@import url("https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&display=swap");

:root{--blue:#236bd7;--blue-dark:#1555b3;--blue-soft:#eaf3ff;--ink:#17243c;--muted:#65748a;--line:#dce5f0;--bg:#f6f8fc;--white:#fff;--danger:#c13a49;--green:#19865a;--shadow:0 12px 32px rgba(28,59,98,.09)}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;min-width:320px;color:var(--ink);background:var(--bg);font-family:Inter,Arial,sans-serif}button,input,select,textarea{font:inherit}a{text-decoration:none;color:inherit}button{cursor:pointer}.container,.page{width:min(1100px,calc(100% - 36px));margin:auto}.page{padding:38px 0 70px;min-height:calc(100vh - 68px)}h1,h2,h3,p{margin-top:0}.site-header{height:68px;position:sticky;top:0;z-index:50;background:rgba(239,247,255,.97);border-bottom:1px solid #d6e4f4;backdrop-filter:blur(12px)}.header-inner{width:min(1180px,calc(100% - 32px));height:100%;margin:auto;display:flex;align-items:center;gap:32px}.brand{display:flex;align-items:center;gap:9px;color:#153d70;font-size:20px;font-weight:800}.brand span{width:36px;height:36px;display:grid;place-items:center;color:#fff;background:var(--blue);border-radius:9px}.header-menu{flex:1;display:flex;align-items:center;justify-content:space-between}.header-menu nav,.account-menu{display:flex;align-items:center;gap:20px}.header-menu nav a,.account-menu>a{color:#52637a;font-size:13px;font-weight:650}.header-menu a:hover,.header-menu a.active{color:var(--blue)}.user-chip{max-width:150px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;font-size:13px;font-weight:700}.menu-toggle{display:none;margin-left:auto;border:0;background:transparent;font-size:24px}.button{display:inline-flex;align-items:center;justify-content:center;gap:7px;padding:11px 18px;border:1px solid transparent;border-radius:9px;font-weight:700;transition:.2s}.button:hover{transform:translateY(-1px)}.button:disabled{opacity:.6;cursor:wait}.button-primary{color:#fff;background:var(--blue);box-shadow:0 6px 16px rgba(35,107,215,.2)}.button-primary:hover{background:var(--blue-dark)}.button-light{color:#2c4360;background:#fff;border-color:var(--line)}.button-danger{color:#b62c3c;background:#fff0f2;border-color:#ffd5db}.button-success{color:#fff;background:#1d9b67}.small{padding:8px 12px;font-size:12px}.large{padding:14px 22px}.button-row,.card-actions{display:flex;flex-wrap:wrap;gap:9px}.hero{min-height:480px;display:flex;align-items:center;background:linear-gradient(90deg,rgba(234,244,255,.98) 0%,rgba(239,247,255,.9) 48%,rgba(239,247,255,.12) 76%),url("../assets/images/banner.jpg") center/cover}.hero-content{max-width:620px;padding:75px 0}.eyebrow,.kicker{color:var(--blue);font-size:12px;font-weight:800;letter-spacing:1.4px}.hero h1{font-size:clamp(42px,6vw,66px);line-height:1.05;letter-spacing:-2.8px;margin:17px 0 22px}.hero h1 span{color:var(--blue)}.hero p{max-width:580px;color:#52647d;font-size:18px;line-height:1.7}.hero .button-row{margin-top:28px}.section{padding:60px 0}.section-heading{display:flex;align-items:end;justify-content:space-between;gap:20px;margin-bottom:23px}.section-heading h1,.section-heading h2{margin:7px 0 0}.features-grid,.sets-grid,.stats-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}.feature,.set-card,.panel,.stat-card{background:#fff;border:1px solid var(--line);border-radius:15px;box-shadow:0 4px 15px rgba(31,60,95,.04)}.feature{padding:25px}.feature-icon{width:45px;height:45px;display:grid;place-items:center;color:#fff;background:var(--blue);border-radius:11px}.feature h3{margin:17px 0 8px}.feature p,.set-card p{color:var(--muted);line-height:1.6;font-size:13px}.set-card{padding:20px;display:flex;flex-direction:column}.set-card-top,.set-meta{display:flex;align-items:center;justify-content:space-between;gap:12px}.pill{display:inline-flex;padding:5px 9px;color:#2464b4;background:var(--blue-soft);border-radius:18px;font-size:10px;font-weight:800;text-transform:uppercase}.study-count{color:var(--muted);font-size:11px}.set-card h3{margin:15px 0 8px;font-size:18px}.set-card p{flex:1;min-height:42px}.set-meta{padding:12px 0;margin:8px 0 14px;border-top:1px solid #edf1f6;border-bottom:1px solid #edf1f6;color:var(--muted);font-size:11px}.panel{padding:27px}.page-title{display:flex;align-items:center;justify-content:space-between;gap:22px;margin-bottom:30px}.page-title h1{font-size:34px;margin:7px 0}.page-title p{color:var(--muted);margin:0}.message{padding:12px 15px;margin:14px 0;border-radius:9px;font-size:13px}.message.error{color:#a42434;background:#ffedf0;border:1px solid #ffd1d8}.message.success{color:#16734a;background:#e9f8f1;border:1px solid #c8ead9}.hidden{display:none!important}.loading,.empty{padding:50px 20px;text-align:center;color:var(--muted);background:#fff;border:1px dashed #cbd7e6;border-radius:14px}.notice{padding:13px 17px;margin-bottom:18px;color:#225e9f;background:#e8f4ff;border:1px solid #cce4fb;border-radius:9px;font-size:13px}.site-footer{padding:30px;text-align:center;color:#7a8798;background:#eef3f9;border-top:1px solid var(--line);font-size:12px}label{display:grid;gap:7px;color:#34445b;font-size:13px;font-weight:700}input,select,textarea{width:100%;padding:12px 13px;color:var(--ink);background:#fff;border:1px solid #cbd7e5;border-radius:9px;outline:0}input:focus,select:focus,textarea:focus{border-color:#6da2ea;box-shadow:0 0 0 3px rgba(35,107,215,.1)}textarea{resize:vertical}.form-grid{display:grid;gap:18px}.two-columns{display:grid;grid-template-columns:1fr 1fr;gap:15px}.checkbox-label{display:flex;align-items:flex-start;gap:10px;padding:14px;border:1px solid var(--line);border-radius:9px}.checkbox-label input{width:18px}.checkbox-label span{display:grid;gap:3px}.checkbox-label small{color:var(--muted);font-weight:400}.modal-backdrop{position:fixed;inset:0;z-index:100;display:grid;place-items:center;padding:20px;background:rgba(14,28,48,.58)}.modal{width:min(620px,100%);max-height:calc(100vh - 40px);overflow:auto;background:#fff;border-radius:16px;box-shadow:0 25px 70px rgba(0,0,0,.25)}.modal-head{display:flex;align-items:center;justify-content:space-between;padding:19px 23px;border-bottom:1px solid var(--line)}.modal-head h2{margin:0}.modal-head button{border:0;background:transparent;font-size:24px}.modal form{padding:23px}.back-link{display:inline-block;margin-bottom:18px;color:var(--muted);font-size:13px}
@media(max-width:1180px){.menu-toggle{display:block}.header-menu{display:none;position:absolute;top:67px;left:0;right:0;max-height:calc(100vh - 67px);overflow:auto;padding:18px;background:#fff;border-bottom:1px solid var(--line);box-shadow:var(--shadow)}.header-menu.open,.header-menu nav,.account-menu{display:flex;flex-direction:column;align-items:stretch;gap:5px}.header-menu a,.account-menu span,.account-menu button{padding:10px}.features-grid,.sets-grid,.stats-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:620px){.page,.container{width:min(100% - 26px,1100px)}.hero{min-height:520px;background:linear-gradient(rgba(235,245,255,.96),rgba(235,245,255,.84)),url("../assets/images/banner.jpg") center/cover}.hero-content{text-align:center}.hero h1{font-size:43px}.hero .button-row{justify-content:center}.features-grid,.sets-grid,.stats-grid,.two-columns{grid-template-columns:1fr}.page-title,.section-heading{align-items:stretch;flex-direction:column}.set-meta{align-items:flex-start;flex-direction:column}}

/* Product UI refresh */
:root{--primary:#2563eb;--primary-dark:#1d4ed8;--primary-soft:#dbeafe;--bg:#f4f7fb;--card:#fff;--text:#0f172a;--muted:#64748b;--border:#e2e8f0;--success:#16a34a;--danger:#dc2626;--warning:#f59e0b;--radius:14px;--shadow:0 10px 30px rgba(15,23,42,.08);--ink:var(--text);--line:var(--border);--blue:var(--primary);--blue-dark:var(--primary-dark);--blue-soft:var(--primary-soft)}
body{color:var(--text);background:radial-gradient(circle at 0 0,rgba(37,99,235,.05),transparent 28rem),var(--bg);-webkit-font-smoothing:antialiased}
body.dark{--bg:#0b1220;--card:#111c2f;--text:#e5edf8;--ink:#e5edf8;--muted:#94a3b8;--border:#26354c;--line:#26354c;--primary-soft:#172b4d;background:#0b1220}
.site-header{height:72px;background:rgba(255,255,255,.9);border-color:rgba(226,232,240,.9);box-shadow:0 1px 0 rgba(15,23,42,.03)}body.dark .site-header{background:rgba(11,18,32,.9)}.header-inner{height:72px;gap:26px}.brand{color:var(--text);font-size:19px;letter-spacing:-.3px}.brand .brand-mark{width:38px;height:38px;color:#fff;background:linear-gradient(135deg,var(--primary),#60a5fa);border-radius:12px;box-shadow:0 8px 18px rgba(37,99,235,.25)}.header-menu nav{gap:4px}.header-menu nav a{padding:9px 11px;border-radius:9px;font-size:12px}.header-menu nav a:hover,.header-menu nav a.active{color:var(--primary);background:var(--primary-soft)}.account-menu{gap:9px}.user-avatar{width:34px;height:34px;display:grid;place-items:center;flex:none;color:#fff;background:linear-gradient(135deg,#2563eb,#7c3aed);border-radius:50%;font-size:13px;font-weight:800}.icon-button{width:38px;height:38px;display:grid;place-items:center;color:var(--text);background:var(--card);border:1px solid var(--border);border-radius:10px}
.button{min-height:42px;padding:10px 17px;border-radius:10px;box-shadow:none}.button-primary{background:linear-gradient(135deg,var(--primary),#3b82f6);box-shadow:0 8px 18px rgba(37,99,235,.18)}.button-light{color:var(--text);background:var(--card);border-color:var(--border)}.button-danger{color:var(--danger);background:#fff1f2;border-color:#fecdd3}.button-success{background:var(--success)}.small{min-height:36px;padding:8px 12px}.large{min-height:48px;padding:13px 21px}
input,select,textarea{min-height:44px;color:var(--text);background:var(--card);border-color:var(--border);border-radius:10px}input::placeholder,textarea::placeholder{color:#94a3b8}.panel,.feature,.set-card,.stat-card{background:var(--card);border-color:var(--border);border-radius:var(--radius)}.panel{box-shadow:var(--shadow)}
.hero{min-height:600px;background:none}.hero-grid{min-height:600px;display:grid;grid-template-columns:minmax(0,1.08fr) minmax(390px,.92fr);align-items:center;gap:64px}.hero-copy{padding:76px 0}.hero-copy h1{max-width:700px;margin:18px 0 22px;font-size:clamp(43px,6vw,68px);line-height:1.04;letter-spacing:-3.2px}.hero-copy h1 span{color:transparent;background:linear-gradient(100deg,#2563eb,#7c3aed);background-clip:text}.hero-copy p{max-width:640px;color:var(--muted);font-size:18px;line-height:1.75}.hero-trust{display:flex;flex-wrap:wrap;gap:18px;margin-top:28px;color:var(--muted);font-size:12px;font-weight:650}.hero-visual{position:relative;padding:44px}.hero-visual:before{content:"";position:absolute;inset:5% 0;background:linear-gradient(135deg,#dbeafe,#ede9fe);border-radius:40px;transform:rotate(-4deg)}.mockup-card{position:relative;min-height:390px;display:flex;flex-direction:column;align-items:center;justify-content:center;padding:40px;text-align:center;background:var(--card);border:1px solid rgba(255,255,255,.7);border-radius:26px;box-shadow:0 28px 70px rgba(37,99,235,.18)}.mockup-label{color:var(--primary);font-size:11px;font-weight:800;letter-spacing:1.5px}.mockup-card h2{margin:25px 0 8px;font-size:48px}.mockup-card p{color:var(--muted)}.mockup-meaning{width:100%;padding:18px;margin-top:24px;color:#166534;background:#ecfdf5;border-radius:13px}.floating-chip{position:absolute;z-index:2;padding:10px 14px;color:var(--text);background:var(--card);border:1px solid var(--border);border-radius:12px;box-shadow:var(--shadow);font-size:12px;font-weight:750}.chip-one{top:20px;right:8px}.chip-two{bottom:18px;left:4px}
.section{padding:72px 0}.section-soft{background:rgba(219,234,254,.28);border-block:1px solid rgba(226,232,240,.8)}.section-heading h2{font-size:clamp(27px,4vw,38px);letter-spacing:-1px}.features-grid.six{grid-template-columns:repeat(3,1fr)}.feature{padding:25px;transition:.2s}.feature:hover,.set-card:hover{transform:translateY(-4px);box-shadow:var(--shadow)}.feature-icon{width:48px;height:48px;color:var(--primary);background:var(--primary-soft);border-radius:13px;font-size:20px}
.set-card{position:relative;overflow:hidden;min-height:285px;padding:24px;box-shadow:0 4px 18px rgba(15,23,42,.04);transition:.2s}.set-card-accent{height:4px;position:absolute;inset:0 0 auto;background:linear-gradient(90deg,#2563eb,#8b5cf6)}.set-card h3{margin-top:19px;font-size:20px;line-height:1.35}.set-card p{min-height:62px}.set-meta{gap:10px;color:var(--muted)}.set-meta strong{color:var(--text)}.pill{color:#1d4ed8;background:var(--primary-soft);letter-spacing:.5px}
.state-card,.loading,.empty{grid-column:1/-1;min-height:190px;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:10px;padding:32px;color:var(--muted);background:var(--card);border:1px dashed var(--border);border-radius:var(--radius);text-align:center}.state-card strong{color:var(--text);font-size:16px}.state-card small{max-width:480px}.state-icon{width:42px;height:42px;display:grid;place-items:center;color:var(--primary);background:var(--primary-soft);border-radius:50%;font-weight:800}.spinner{width:28px;height:28px;border:3px solid var(--primary-soft);border-top-color:var(--primary);border-radius:50%;animation:spin .8s linear infinite}.error-state .state-icon{color:var(--danger);background:#fee2e2}@keyframes spin{to{transform:rotate(360deg)}}
.toast-container{position:fixed;z-index:1000;top:88px;right:20px;display:grid;gap:10px;width:min(390px,calc(100% - 32px))}.toast{display:grid;grid-template-columns:34px 1fr 28px;align-items:center;gap:10px;padding:13px 14px;color:var(--text);background:var(--card);border:1px solid var(--border);border-left:4px solid var(--primary);border-radius:12px;box-shadow:0 18px 45px rgba(15,23,42,.16);opacity:0;transform:translateX(20px);transition:.22s}.toast.show{opacity:1;transform:none}.toast-success{border-left-color:var(--success)}.toast-error{border-left-color:var(--danger)}.toast-warning{border-left-color:var(--warning)}.toast-icon{width:30px;height:30px;display:grid;place-items:center;color:#fff;background:var(--primary);border-radius:50%;font-weight:800}.toast-success .toast-icon{background:var(--success)}.toast-error .toast-icon{background:var(--danger)}.toast-warning .toast-icon{background:var(--warning)}.toast-close{color:var(--muted);background:transparent;border:0;font-size:20px}
body.dark .feature,body.dark .set-card,body.dark .panel,body.dark .state-card,body.dark .loading,body.dark .empty,body.dark .metric,body.dark .matching-board,body.dark .sentence-card,body.dark .flash-face,body.dark .auth-card,body.dark .table-wrap,body.dark .smart-stat,body.dark .game-result{background:var(--card);border-color:var(--border)}body.dark .header-menu{background:var(--card)}body.dark .button-danger{background:#3b1720}body.dark .mockup-meaning{color:#86efac;background:#123326}
@media(max-width:1000px){.hero-grid{grid-template-columns:1fr;gap:0;padding-bottom:55px}.hero-copy{padding:65px 0 25px}.hero-visual{width:min(620px,100%);margin:auto}.features-grid.six{grid-template-columns:repeat(2,1fr)}}
@media(max-width:768px){.header-menu{top:72px!important;left:12px!important;right:12px!important;border:1px solid var(--border);border-radius:14px}.header-menu nav{display:grid!important;grid-template-columns:1fr 1fr;gap:6px!important}.header-menu nav a{text-align:center}.account-menu{padding-top:12px;border-top:1px solid var(--border)}.features-grid.six{grid-template-columns:1fr}.page{padding-top:26px}}
@media(max-width:480px){.container,.page{width:min(100% - 24px,1100px)}.header-inner{width:calc(100% - 24px)}.brand>span:last-child{display:none}.hero-grid{min-height:auto}.hero-copy{padding-top:45px;text-align:left}.hero-copy h1{font-size:42px;letter-spacing:-2px}.hero-copy p{font-size:16px}.hero-visual{padding:22px 12px}.mockup-card{min-height:335px;padding:28px 20px}.mockup-card h2{font-size:39px}.floating-chip{display:none}.section{padding:52px 0}.button-row .button{width:100%}.toast-container{top:82px;right:12px}}