottom:var(--space-xs)}.how-it-works-section p{font-size:.875rem;color:var(--color-text-muted);line-height:1.6;margin:0 0 var(--space-xs)}.how-it-works-tiers{list-style:none;padding:0;margin:var(--space-sm) 0}.how-it-works-tiers li{display:flex;align-items:center;gap:var(--space-sm);padding:var(--space-xs) 0;font-size:.875rem;color:var(--color-text-muted)}.how-it-works-tiers .badge{min-width:80px;justify-content:center}@media (max-width: 640px){.nav-hamburger{display:flex}.nav-links{display:none;flex-direction:column;width:100%;gap:var(--space-xs);padding-top:var(--space-md)}.nav-links--open{display:flex}.nav-links li{width:100%}.nav-links a:not(.btn),.nav-links .btn,.nav-links .theme-toggle{display:block;width:100%;text-align:center;padding:var(--space-sm) var(--space-md);min-height:44px;line-height:1.75}.btn{min-height:44px;padding:var(--space-sm) var(--space-md)}.btn-sm{min-height:44px;padding:var(--space-sm) var(--space-md);font-size:.8125rem}.leaderboard-row{flex-wrap:wrap}.step-history-date{min-width:auto}.challenge-selector select{min-width:0;width:100%}}