:root{--ink:#172033;--muted:#637083;--line:#dfe5ee;--paper:#fff;--soft:#f5f7fb;--navy:#12213f;--blue:#3067df;--blue2:#1f4db4;--danger:#bb3b45;--green:#24875d;--radius:18px;--shadow:0 12px 35px rgba(20,35,65,.09)}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:90px}body{margin:0;font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:var(--ink);background:var(--paper);line-height:1.55}button,select,textarea{font:inherit}button,a{touch-action:manipulation}.wrap{width:min(1160px,92%);margin:auto}
.site-header{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.96);backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}.nav-row{height:74px;display:flex;align-items:center;gap:28px}.brand{display:flex;align-items:center;gap:11px;color:var(--ink);text-decoration:none;font-weight:800;line-height:1.05}.brand small{display:block;font-size:.72rem;color:var(--muted);font-weight:700;margin-top:4px}.psi{width:42px;height:42px;border-radius:12px;display:grid;place-items:center;background:var(--navy);color:#fff;font-size:1.55rem}.nav-row nav{margin-left:auto;display:flex;gap:24px;align-items:center}.nav-row nav a{color:#364157;text-decoration:none;font-weight:700;font-size:.94rem}.nav-row nav a:hover{color:var(--blue)}.menu-btn{display:none;margin-left:auto;border:1px solid var(--line);background:#fff;border-radius:10px;padding:8px 12px}
.hero{padding:78px 0 66px;background:linear-gradient(140deg,#f7f9ff,#eef3ff)}.hero-grid{display:grid;grid-template-columns:1.25fr .75fr;gap:54px;align-items:center}.eyebrow{font-size:.78rem;font-weight:850;letter-spacing:.12em;color:var(--blue)}h1{font-size:clamp(2.6rem,5vw,4.7rem);line-height:1.03;letter-spacing:-.045em;margin:.5rem 0 1.2rem;max-width:850px}.lead{font-size:1.14rem;color:#556176;max-width:720px}.hero-actions{display:flex;gap:12px;flex-wrap:wrap;margin:28px 0 14px}.btn{border:0;border-radius:12px;padding:12px 18px;font-weight:800;cursor:pointer;text-decoration:none;display:inline-flex;align-items:center;justify-content:center}.primary{background:var(--blue);color:#fff}.primary:hover{background:var(--blue2)}.ghost{background:#fff;color:var(--ink);border:1px solid var(--line)}.danger{background:var(--danger);color:#fff}.fine{font-size:.83rem;color:#778296}.hero-card{background:#fff;border:1px solid #dbe4f4;border-radius:24px;padding:16px;box-shadow:var(--shadow);display:grid;grid-template-columns:1fr 1fr;gap:10px}.hero-stat{padding:20px;border-radius:16px;background:var(--soft)}.hero-stat strong{display:block;font-size:2rem;line-height:1}.hero-stat span{display:block;color:var(--muted);font-size:.85rem;margin-top:7px}
.exam-bar{background:var(--navy);color:#fff}.exam-bar-grid{display:grid;grid-template-columns:repeat(3,1fr)}.exam-bar-grid>div{padding:22px 24px;border-right:1px solid rgba(255,255,255,.12)}.exam-bar-grid strong,.exam-bar-grid span{display:block}.exam-bar-grid span{opacity:.75;font-size:.9rem;margin-top:3px}
.section{padding:76px 0}.soft{background:var(--soft)}.dark{background:var(--navy);color:#fff}.section-head{display:flex;justify-content:space-between;gap:50px;align-items:end;margin-bottom:30px}.section-head h2{font-size:clamp(2rem,4vw,3rem);line-height:1.08;letter-spacing:-.03em;margin:.35rem 0 0}.section-head>p{max-width:520px;color:var(--muted);margin:0}.light-head>p{color:#c6d0e3}.dark .eyebrow{color:#90b4ff}
.unit-tabs{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:25px}.unit-tabs button{border:1px solid var(--line);background:#fff;border-radius:999px;padding:8px 14px;font-weight:800;cursor:pointer}.unit-panel{border:1px solid var(--line);border-radius:var(--radius);padding:24px;margin:18px 0;background:#fff}.unit-heading{display:flex;align-items:center;gap:14px;flex-wrap:wrap;margin-bottom:18px}.unit-heading h3{font-size:1.45rem;margin:0}.unit-heading>span:last-child{margin-left:auto;color:var(--muted);font-size:.9rem}.unit-badge{background:#e9f0ff;color:var(--blue2);padding:5px 10px;border-radius:999px;font-size:.8rem;font-weight:800}.concept-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:10px}.concept{border:1px solid var(--line);border-radius:12px;background:#fbfcfe;padding:0 14px}.concept summary{cursor:pointer;font-weight:800;padding:13px 0}.concept p{color:var(--muted);margin:0 0 14px;font-size:.92rem}
.flash-toolbar{display:flex;gap:10px;align-items:center;flex-wrap:wrap;margin:20px 0}.flash-toolbar select,.flash-toolbar button,.flash-nav button{background:#fff;border:1px solid rgba(255,255,255,.25);border-radius:10px;padding:10px 13px;color:var(--ink);font-weight:700}.flash-toolbar span{margin-left:auto;color:#c6d0e3}.flashcard{width:min(760px,100%);min-height:330px;margin:22px auto;display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;background:#fff;border:0;border-radius:24px;padding:42px;box-shadow:0 24px 60px rgba(0,0,0,.22);cursor:pointer}.flashcard #flashLabel{font-size:.75rem;letter-spacing:.13em;color:var(--blue);font-weight:850}.flashcard strong{color:var(--ink);font-size:clamp(1.6rem,4vw,2.7rem);margin:12px 0}.flashcard p{color:var(--muted);font-size:1.05rem;max-width:650px}.flash-nav{display:flex;justify-content:center;gap:10px}
.test-grid{display:grid;grid-template-columns:repeat(5,1fr);gap:14px}.test-card{border:1px solid var(--line);border-radius:16px;padding:20px;box-shadow:0 8px 20px rgba(20,35,65,.05)}.test-card>span{font-size:.8rem;font-weight:850;color:var(--blue)}.test-card h3{font-size:1.4rem;margin:.45rem 0}.test-card p{color:var(--muted);font-size:.9rem}.test-card .btn{width:100%;margin-top:8px}.hidden{display:none!important}
.test-app{margin-top:24px}.test-top{display:flex;justify-content:space-between;align-items:center;gap:20px;border-bottom:1px solid var(--line);padding-bottom:15px}.test-top h3{margin:4px 0 0}.text-btn{border:0;background:transparent;color:var(--blue);font-weight:800;cursor:pointer;padding:0}.timer{font-variant-numeric:tabular-nums;background:var(--navy);color:#fff;border-radius:12px;padding:10px 16px;font-size:1.25rem;font-weight:850}.timer.warning{background:var(--danger)}.progress-row{display:flex;align-items:center;gap:14px;margin:14px 0}.progress{height:8px;background:#e8edf5;border-radius:999px;flex:1;overflow:hidden}.progress span{display:block;height:100%;background:var(--blue);width:0}.progress-row>span{font-size:.85rem;color:var(--muted)}.test-layout{display:grid;grid-template-columns:230px 1fr;gap:20px}.navigator{border:1px solid var(--line);border-radius:14px;padding:14px;align-self:start;position:sticky;top:95px}.navigator h4{margin:0 0 10px}.q-nav{display:grid;grid-template-columns:repeat(5,1fr);gap:5px}.q-nav button{aspect-ratio:1;border:1px solid var(--line);background:#fff;border-radius:7px;cursor:pointer;font-size:.78rem}.q-nav button.current{outline:2px solid var(--blue)}.q-nav button.answered{background:#e5f5ee;border-color:#b6decf}.q-nav button.flagged::after{content:"•";color:#d09000}.nav-key{font-size:.75rem;color:var(--muted);display:grid;gap:4px;margin-top:12px}.answered-dot{display:inline-block;width:9px;height:9px;border-radius:50%;background:#b6decf}.question-card{border:1px solid var(--line);border-radius:16px;padding:26px;min-height:450px}.q-meta{display:flex;justify-content:space-between;color:var(--muted);font-size:.85rem}.question-card h3{font-size:1.25rem;line-height:1.45;margin:22px 0}.choices{display:grid;gap:10px}.choice{width:100%;text-align:left;border:1px solid var(--line);background:#fff;border-radius:12px;padding:14px;cursor:pointer;display:flex;gap:10px}.choice:hover{border-color:#9ab6ee}.choice.selected{border-color:var(--blue);background:#eef4ff}.choice b{min-width:22px}.q-actions{display:flex;justify-content:space-between;gap:10px;margin-top:26px}.q-actions button{border:1px solid var(--line);background:#fff;border-radius:10px;padding:10px 14px;font-weight:750;cursor:pointer}.submit-row{text-align:right;margin-top:15px}.results{margin-top:25px;border:1px solid var(--line);border-radius:18px;padding:24px}.score-big{font-size:3rem;font-weight:900;letter-spacing:-.04em}.review-list{display:grid;gap:10px;margin-top:20px}.review-item{border:1px solid var(--line);border-radius:12px;padding:15px}.review-item.correct{border-left:5px solid var(--green)}.review-item.wrong{border-left:5px solid var(--danger)}.review-item p{margin:.45rem 0;color:var(--muted)}
.frq-types{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin-bottom:24px}.frq-types>div{background:#fff;border:1px solid var(--line);border-radius:14px;padding:18px}.frq-types strong,.frq-types span{display:block}.frq-types strong{color:var(--blue);font-size:1.35rem}.frq-types span{color:var(--muted);margin-top:6px}.frq-list{display:grid;grid-template-columns:repeat(2,1fr);gap:12px}.frq-item{background:#fff;border:1px solid var(--line);border-radius:14px;padding:18px;display:flex;align-items:center;gap:14px}.frq-tag{background:#e9f0ff;color:var(--blue2);font-weight:850;border-radius:999px;padding:5px 9px;font-size:.78rem}.frq-item h3{margin:0;font-size:1rem;flex:1}.frq-item button{border:0;background:var(--blue);color:#fff;border-radius:9px;padding:8px 12px;font-weight:800;cursor:pointer}.frq-app{background:#fff;border:1px solid var(--line);border-radius:18px;padding:24px}.frq-app-top{display:flex;justify-content:space-between;gap:20px;align-items:center}.source-box{background:#f7f9fc;border:1px solid var(--line);border-radius:12px;padding:16px;margin:16px 0;white-space:pre-line}.frq-parts{padding-left:22px}.frq-app textarea{width:100%;min-height:420px;border:1px solid var(--line);border-radius:12px;padding:15px;resize:vertical}.frq-controls{display:flex;gap:10px;justify-content:flex-end;margin-top:10px}.frq-controls button{border:1px solid var(--line);background:#fff;border-radius:10px;padding:10px 14px;font-weight:800;cursor:pointer}.guide-box{background:#eef7f2;border:1px solid #c6e4d4;border-radius:12px;padding:16px;margin-top:16px}.info-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}.info-grid article{border:1px solid var(--line);border-radius:16px;padding:20px}.info-grid h3{margin-top:0}.info-grid strong{color:var(--blue)}.info-grid p{color:var(--muted)}.strategy{margin-top:18px;border:1px solid var(--line);border-radius:16px;padding:20px}.strategy li{margin:8px 0;color:#505c70}
footer{border-top:1px solid var(--line);padding:30px 0;background:#fbfcfe}.footer-row{display:flex;justify-content:space-between;align-items:center;gap:40px}.footer-row p{max-width:640px;color:var(--muted);font-size:.85rem}
@media(max-width:900px){.hero-grid,.section-head,.test-layout{grid-template-columns:1fr;display:grid}.concept-grid{grid-template-columns:1fr 1fr}.test-grid{grid-template-columns:1fr 1fr}.navigator{position:static}.info-grid{grid-template-columns:1fr}.exam-bar-grid{grid-template-columns:1fr}.exam-bar-grid>div{border-right:0;border-bottom:1px solid rgba(255,255,255,.12)}}
@media(max-width:700px){.nav-row nav{display:none;position:absolute;left:0;right:0;top:74px;background:#fff;padding:16px 4%;border-bottom:1px solid var(--line);flex-direction:column;align-items:stretch}.nav-row nav.open{display:flex}.menu-btn{display:block}.hero{padding:50px 0}.hero-card,.concept-grid,.test-grid,.frq-list,.frq-types{grid-template-columns:1fr}.section{padding:55px 0}.unit-heading>span:last-child{margin-left:0}.question-card{padding:18px}.test-layout{display:flex;flex-direction:column}.navigator{order:2}.q-nav{grid-template-columns:repeat(10,1fr)}.flashcard{min-height:280px;padding:28px}.footer-row{flex-direction:column;align-items:flex-start}}