:root{--color-primary:#00A0EB;--color-primary-light:#91D6F2;--color-primary-lighter:#C3E7F4;--color-primary-dark:#004960;--color-primary-darker:#002733;--color-accent:#2D459A;--color-accent-dark:#1E3275;--color-warm:#ECC2AD;--color-bg:#F7F8FA;--color-bg-card:#FFFFFF;--color-bg-alt:#EFEFEF;--color-bg-dark:#002733;--color-text:#231815;--color-text-light:#5A5552;--color-text-muted:#8A8785;--color-border:#E0E3E8;--color-border-light:#ECEEF2;--color-warn-bg:#FEF7E6;--color-warn-border:#F5C26B;--color-warn-text:#8C6A1F;--font-sans:"Inter",-apple-system,"Alibaba PuHuiTi","PingFang SC","Microsoft YaHei",sans-serif;--text-xs:0.75rem;--text-sm:0.875rem;--text-base:1rem;--text-lg:1.125rem;--text-xl:1.25rem;--text-2xl:1.5rem;--text-3xl:2rem;--space-xs:0.25rem;--space-sm:0.5rem;--space-md:1rem;--space-lg:1.5rem;--space-xl:2rem;--space-2xl:3rem;--space-3xl:4rem;--radius-sm:4px;--radius-md:8px;--radius-lg:12px;--radius-xl:16px;--radius-full:9999px;--shadow-sm:0 1px 2px rgba(0,39,51,0.04),0 2px 8px rgba(0,39,51,0.04);--shadow-md:0 4px 12px rgba(0,39,51,0.06),0 12px 32px rgba(0,39,51,0.08);--shadow-lg:0 12px 32px rgba(0,39,51,0.08),0 32px 80px rgba(0,39,51,0.12);--shadow-glow:0 0 0 4px rgba(0,160,235,0.10);--gradient-bg:linear-gradient(180deg,#FAFCFE,#F2F6FA);--gradient-card:linear-gradient(180deg,#FFFFFF,#FAFCFE);--gradient-ai:linear-gradient(135deg,#DDEEF7,#C3E7F4);--gradient-user:linear-gradient(180deg,#FFFFFF,#F8FAFC);--gradient-primary:linear-gradient(135deg,#00A0EB,#2D459A);--gradient-orb:radial-gradient(circle at 30% 30%,#6FC8F2 0%,#00A0EB 50%,#004960 100%);--transition-fast:0.15s cubic-bezier(0.16,1,0.3,1);--transition-base:0.25s cubic-bezier(0.16,1,0.3,1);--transition-spring:0.4s cubic-bezier(0.34,1.56,0.64,1);--z-base:1;--z-dropdown:100;--z-sticky:200;--z-overlay:300;--z-modal:400}*,:after,:before{box-sizing:border-box}body,html{margin:0;padding:0;background:var(--gradient-bg);background-attachment:fixed;color:var(--color-text);font-family:var(--font-sans);font-size:var(--text-sm);line-height:1.6;letter-spacing:-.005em;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;text-rendering:optimizeLegibility}h1,h2,h3{letter-spacing:-.02em;font-feature-settings:"ss01","cv01"}a{color:var(--color-primary);text-decoration:none;transition:color var(--transition-fast)}a:hover{color:var(--color-primary-dark)}button{cursor:pointer;padding:var(--space-sm) var(--space-md);border:none;border-radius:var(--radius-md);background:var(--gradient-primary);color:#fff;font-size:var(--text-sm);font-weight:500;font-family:inherit;letter-spacing:-.005em;transition:transform var(--transition-fast),box-shadow var(--transition-base),opacity var(--transition-fast);box-shadow:0 1px 2px rgba(0,73,96,.12),inset 0 1px 0 rgba(255,255,255,.15)}button:hover{transform:translateY(-1px);box-shadow:0 4px 12px rgba(0,73,96,.18),inset 0 1px 0 rgba(255,255,255,.2)}button:active{transform:translateY(0)}button:disabled{background:var(--color-bg-alt);color:var(--color-text-muted);cursor:not-allowed;box-shadow:none;transform:none}input,select,textarea{width:100%;padding:var(--space-sm) var(--space-md);border:1px solid var(--color-border);border-radius:var(--radius-md);font-size:var(--text-sm);font-family:inherit;background:var(--color-bg-card);color:var(--color-text);transition:border-color var(--transition-fast),box-shadow var(--transition-fast)}input::placeholder,textarea::placeholder{color:var(--color-text-muted)}input:focus,select:focus,textarea:focus{outline:none;border-color:var(--color-primary);box-shadow:var(--shadow-glow)}label{display:block;margin-bottom:var(--space-xs);font-weight:500;font-size:var(--text-xs);color:var(--color-text-light);letter-spacing:.01em}.card,.field{margin-bottom:var(--space-md)}.card{background:var(--gradient-card);border:1px solid var(--color-border-light);border-radius:var(--radius-lg);padding:var(--space-md);box-shadow:var(--shadow-sm);transition:box-shadow var(--transition-base),transform var(--transition-base)}.card:hover{box-shadow:var(--shadow-md)}.brief-box{background:linear-gradient(180deg,#FFF9EC,#FEF7E6);border-left:3px solid var(--color-warn-border);padding:var(--space-md);border-radius:var(--radius-md);white-space:pre-wrap;font-family:ui-monospace,SF Mono,Cascadia Code,Menlo,monospace;margin-top:var(--space-sm);color:var(--color-text);box-shadow:inset 0 1px 0 rgba(255,255,255,.5)}.brief-box,table{font-size:var(--text-xs)}table{width:100%;border-collapse:collapse}td,th{text-align:left;padding:var(--space-sm);border-bottom:1px solid var(--color-border-light)}th{background:var(--color-bg-alt);font-weight:600;color:var(--color-text-light);letter-spacing:.02em;text-transform:uppercase;font-size:11px}::-webkit-scrollbar{width:8px;height:8px}::-webkit-scrollbar-track{background:transparent}::-webkit-scrollbar-thumb{background:var(--color-border);border-radius:var(--radius-full);border:2px solid transparent;background-clip:content-box}::-webkit-scrollbar-thumb:hover{background:var(--color-text-muted);background-clip:content-box}::selection{background:rgba(0,160,235,.18);color:var(--color-primary-darker)}@media (max-width:640px){body{font-size:15px}table,td,th{font-size:12px;padding:6px}}.grid-auto{display:grid;grid-gap:10px;gap:10px;grid-template-columns:repeat(auto-fit,minmax(var(--grid-min,240px),1fr))}.learner-main{max-width:820px;margin:0 auto;padding:0 clamp(16px,4vw,32px)}.section-pad{padding:clamp(20px,4vw,32px) 0}.hero-title{font-size:clamp(26px,6vw,40px);line-height:1.15;letter-spacing:-.03em;font-weight:700}.stat-row{display:flex;flex-wrap:wrap;gap:clamp(16px,3vw,28px);align-items:center;padding:14px clamp(14px,3vw,18px)}@media (max-width:640px){.hide-mobile{display:none!important}}@media (min-width:641px){.hide-desktop{display:none!important}}.cta-btn{white-space:nowrap;font-size:clamp(12px,2.5vw,13px);padding:clamp(8px,2vw,10px) clamp(12px,3vw,18px)}@media (max-width:640px){header nav{gap:10px!important;font-size:12px!important;flex-wrap:wrap!important}header strong{font-size:13px}header>div span{display:none}}