:root{--color-primary:#409eff;--color-primary-light:#66b1ff;--color-primary-dark:#3a8ee6;--color-primary-bg:#ecf5ff;--color-success:#67c23a;--color-success-light:#85ce61;--color-success-bg:#f0f9eb;--color-warning:#e6a23c;--color-warning-light:#ebb563;--color-warning-bg:#fdf6ec;--color-danger:#f56c6c;--color-danger-light:#f78989;--color-danger-bg:#fef0f0;--color-info:#909399;--color-bg:#f5f7fa;--color-bg-white:#fff;--color-bg-hover:#f5f7ff;--color-text:#303133;--color-text-secondary:#606266;--color-text-placeholder:#c0c4cc;--color-border:#dcdfe6;--color-border-light:#e4e7ed;--color-border-dark:#c0c4cc;--color-divider:#ebeef5;--color-correct:var(--color-success);--color-correct-bg:var(--color-success-bg);--color-wrong:var(--color-danger);--color-wrong-bg:var(--color-danger-bg);--color-review:var(--color-warning);--color-review-bg:var(--color-warning-bg);--color-hover-highlight:var(--color-primary-bg);--color-grammar-highlight:#fde68a;--proficiency-low:#f56c6c;--proficiency-mid:#e6a23c;--proficiency-high:#67c23a;--btn-known-bg:#e1f3d8;--btn-known-border:#b3e19d;--btn-known-text:#529b2e;--btn-known-hover-bg:#c6e8b5;--btn-unknown-bg:#fde2e2;--btn-unknown-border:#f3b6b6;--btn-unknown-text:#c45656;--btn-unknown-hover-bg:#fbd0d0;--whiteboard-red:#e74c3c;--whiteboard-blue:#3498db;--whiteboard-black:#2c3e50;--font-family-base:-apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", sans-serif;--font-xs:11px;--font-sm:12px;--font-base:14px;--font-md:16px;--font-lg:18px;--font-xl:20px;--font-2xl:24px;--font-3xl:28px;--font-4xl:32px;--font-5xl:36px;--font-display:48px;--font-normal:400;--font-medium:500;--font-semibold:600;--font-bold:700;--leading-tight:1.25;--leading-normal:1.5;--leading-relaxed:1.6;--space-1:4px;--space-2:8px;--space-3:12px;--space-4:16px;--space-5:20px;--space-6:24px;--space-8:32px;--radius-sm:4px;--radius-md:8px;--radius-lg:12px;--radius-full:9999px;--shadow-sm:0 1px 3px #0000001a;--shadow-md:0 4px 12px #0000001a;--shadow-lg:0 8px 24px #0000001f;--duration-fast:.15s;--duration-normal:.2s;--duration-slow:.3s;--duration-page:.35s;--duration-loading:1.2s;--ease-out:ease-out;--ease-in-out:ease-in-out;--ease-spring:cubic-bezier(.34, 1.56, .64, 1);--transition-fade:opacity var(--duration-normal) var(--ease-out);--transition-slide-up:opacity var(--duration-slow) var(--ease-out), transform var(--duration-slow) var(--ease-out);--transition-color:background var(--duration-normal) var(--ease-out), border-color var(--duration-normal) var(--ease-out);--transition-all:all var(--duration-normal) var(--ease-out)}@keyframes dt-meta-dot-pulse{0%,80%,to{opacity:.3;transform:scale(.8)}40%{opacity:1;transform:scale(1)}}@keyframes dt-shake{0%,to{transform:translate(0)}25%{transform:translate(-4px)}75%{transform:translate(4px)}}@keyframes dt-fade-in-up{0%{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}@keyframes dt-fade-in{0%{opacity:0}to{opacity:1}}@keyframes dt-cursor-blink{0%,50%{opacity:1}51%,to{opacity:0}}.dt-fade-in-up{animation:dt-fade-in-up var(--duration-slow) var(--ease-out) both}.dt-fade-in{animation:dt-fade-in var(--duration-normal) var(--ease-out) both}.dt-slide-enter-from{opacity:0;transform:translateY(8px)}.dt-slide-enter-active{transition:var(--transition-slide-up)}.dt-slide-leave-active{transition:var(--transition-fade)}.dt-slide-leave-to,.dt-fade-enter-from,.dt-fade-leave-to{opacity:0}.dt-fade-enter-active,.dt-fade-leave-active{transition:var(--transition-fade)}.dt-cursor:after{content:"|";color:var(--color-primary);margin-left:1px;animation:.8s infinite dt-cursor-blink;display:inline-block}.dt-loading-dots{align-items:center;gap:4px;display:inline-flex}.dt-loading-dot{border-radius:var(--radius-full);background:var(--color-text-placeholder);width:6px;height:6px;animation:dt-meta-dot-pulse var(--duration-loading) var(--ease-in-out) infinite}.dt-card{background:var(--color-bg-white);border-radius:var(--radius-md);box-shadow:var(--shadow-sm)}.dt-review-pattern{background:repeating-linear-gradient(135deg,#fafbfc 0 12px,#f0f4f8 12px 24px)}.dt-grammar-highlight{background:linear-gradient(180deg, transparent 55%, var(--color-grammar-highlight) 55%)}:root{--el-color-primary:var(--color-primary);--el-color-primary-light-3:var(--color-primary-light);--el-color-primary-light-5:#a0cfff;--el-color-primary-light-7:#c6e2ff;--el-color-primary-light-8:#d9ecff;--el-color-primary-light-9:var(--color-primary-bg);--el-color-primary-dark-2:var(--color-primary-dark);--el-color-success:var(--color-success);--el-color-success-light-3:var(--color-success-light);--el-color-success-light-5:#b3e19d;--el-color-success-light-7:#d2edc4;--el-color-success-light-9:var(--color-success-bg);--el-color-warning:var(--color-warning);--el-color-warning-light-3:var(--color-warning-light);--el-color-warning-light-5:#f3d19e;--el-color-warning-light-7:#f8e3c5;--el-color-warning-light-9:var(--color-warning-bg);--el-color-danger:var(--color-danger);--el-color-danger-light-3:var(--color-danger-light);--el-color-danger-light-5:#fab6b6;--el-color-danger-light-7:#fcd3d3;--el-color-danger-light-9:var(--color-danger-bg);--el-color-info:var(--color-info);--el-text-color-primary:var(--color-text);--el-text-color-regular:var(--color-text-secondary);--el-text-color-secondary:var(--color-text-secondary);--el-text-color-placeholder:var(--color-text-placeholder);--el-bg-color:var(--color-bg-white);--el-bg-color-page:var(--color-bg);--el-border-color:var(--color-border);--el-border-color-light:var(--color-border-light);--el-border-color-lighter:var(--color-divider);--el-border-color-extra-light:var(--color-divider);--el-border-radius-base:var(--radius-md);--el-border-radius-small:var(--radius-sm);--el-border-radius-round:var(--radius-full);--el-font-size-extra-small:var(--font-sm);--el-font-size-small:var(--font-base);--el-font-size-base:var(--font-md);--el-font-size-medium:var(--font-lg);--el-font-size-large:var(--font-xl);--el-font-family:var(--font-family-base);--glass-bg:#ffffff14;--glass-bg-strong:#ffffff26;--glass-border:#ffffff1f;--glass-border-strong:#fff3;--glass-blur:20px;--glass-blur-strong:40px;--promo-bg:#0a0e1a;--promo-bg-card:#ffffff08;--promo-text:#e8ecf4;--promo-text-muted:#8892a4;--promo-accent-gradient:linear-gradient(135deg, #409eff, #7c3aed);--promo-glow-blue:#409eff26;--promo-glow-purple:#7c3aed1a;--section-padding:clamp(60px, 10vh, 120px) 0}*,:before,:after{box-sizing:border-box;margin:0;padding:0}html{scroll-behavior:smooth;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}body{font-family:var(--font-family-base);background:var(--promo-bg);color:var(--promo-text);line-height:var(--leading-normal);min-height:100vh;overflow-x:hidden}a{color:var(--color-primary);text-decoration:none}img{max-width:100%;height:auto}::-webkit-scrollbar{width:6px}::-webkit-scrollbar-track{background:0 0}::-webkit-scrollbar-thumb{border-radius:var(--radius-full);background:#ffffff1f}::-webkit-scrollbar-thumb:hover{background:#ffffff40}.glass{background:var(--glass-bg);-webkit-backdrop-filter:blur(var(--glass-blur));border:1px solid var(--glass-border);border-radius:var(--radius-lg)}.glass-strong{background:var(--glass-bg-strong);-webkit-backdrop-filter:blur(var(--glass-blur-strong));border:1px solid var(--glass-border-strong);border-radius:var(--radius-lg)}.text-gradient{background:var(--promo-accent-gradient);-webkit-text-fill-color:transparent;-webkit-background-clip:text;background-clip:text}.section{padding:var(--section-padding);position:relative}.section-container{max-width:1200px;padding:0 var(--space-6);margin:0 auto}.section-title{font-size:var(--font-5xl);font-weight:var(--font-bold);text-align:center;margin-bottom:var(--space-4);letter-spacing:-.02em}.section-subtitle{font-size:var(--font-lg);color:var(--promo-text-muted);text-align:center;max-width:600px;margin:0 auto var(--space-8)}.reveal{opacity:0;transition:opacity .8s var(--ease-out), transform .8s var(--ease-out);transform:translateY(30px)}.reveal.is-visible{opacity:1;transform:translateY(0)}@keyframes glow-pulse{0%,to{box-shadow:0 0 20px #409eff4d,0 0 60px #409eff1a}50%{box-shadow:0 0 40px #409eff80,0 0 100px #7c3aed33}}.glow-pulse{animation:2.5s ease-in-out infinite glow-pulse}@keyframes bounce-down{0%,to{opacity:.6;transform:translateY(0)}50%{opacity:1;transform:translateY(8px)}}.scroll-indicator{cursor:pointer;animation:2s ease-in-out infinite bounce-down}@media (width<=640px){.section-title{font-size:var(--font-3xl)}.section-subtitle{font-size:var(--font-base)}.hide-mobile{display:none!important}}@media (width>=641px){.hide-desktop{display:none!important}}@supports not ((-webkit-backdrop-filter:blur(1px)) or (backdrop-filter:blur(1px))){.glass,.glass-strong{background:#0f121ee6}}