:root{--primary:#0ea347;--primary-dark:#087a35;--primary-light:#4ade80;--secondary:#22c55e;--dark:#0f172a;--dark-soft:#1e293b;--accent:#f59e0b;--danger:#f97316;--bg:#f8fafc;--bg-card:#fff;--text:#0f172a;--text-muted:#64748b;--border:#e2e8f0;--shadow:0 4px 6px -1px #00000012, 0 2px 4px -1px #0000000a;--shadow-lg:0 10px 15px -3px #0000001a, 0 4px 6px -2px #0000000d;--radius:12px;--radius-sm:8px;--bottom-nav-h:64px}*{box-sizing:border-box}html{-webkit-text-size-adjust:100%}body{background:var(--bg);color:var(--text);overscroll-behavior:none;min-height:100vh;margin:0;padding:0;font-family:Inter,system-ui,-apple-system,sans-serif}#root{flex-direction:column;min-height:100vh;display:flex}.sat-navbar{border-bottom:1px solid var(--border);z-index:200;height:60px;box-shadow:var(--shadow);background:#fff;align-items:center;padding:0 20px;display:flex;position:sticky;top:0}.navbar-inner{align-items:center;gap:24px;width:100%;max-width:1200px;margin:0 auto;display:flex}.brand{color:var(--primary);letter-spacing:-.5px;white-space:nowrap;flex-shrink:0;font-size:20px;font-weight:800;text-decoration:none}.brand span{color:var(--secondary)}.nav-links{flex:1;align-items:center;gap:2px;margin:0;padding:0;list-style:none;display:flex}.nav-links a{color:var(--text-muted);white-space:nowrap;border-radius:8px;align-items:center;gap:5px;padding:8px 12px;font-size:13.5px;font-weight:500;text-decoration:none;transition:all .2s;display:flex}.nav-links a:hover,.nav-links a.active{color:var(--primary);background:#0ea34714}.nav-avatar{color:#fff;cursor:pointer;background:linear-gradient(135deg,#0ea347,#087a35);border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;width:36px;height:36px;font-size:14px;font-weight:700;display:flex}.navbar-login-btn{color:#fff;cursor:pointer;white-space:nowrap;-webkit-tap-highlight-color:transparent;letter-spacing:.2px;background:linear-gradient(135deg,#0ea347,#087a35);border:none;border-radius:22px;align-items:center;gap:6px;padding:8px 18px;font-family:inherit;font-size:13.5px;font-weight:700;transition:all .2s;display:inline-flex;box-shadow:0 2px 10px #0ea34766}.navbar-login-btn:hover{transform:translateY(-1px);box-shadow:0 4px 16px #0ea34780}.navbar-login-btn:active{transform:translateY(0);box-shadow:0 2px 8px #0ea3474d}.bottom-nav{height:var(--bottom-nav-h);border-top:1px solid var(--border);z-index:150;padding-bottom:env(safe-area-inset-bottom);background:#fff;display:none;position:fixed;bottom:0;left:0;right:0;box-shadow:0 -4px 16px #00000014}.bottom-tab{color:var(--text-muted);flex-direction:column;flex:1;justify-content:center;align-items:center;gap:3px;padding:8px 4px;text-decoration:none;transition:color .2s;display:flex;position:relative}.bottom-tab.active{color:var(--primary)}.bottom-tab.active:before{content:"";background:var(--primary);border-radius:0 0 4px 4px;height:2px;position:absolute;top:0;left:20%;right:20%}.bottom-tab-icon{font-size:22px;line-height:1}.bottom-tab-label{letter-spacing:.2px;font-size:10px;font-weight:600}.hero-section{color:#fff;text-align:center;background:linear-gradient(135deg,#0ea347 0%,#087a35 50%,#065f26 100%);padding:64px 20px 56px;position:relative;overflow:hidden}.hero-section:before{content:"";background:url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");position:absolute;inset:0}.hero-badge{-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);background:#ffffff26;border:1px solid #ffffff40;border-radius:100px;align-items:center;gap:8px;margin-bottom:20px;padding:6px 14px;font-size:12px;font-weight:600;display:inline-flex}.hero-title{letter-spacing:-1.5px;margin-bottom:16px;font-size:clamp(30px,8vw,64px);font-weight:800;line-height:1.1}.hero-title .highlight{background:linear-gradient(90deg,#fbbf24,#f59e0b);-webkit-text-fill-color:transparent;-webkit-background-clip:text;background-clip:text}.hero-subtitle{opacity:.85;max-width:540px;margin:0 auto 28px;font-size:16px;line-height:1.6}.hero-buttons{flex-wrap:wrap;justify-content:center;gap:10px;display:flex}.stats-row{grid-template-columns:repeat(4,1fr);justify-content:center;gap:10px;max-width:600px;margin-top:40px;margin-left:auto;margin-right:auto;display:grid}.stat-card{border-radius:var(--radius);-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);text-align:center;background:#ffffff1f;border:1px solid #fff3;padding:14px 10px}.stat-card .number{letter-spacing:-.5px;font-size:22px;font-weight:800}.stat-card .label{opacity:.75;margin-top:2px;font-size:11px;font-weight:500}.feature-card{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);cursor:pointer;color:inherit;height:100%;padding:24px;text-decoration:none;transition:all .3s;display:block}.feature-card:hover{box-shadow:var(--shadow-lg);border-color:var(--primary-light);color:inherit;text-decoration:none;transform:translateY(-4px)}.feature-icon{border-radius:12px;justify-content:center;align-items:center;width:48px;height:48px;margin-bottom:14px;font-size:22px;display:flex}.icon-blue{background:#4f46e51a}.icon-green{background:#10b9811a}.icon-yellow{background:#f59e0b1a}.icon-red{background:#f973161a}.icon-purple{background:#8b5cf61a}.icon-cyan{background:#06b6d41a}.section{padding:48px 20px}.section-title{letter-spacing:-.8px;margin-bottom:8px;font-size:clamp(24px,5vw,32px);font-weight:800}.section-subtitle{color:var(--text-muted);margin-bottom:32px;font-size:15px}.question-card{border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);background:#fff;margin-bottom:16px;padding:24px}.question-number{background:var(--primary);color:#fff;border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;width:30px;height:30px;margin-bottom:14px;font-size:13px;font-weight:700;display:inline-flex}.option-btn{border:2px solid var(--border);border-radius:var(--radius-sm);cursor:pointer;text-align:left;width:100%;color:var(--text);box-sizing:border-box;background:#fff;align-items:flex-start;gap:10px;margin-bottom:10px;padding:13px 16px;font-family:inherit;font-size:14px;transition:all .2s;display:flex}.option-btn img{border-radius:6px;max-width:100%;margin-top:8px;display:block}.option-btn:active{transform:scale(.99)}.option-btn:hover{border-color:var(--primary);background:#0ea3470a}.option-btn.selected{border-color:var(--primary);color:var(--primary-dark);background:#0ea34714;font-weight:500}.option-btn.correct{border-color:var(--secondary);color:#065f46;background:#10b98114}.option-btn.incorrect{border-color:var(--danger);color:#9a3412;background:#f9731614}.option-letter{background:var(--bg);border:1px solid var(--border);border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;width:28px;height:28px;margin-top:1px;font-size:12px;font-weight:700;display:inline-flex}.progress-bar-custom{background:var(--border);border-radius:100px;height:7px;overflow:hidden}.progress-fill{background:linear-gradient(90deg, var(--primary), var(--primary-light));border-radius:100px;height:100%;transition:width .5s}.vocab-card{border:1px solid var(--border);border-radius:var(--radius);text-align:center;cursor:pointer;min-height:180px;box-shadow:var(--shadow);background:#fff;flex-direction:column;justify-content:center;align-items:center;padding:32px 20px;transition:all .3s;display:flex}.vocab-word{color:var(--primary);font-size:clamp(24px,7vw,36px);font-weight:800}.vocab-type{color:var(--text-muted);margin-top:4px;font-size:12px;font-style:italic}.vocab-definition{color:var(--text);margin-top:14px;font-size:15px;line-height:1.6}.flashcard-container{perspective:1000px;cursor:pointer;width:100%;max-width:480px;height:260px;margin:0 auto}.flashcard-inner{width:100%;height:100%;transform-style:preserve-3d;transition:transform .6s;position:relative}.flashcard-container.flipped .flashcard-inner{transform:rotateY(180deg)}.flashcard-front,.flashcard-back{border-radius:var(--radius);backface-visibility:hidden;text-align:center;box-shadow:var(--shadow-lg);flex-direction:column;justify-content:center;align-items:center;padding:28px 24px;display:flex;position:absolute;inset:0}.flashcard-front{background:linear-gradient(135deg, var(--primary), var(--dark));color:#fff}.flashcard-back{border:2px solid var(--primary);color:var(--text);background:#fff;transform:rotateY(180deg)}.roadmap-item{gap:16px;padding:16px 0;display:flex;position:relative}.roadmap-dot{z-index:1;border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;width:38px;height:38px;font-size:14px;display:flex;position:relative}.roadmap-dot.completed{background:var(--secondary);color:#fff}.roadmap-dot.active{background:var(--primary);color:#fff}.roadmap-dot.locked{background:var(--border);color:var(--text-muted)}.roadmap-line{background:var(--border);width:2px;position:absolute;top:54px;bottom:-16px;left:18px}.auth-container{background:linear-gradient(135deg,#f0faf4 0%,#e8f5ee 100%);justify-content:center;align-items:center;min-height:100vh;padding:20px;display:flex}.auth-card{width:100%;max-width:420px;box-shadow:var(--shadow-lg);border:1px solid var(--border);background:#fff;border-radius:20px;padding:36px 28px}.auth-card .logo{color:var(--primary);text-align:center;margin-bottom:6px;font-size:26px;font-weight:800}.form-control-custom{border:2px solid var(--border);border-radius:var(--radius-sm);-webkit-appearance:none;outline:none;width:100%;padding:12px 14px;font-family:inherit;font-size:15px;transition:border-color .2s}.form-control-custom:focus{border-color:var(--primary);box-shadow:0 0 0 3px #0ea3471f}.btn-primary-custom{background:linear-gradient(135deg, var(--primary), var(--primary-dark));color:#fff;border-radius:var(--radius-sm);cursor:pointer;-webkit-tap-highlight-color:transparent;touch-action:manipulation;border:none;align-items:center;gap:7px;padding:12px 22px;font-family:inherit;font-size:14px;font-weight:600;transition:all .2s;display:inline-flex;box-shadow:0 2px 12px #0ea3474d}.btn-primary-custom:hover{transform:translateY(-1px);box-shadow:0 8px 20px #0ea34766}.btn-primary-custom:active{transform:translateY(0)}.btn-outline-custom{color:var(--primary);border:2px solid var(--primary);border-radius:var(--radius-sm);cursor:pointer;-webkit-tap-highlight-color:transparent;touch-action:manipulation;background:0 0;align-items:center;gap:7px;padding:10px 20px;font-family:inherit;font-size:14px;font-weight:600;transition:all .2s;display:inline-flex}.btn-outline-custom:hover{background:var(--primary);color:#fff}.leaderboard-item{border-radius:var(--radius-sm);align-items:center;gap:12px;padding:12px 16px;transition:background .2s;display:flex}.leaderboard-item:hover{background:var(--bg)}.leaderboard-item.top-1{background:#f59e0b0f}.leaderboard-item.top-2{background:#94a3b80f}.leaderboard-item.top-3{background:#b453090f}.rank-badge{border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;width:34px;height:34px;font-size:13px;font-weight:700;display:flex}.rank-1{color:#fff;background:#fbbf24}.rank-2{color:#fff;background:#94a3b8}.rank-3{color:#fff;background:#cd7c2f}.rank-other{background:var(--bg);color:var(--text-muted);border:1px solid var(--border)}.timer-display{font-variant-numeric:tabular-nums;letter-spacing:-.5px;color:var(--primary);font-size:24px;font-weight:800}.timer-display.warning{color:var(--accent)}.timer-display.danger{color:var(--danger);animation:1s infinite pulse}@keyframes pulse{0%,to{opacity:1}50%{opacity:.5}}.sat-footer{color:#94a3b8;background:#0f172a;margin-top:auto;padding:40px 20px 20px}.footer-brand{color:#fff;margin-bottom:8px;font-size:20px;font-weight:800}.footer-link{color:#94a3b8;padding:4px 0;font-size:14px;text-decoration:none;transition:color .2s;display:block}.footer-link:hover{color:#fff}.badge-difficulty{border-radius:100px;align-items:center;padding:3px 9px;font-size:11px;font-weight:600;display:inline-flex}.badge-easy{color:#065f46;background:#10b9811a}.badge-medium{color:#92400e;background:#f59e0b1a}.badge-hard{color:#9a3412;background:#f973161a}.text-primary-custom{color:var(--primary)!important}.text-success-custom{color:var(--secondary)!important}.text-muted-custom{color:var(--text-muted)!important}.bg-primary-subtle{background:#0ea3470f!important}.card-hover{transition:all .3s}.card-hover:hover{box-shadow:var(--shadow-lg);transform:translateY(-3px)}@media (width<=900px){.stats-row{grid-template-columns:repeat(2,1fr);max-width:320px}}@media (width<=640px){.sidebar-desktop{display:none!important}.sidebar-main{margin-left:0!important}.desktop-only{display:none!important}.bottom-nav{display:flex}main{padding-bottom:var(--bottom-nav-h)}.sat-navbar{height:56px;padding:0 14px}.hero-section{padding:40px 16px 36px}.hero-subtitle{font-size:14px}.hero-buttons{gap:8px}.hero-buttons .btn-primary-custom,.hero-buttons .btn-outline-custom{padding:12px 18px;font-size:14px}.stats-row{grid-template-columns:repeat(2,1fr);gap:8px;max-width:100%;margin-top:28px}.stat-card{padding:12px 8px}.stat-card .number{font-size:18px}.stat-card .label{font-size:10px}.section{padding:28px 14px}.features-grid{grid-template-columns:1fr 1fr!important;gap:10px!important}.feature-card{padding:16px}.feature-icon{width:40px;height:40px;margin-bottom:10px;font-size:18px}.question-card{padding:18px 14px}.option-btn{padding:12px 14px;font-size:13px}.flashcard-container{height:220px}.auth-card{border-radius:16px;padding:28px 20px}.auth-container{align-items:flex-start;padding:40px 14px 14px}.sat-footer{padding-bottom:calc(20px + var(--bottom-nav-h))}.roadmap-dot{width:32px;height:32px;font-size:12px}.roadmap-line{left:15px}}@media (width<=380px){.hero-title{letter-spacing:-1px;font-size:26px}.features-grid{grid-template-columns:1fr!important}.stats-row{grid-template-columns:repeat(2,1fr)}}@supports (padding-bottom:env(safe-area-inset-bottom)){.bottom-nav{height:calc(var(--bottom-nav-h) + env(safe-area-inset-bottom));padding-bottom:env(safe-area-inset-bottom)}main{padding-bottom:calc(var(--bottom-nav-h) + env(safe-area-inset-bottom))}}