:root{--blue:#1e3a8a;--blue-mid:#2563eb;--blue-light:#dbeafe;--purple:#7c3aed;--purple-light:#ede9fe;--green:#059669;--green-light:#d1fae5;--amber:#d97706;--amber-light:#fef3c7;--red:#dc2626;--red-light:#fee2e2;--gray:#f8fafc;--gray2:#f1f5f9;--gray3:#e2e8f0;--white:#fff;--text:#0f172a;--text2:#475569;--text3:#94a3b8;--r:12px;--nav-h:56px}*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;background:var(--gray);color:var(--text);font-size:15px;line-height:1.6}a{color:inherit;text-decoration:none}button,input,select,textarea{font-family:inherit}.app-nav{background:#fff;border-bottom:1px solid var(--gray3);padding:0 20px;display:flex;align-items:center;justify-content:space-between;height:var(--nav-h);position:sticky;top:0;z-index:100;gap:12px}.nav-logo{font-size:20px;font-weight:800;background:linear-gradient(135deg,var(--blue),var(--purple));-webkit-background-clip:text;-webkit-text-fill-color:transparent;white-space:nowrap}.nav-tabs{display:flex;gap:2px;overflow-x:auto}.nav-tab{padding:5px 11px;border-radius:6px;font-size:13px;font-weight:500;border:none;background:none;color:var(--text2);cursor:pointer;white-space:nowrap}.nav-tab:hover{background:var(--gray2)}.nav-tab.active{background:var(--blue-light);color:var(--blue)}.nav-right{display:flex;align-items:center;gap:8px;flex-shrink:0}.avatar{width:32px;height:32px;border-radius:50%;background:linear-gradient(135deg,var(--blue-mid),var(--purple));display:flex;align-items:center;justify-content:center;color:#fff;font-size:12px;font-weight:700;cursor:pointer;border:none}.streak-badge{background:var(--amber-light);color:var(--amber);font-size:12px;font-weight:600;padding:3px 10px;border-radius:20px}.page-content{padding:20px 24px 80px;max-width:1100px;margin:0 auto}@media (max-width:600px){.page-content{padding:14px 14px 80px}.nav-tabs{display:none}}.mobile-bottom-nav{display:none;position:fixed;bottom:0;left:0;right:0;background:#fff;border-top:1px solid var(--gray3);z-index:200;padding:6px 0 10px}.mob-tab{display:flex;flex-direction:column;align-items:center;gap:2px;font-size:10px;color:var(--text3);background:none;border:none;cursor:pointer;padding:4px 10px;font-weight:500}.mob-tab.active{color:var(--blue)}.mob-tab span:first-child{font-size:18px}@media (max-width:600px){.mobile-bottom-nav{display:flex;justify-content:space-around}}.grid2{display:grid;grid-template-columns:repeat(2,1fr);gap:16px}.grid3{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.grid4{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}@media (max-width:700px){.grid3,.grid4{grid-template-columns:repeat(2,1fr)}}@media (max-width:480px){.grid2,.grid3,.grid4{grid-template-columns:1fr}}.card{background:#fff;border-radius:var(--r);border:1px solid var(--gray3);padding:18px}.card-title{font-size:11px;font-weight:700;color:var(--text3);text-transform:uppercase;letter-spacing:1px;margin-bottom:4px}.card-value{font-size:26px;font-weight:700}.card-sub{font-size:12px;color:var(--text3);margin-top:2px}.section-header{display:flex;align-items:center;justify-content:space-between;margin-bottom:16px}.section-title{font-size:18px;font-weight:700}.chip{display:inline-flex;align-items:center;gap:4px;padding:3px 10px;border-radius:20px;font-size:12px;font-weight:600}.chip-blue{background:var(--blue-light);color:var(--blue)}.chip-green{background:var(--green-light);color:var(--green)}.chip-red{background:var(--red-light);color:var(--red)}.chip-purple{background:var(--purple-light);color:var(--purple)}.chip-amber{background:var(--amber-light);color:var(--amber)}.prog-bar{background:var(--gray3);border-radius:99px;height:8px;overflow:hidden;margin-top:6px}.prog-fill{height:100%;border-radius:99px;transition:width .8s}.prog-blue{background:linear-gradient(90deg,var(--blue-mid),var(--purple))}.prog-green{background:var(--green)}.prog-amber{background:var(--amber)}.prog-red{background:var(--red)}.btn{padding:9px 18px;border-radius:8px;border:none;font-weight:600;font-size:14px;cursor:pointer;transition:all .15s;display:inline-flex;align-items:center;gap:6px}.btn:hover{transform:translateY(-1px)}.btn:disabled{opacity:.5;cursor:not-allowed;transform:none}.btn-blue{background:var(--blue);color:#fff}.btn-green{background:var(--green);color:#fff}.btn-red{background:var(--red);color:#fff}.btn-purple{background:var(--purple);color:#fff}.btn-outline{background:#fff;color:var(--text);border:1.5px solid var(--gray3)}.btn-sm{padding:6px 13px;font-size:13px}.btn-full{width:100%;justify-content:center}.form-group{margin-bottom:16px}.form-label{font-size:13px;font-weight:600;color:var(--text2);margin-bottom:5px;display:block}.form-input{width:100%;padding:10px 13px;border:1.5px solid var(--gray3);border-radius:8px;font-size:14px;outline:none;transition:border-color .15s;background:#fff;color:var(--text)}.form-input:focus{border-color:var(--blue-mid)}.form-select{width:100%;padding:10px 13px;border:1.5px solid var(--gray3);border-radius:8px;font-size:14px;outline:none;background:#fff;color:var(--text)}.optional-tag{font-size:11px;color:var(--text3);font-weight:400;margin-left:4px}.auth-page{min-height:100vh;background:linear-gradient(135deg,var(--blue),var(--purple));display:flex;align-items:center;justify-content:center;padding:20px}.auth-card{background:#fff;border-radius:20px;padding:36px;width:100%;max-width:520px;box-shadow:0 20px 60px #00000026}.auth-logo{font-size:26px;font-weight:800;background:linear-gradient(135deg,var(--blue),var(--purple));-webkit-background-clip:text;-webkit-text-fill-color:transparent;margin-bottom:6px}.motiv-card{background:linear-gradient(135deg,var(--blue),var(--purple));color:#fff;border-radius:14px;padding:20px;margin-bottom:20px}.motiv-quote{font-size:16px;font-weight:500;line-height:1.6;margin-bottom:6px}.countdown-bar{background:#fff;border-radius:var(--r);padding:16px 22px;display:flex;align-items:center;justify-content:space-between;margin-bottom:20px;border:1px solid var(--gray3);flex-wrap:wrap;gap:12px}.countdown-main{font-size:22px;font-weight:800;color:var(--red)}.countdown-units{display:flex;gap:8px}.c-unit{text-align:center;background:var(--blue-light);border-radius:8px;padding:7px 12px}.c-unit-num{font-size:20px;font-weight:700;color:var(--blue);display:block;font-variant-numeric:tabular-nums}.c-unit-lbl{font-size:9px;color:var(--text2);text-transform:uppercase;letter-spacing:1px}.quiz-q{font-size:15px;font-weight:500;line-height:1.6;margin-bottom:16px}.quiz-opt{display:flex;align-items:flex-start;gap:12px;padding:11px 14px;border:1.5px solid var(--gray3);border-radius:10px;cursor:pointer;margin-bottom:8px;transition:all .15s;font-size:14px;line-height:1.5}.quiz-opt:hover:not(.locked){border-color:var(--blue-mid);background:var(--blue-light)}.quiz-opt.selected{border-color:var(--blue-mid);background:var(--blue-light)}.quiz-opt.correct{border-color:var(--green);background:var(--green-light);color:var(--green)}.quiz-opt.wrong{border-color:var(--red);background:var(--red-light);color:var(--red)}.quiz-opt.locked{pointer-events:none}.opt-key{width:26px;height:26px;border-radius:50%;border:1.5px solid currentColor;display:flex;align-items:center;justify-content:center;font-size:12px;font-weight:700;flex-shrink:0;margin-top:1px}.test-header{background:var(--blue);color:#fff;border-radius:var(--r) var(--r) 0 0;padding:12px 20px;display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:8px}.test-timer{font-size:20px;font-weight:700;font-variant-numeric:tabular-nums}.q-nav{display:flex;flex-wrap:wrap;gap:5px;margin-top:16px;padding-top:16px;border-top:1px solid var(--gray3)}.q-num{width:30px;height:30px;border-radius:6px;border:1.5px solid var(--gray3);display:flex;align-items:center;justify-content:center;font-size:11px;font-weight:700;cursor:pointer}.q-num.answered{background:var(--green);border-color:var(--green);color:#fff}.q-num.marked{background:var(--amber);border-color:var(--amber);color:#fff}.q-num.current{border-color:var(--blue);color:var(--blue)}.flashcard{perspective:1000px;cursor:pointer;height:190px;transition:transform .2s}.flashcard:hover{transform:translateY(-3px)}.flashcard-inner{position:relative;width:100%;height:100%;transition:transform .5s cubic-bezier(.4,.2,.2,1);transform-style:preserve-3d}.flashcard.flipped .flashcard-inner{transform:rotateY(180deg)}.fc-face{position:absolute;width:100%;height:100%;backface-visibility:hidden;border-radius:16px;display:flex;flex-direction:column;align-items:center;justify-content:center;padding:22px;text-align:center;box-shadow:0 4px 16px #00000014}.fc-front{background:linear-gradient(150deg,var(--blue) 0%,var(--purple) 100%);color:#fff}.fc-back{background:linear-gradient(150deg,var(--green) 0%,#0d9488 100%);color:#fff;transform:rotateY(180deg)}.formula-card{background:#fff;border:1px solid var(--gray3);border-radius:16px;padding:18px;position:relative;overflow:hidden;transition:transform .2s,box-shadow .2s}.formula-card:before{content:"";position:absolute;top:0;left:0;right:0;height:4px;background:linear-gradient(90deg,var(--blue-mid),var(--purple))}.formula-card:hover{transform:translateY(-3px);box-shadow:0 10px 24px #00000014}.formula-eq{background:linear-gradient(135deg,var(--blue-light),#eef2ff);border-radius:10px;padding:12px;font-family:Courier New,monospace;font-size:18px;text-align:center;color:var(--blue);font-weight:700;margin:10px 0;letter-spacing:.3px}.rank-meter{background:linear-gradient(90deg,#dc2626,#d97706,#059669 66%,#2563eb);height:10px;border-radius:99px;position:relative;margin:10px 0}.rank-needle{position:absolute;top:-4px;width:3px;height:18px;background:var(--text);border-radius:2px;transition:left .8s}.xp-bar-wrap{background:var(--gray3);border-radius:99px;height:8px;overflow:hidden;margin-top:6px}.xp-bar{height:100%;border-radius:99px;background:linear-gradient(90deg,#f59e0b,#ef4444)}.subj-row{display:flex;justify-content:space-between;font-size:13px;font-weight:500;margin-bottom:4px}.insight{border-left:3px solid;padding:10px 14px;border-radius:0 8px 8px 0;margin-bottom:8px}.loading-screen{min-height:100vh;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:14px}.spinner{width:36px;height:36px;border:3px solid var(--gray3);border-top-color:var(--blue);border-radius:50%;animation:spin .7s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.mb-3{margin-bottom:12px}.mb-4{margin-bottom:16px}.mb-5{margin-bottom:20px}.mb-6{margin-bottom:24px}.mt-4{margin-top:16px}.mt-5{margin-top:20px}.chip-row{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:14px}.text-center{text-align:center}.pyq-badge{background:var(--amber-light);color:var(--amber);font-size:11px;font-weight:700;padding:2px 8px;border-radius:20px}.repeat-badge{background:var(--red-light);color:var(--red);font-size:11px;font-weight:700;padding:2px 8px;border-radius:20px}.solved-badge{background:var(--green-light);color:var(--green);font-size:11px;font-weight:700;padding:2px 8px;border-radius:20px}.content-hero{border-radius:18px;padding:28px 26px;margin-bottom:22px;color:#fff;position:relative;overflow:hidden}.content-hero:after{content:"";position:absolute;top:0;right:0;bottom:0;left:0;background:radial-gradient(circle at 85% 20%,rgba(255,255,255,.18),transparent 60%)}.content-hero-bio{background:linear-gradient(135deg,#059669,#10b981)}.content-hero-phy{background:linear-gradient(135deg,#1e3a8a,#2563eb)}.content-hero-chem{background:linear-gradient(135deg,#7c3aed,#a855f7)}.content-hero-title{font-size:24px;font-weight:800;position:relative;z-index:1}.content-hero-sub{font-size:13px;opacity:.85;margin-top:4px;position:relative;z-index:1;max-width:480px}.content-hero-stats{display:flex;gap:22px;margin-top:16px;position:relative;z-index:1;flex-wrap:wrap}.content-hero-stat-num{font-size:20px;font-weight:800}.content-hero-stat-lbl{font-size:11px;opacity:.8;text-transform:uppercase;letter-spacing:.5px}.chip-filter-row{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:20px}.chip-filter{cursor:pointer;padding:6px 14px;border-radius:20px;font-size:12.5px;font-weight:600;border:1.5px solid var(--gray3);background:#fff;color:var(--text2);transition:all .15s;white-space:nowrap}.chip-filter:hover{border-color:var(--blue-mid)}.chip-filter.active{border-color:transparent;color:#fff}.search-box{position:relative;margin-bottom:18px;max-width:420px}.search-box input{width:100%;padding:11px 14px 11px 38px;border:1.5px solid var(--gray3);border-radius:12px;font-size:14px;outline:none;background:#fff;transition:border-color .15s}.search-box input:focus{border-color:var(--blue-mid)}.search-box svg{position:absolute;left:13px;top:50%;transform:translateY(-50%);color:var(--text3);pointer-events:none}.flip-scene{perspective:1200px}.flip-card{position:relative;width:100%;min-height:172px;cursor:pointer}.flip-card-inner{position:relative;width:100%;height:100%;min-height:172px;transition:transform .5s cubic-bezier(.4,.2,.2,1);transform-style:preserve-3d}.flip-card.flipped .flip-card-inner{transform:rotateY(180deg)}.flip-card-face{position:absolute;top:0;right:0;bottom:0;left:0;backface-visibility:hidden;border-radius:16px;padding:20px;display:flex;flex-direction:column;justify-content:center;box-shadow:0 2px 10px #0000000d}.flip-card-front{background:#fff;border:1.5px solid var(--gray3)}.flip-card-front:hover{border-color:var(--green);box-shadow:0 6px 20px #0596691a}.flip-card-back{background:linear-gradient(135deg,var(--green),#10b981);color:#fff;transform:rotateY(180deg)}.flip-tag{font-size:10px;font-weight:700;text-transform:uppercase;letter-spacing:1px;opacity:.6;margin-bottom:10px}.flip-text{font-size:14.5px;font-weight:600;line-height:1.55}.flip-card-back .flip-text{font-weight:500}.flip-hint{position:absolute;bottom:12px;right:16px;font-size:10.5px;opacity:.55}.eq-card{background:#fff;border:1.5px solid var(--gray3);border-radius:16px;padding:18px;transition:all .2s;position:relative}.eq-card:hover{border-color:var(--blue-mid);box-shadow:0 6px 20px #2563eb14;transform:translateY(-2px)}.eq-card-tag{display:inline-block;font-size:10px;font-weight:700;text-transform:uppercase;letter-spacing:.8px;padding:3px 9px;border-radius:20px;margin-bottom:10px}.eq-card-title{font-size:14.5px;font-weight:700;margin-bottom:10px;padding-right:20px}.eq-box{border-radius:10px;padding:14px;font-family:Courier New,monospace;font-size:15px;text-align:center;font-weight:700;margin-bottom:10px;letter-spacing:.3px;line-height:1.5}.eq-notes{font-size:12.5px;color:var(--text2);line-height:1.55}.bookmark-btn{position:absolute;top:14px;right:14px;background:none;border:none;font-size:16px;cursor:pointer;opacity:.45;transition:opacity .15s}.bookmark-btn:hover,.bookmark-btn.active{opacity:1}.empty-state{text-align:center;padding:50px 20px;color:var(--text3)}.empty-state-icon{font-size:36px;margin-bottom:10px}
