:root{--color-deep-slate: #242834;--color-neon-lime: #B6FF00;--color-bright-purple: #7D53FF;--md-sys-color-primary: var(--color-bright-purple);--md-sys-color-on-primary: #FFFFFF;--md-sys-color-primary-container: rgba(125, 83, 255, .08);--md-sys-color-on-primary-container: var(--color-bright-purple);--md-sys-color-secondary: var(--color-deep-slate);--md-sys-color-on-secondary: #FFFFFF;--md-sys-color-secondary-container: #ECE9F7;--md-sys-color-on-secondary-container: var(--color-bright-purple);--md-sys-color-tertiary: var(--color-neon-lime);--md-sys-color-on-tertiary: #242834;--md-sys-color-tertiary-container: rgba(182, 255, 0, .15);--md-sys-color-on-tertiary-container: #242834;--md-sys-color-error: #EF4444;--md-sys-color-on-error: #FFFFFF;--md-sys-color-error-container: #FEE2E2;--md-sys-color-on-error-container: #EF4444;--md-sys-color-background: #F4F5F7;--md-sys-color-on-background: var(--color-deep-slate);--md-sys-color-surface: #FFFFFF;--md-sys-color-on-surface: var(--color-deep-slate);--md-sys-color-surface-variant: #EBEBEB;--md-sys-color-on-surface-variant: #46464C;--md-sys-color-surface-container-lowest: #FFFFFF;--md-sys-color-surface-container-low: #FAFAFA;--md-sys-color-surface-container: #F4F5F7;--md-sys-color-surface-container-high: #EAEAEA;--md-sys-color-surface-container-highest: #DFDFDF;--md-sys-color-outline: rgba(36, 40, 52, .15);--md-sys-color-outline-variant: rgba(36, 40, 52, .08);--md-sys-typescale-font-family: "Inter", "Noto Sans Khmer", ui-sans-serif, system-ui, sans-serif}.learn-layout{display:flex;height:100vh;max-height:100vh;overflow:hidden;background:var(--md-sys-color-surface-variant);font-family:var(--md-sys-typescale-font-family)}.learn-sidebar{width:320px;background:var(--md-sys-color-surface);border-right:1px solid var(--md-sys-color-outline-variant);display:flex;flex-direction:column;position:fixed;left:0;top:0;bottom:0;height:100vh;overflow-y:auto;overflow-x:hidden;z-index:200;transition:transform .3s cubic-bezier(.4,0,.2,1)}.sidebar-header{padding:16px;height:64px;display:flex;align-items:center;border-bottom:1px solid var(--md-sys-color-outline-variant)}.back-link{display:flex;align-items:center;gap:8px;color:var(--md-sys-color-on-surface);font-weight:500;text-decoration:none;transition:color .2s}.back-link:hover{color:var(--md-sys-color-primary)}.module-header{padding:16px 20px 8px;border-top:1px solid var(--md-sys-color-outline-variant)}.module-header:first-of-type{border-top:none}.module-label{color:var(--md-sys-color-primary);font-size:11px;font-weight:700;text-transform:uppercase;letter-spacing:.75px}.module-title{color:var(--md-sys-color-on-surface);font-size:13px;font-weight:600;margin-top:2px;display:block}.lesson-item{display:flex;align-items:center;gap:10px;padding:8px 16px;margin:2px 12px;border-radius:8px;color:var(--md-sys-color-on-surface-variant);text-decoration:none;transition:all .2s ease;font-size:13.5px}.lesson-item:hover{background:var(--md-sys-color-surface-container);color:var(--md-sys-color-on-surface)}.lesson-item-active{background:var(--md-sys-color-primary-container);color:var(--md-sys-color-primary);font-weight:600}.module-locked{opacity:.6}.module-locked .lock-icon{color:var(--md-sys-color-error);vertical-align:middle}.lesson-item-locked{display:flex;align-items:center;gap:8px;padding:10px 16px;color:var(--md-sys-color-on-surface-variant);opacity:.5;cursor:not-allowed;font-size:14px;pointer-events:none}.lesson-item-locked .lesson-number{background:var(--md-sys-color-outline-variant)}.lesson-item-locked .material-symbols-rounded{color:var(--md-sys-color-outline)}.lesson-number{width:24px;height:24px;border-radius:50%;background:var(--md-sys-color-surface-variant);display:flex;align-items:center;justify-content:center;font-size:12px;font-weight:500}.lesson-item-active .lesson-number{background:var(--md-sys-color-primary);color:var(--md-sys-color-on-primary)}.lesson-icon-video,.lesson-icon-reading,.lesson-icon-quiz,.lesson-icon-assignment{color:var(--md-sys-color-on-surface-variant);transition:color .2s}.lesson-item-active .lesson-icon-video,.lesson-item-active .lesson-icon-reading,.lesson-item-active .lesson-icon-quiz,.lesson-item-active .lesson-icon-assignment{color:var(--md-sys-color-on-primary-container)}.lesson-item:hover .lesson-icon-video,.lesson-item:hover .lesson-icon-reading,.lesson-item:hover .lesson-icon-quiz,.lesson-item:hover .lesson-icon-assignment{color:var(--md-sys-color-primary)}.learn-main{flex:1;margin-left:320px;display:flex;flex-direction:column;min-width:0;padding-bottom:80px;height:100vh;overflow-y:auto;background:var(--md-sys-color-surface)}.video-container{background:var(--md-sys-color-surface);padding:32px;height:calc(100vh - 80px);display:flex;align-items:center;justify-content:center}.video-wrapper{position:relative;width:100%;max-width:800px;aspect-ratio:16 / 9}.video-wrapper iframe{position:absolute;top:0;left:0;width:100%;height:100%;border:none;border-radius:12px}.reading-container{flex:1;padding:32px;background:var(--md-sys-color-surface)}.reading-content{max-width:800px;margin:0 auto;font-size:16px;line-height:1.8;color:var(--md-sys-color-on-surface)}.reading-content h1{font-size:2.25rem;font-weight:800;margin-top:2rem;margin-bottom:1rem;color:var(--md-sys-color-on-surface);line-height:1.3}.reading-content h2{font-size:1.75rem;font-weight:700;margin-top:1.75rem;margin-bottom:.85rem;color:var(--md-sys-color-on-surface);line-height:1.4;border-bottom:1px solid var(--md-sys-color-outline-variant);padding-bottom:.5rem}.reading-content h3{font-size:1.35rem;font-weight:600;margin-top:1.5rem;margin-bottom:.75rem;color:var(--md-sys-color-on-surface)}.reading-content p{margin-top:0;margin-bottom:1.25rem;color:var(--md-sys-color-on-surface-variant)}.reading-content strong{font-weight:700;color:var(--md-sys-color-on-surface)}.reading-content em{font-style:italic}.reading-content ul{list-style-type:disc;padding-left:1.5rem;margin-top:0;margin-bottom:1.25rem}.reading-content ol{list-style-type:decimal;padding-left:1.5rem;margin-top:0;margin-bottom:1.25rem}.reading-content li{margin-bottom:.5rem;color:var(--md-sys-color-on-surface-variant)}.reading-content blockquote{border-left:4px solid var(--md-sys-color-primary);background-color:var(--md-sys-color-surface-container);padding:1rem 1.5rem;margin:1.5rem 0;border-radius:0 8px 8px 0;font-style:italic}.reading-content blockquote p{margin:0;color:var(--md-sys-color-on-surface)}.reading-content code{font-family:var(--font-mono, "JetBrains Mono", monospace);font-size:.9em;background-color:var(--md-sys-color-surface-container-high);color:#e01e5a;padding:.2rem .4rem;border-radius:4px}.reading-content pre{font-family:var(--font-mono, "JetBrains Mono", monospace);background-color:#1a1d27;color:#f8f8f2;padding:1.25rem;border-radius:8px;overflow-x:auto;margin:1.5rem 0;border:1px solid var(--md-sys-color-outline-variant)}.reading-content pre code{background-color:transparent;color:inherit;padding:0;font-size:.9em}.reading-content img{max-width:100%;height:auto;border-radius:12px;margin:1.5rem 0;box-shadow:0 4px 15px #0000000d}.reading-content table{width:100%;border-collapse:collapse;margin:1.5rem 0;font-size:.95rem}.reading-content th,.reading-content td{padding:.75rem 1rem;border-bottom:1px solid var(--md-sys-color-outline-variant);text-align:left}.reading-content th{font-weight:600;background-color:var(--md-sys-color-surface-variant);color:var(--md-sys-color-on-surface)}.reading-content hr{border:0;border-top:1px solid var(--md-sys-color-outline-variant);margin:2rem 0}.quiz-container{padding:32px;max-width:900px;width:100%;margin:0 auto;color:var(--md-sys-color-on-surface);display:flex;flex-direction:column;min-height:calc(100vh - 80px);justify-content:center}.quiz-header{width:100%;margin-bottom:20px}.question-card{width:100%;background:transparent;padding:0;box-shadow:none;border:none;margin-bottom:32px}.question-text{font-size:28px;font-weight:700;line-height:1.3;margin-bottom:12px;color:var(--md-sys-color-on-surface)}.question-subtext{font-size:16px;color:var(--md-sys-color-on-surface-variant)}.option-btn{display:flex;align-items:center;gap:16px;padding:18px 24px;border:1px solid transparent;border-radius:9999px;background:transparent;cursor:pointer;text-align:left;transition:all .2s cubic-bezier(.4,0,.2,1);width:100%;color:var(--md-sys-color-on-surface);margin-bottom:16px;font-size:16px;position:relative;box-shadow:none}.option-btn:hover:not(.answered){background:var(--md-sys-color-primary-container);color:var(--md-sys-color-on-primary-container);border-color:transparent;box-shadow:none}.option-btn:hover:not(.answered) .option-radio{border-color:var(--md-sys-color-primary)}.option-radio{width:24px;height:24px;border-radius:50%;border:2px solid var(--md-sys-color-outline);display:flex;align-items:center;justify-content:center;transition:all .2s;flex-shrink:0;background:transparent}.option-radio.selected{border-color:var(--md-sys-color-primary);background:transparent}.option-radio.selected:after{content:"";width:12px;height:12px;border-radius:50%;background:var(--md-sys-color-primary)}.option-btn.correct{border-color:var(--md-sys-color-primary);background:color-mix(in srgb,var(--md-sys-color-primary),transparent 90%)}.option-btn.correct .option-radio{border-color:var(--md-sys-color-primary);background:var(--md-sys-color-primary)}.option-btn.incorrect{border-color:var(--md-sys-color-error);background:color-mix(in srgb,var(--md-sys-color-error),transparent 90%)}.option-btn.incorrect .option-radio{border-color:var(--md-sys-color-error)}.feedback-correct{background:var(--md-sys-color-primary-container);color:var(--md-sys-color-on-primary-container);padding:16px;border-radius:12px;margin-top:16px;font-weight:500}.feedback-incorrect{background:var(--md-sys-color-error-container);color:var(--md-sys-color-on-error-container);padding:16px;border-radius:12px;margin-top:16px;font-weight:500}.assignment-container{padding:32px;max-width:800px;margin:0 auto;color:var(--md-sys-color-on-surface)}.assignment-card{background:var(--md-sys-color-surface);border-radius:16px;padding:24px;margin-bottom:24px;box-shadow:0 4px 12px #0000000f}.submission-input{width:100%;padding:16px;border:1px solid var(--md-sys-color-outline);border-radius:12px;font-size:14px;margin-bottom:16px;background:var(--md-sys-color-surface);color:var(--md-sys-color-on-surface)}.submission-input:focus{outline:none;border-color:var(--md-sys-color-primary);box-shadow:0 0 0 2px var(--md-sys-color-primary-container)}.lesson-navigation{display:flex;justify-content:space-between;padding:16px 24px;background:var(--md-sys-color-surface-container-low);border:1px solid var(--md-sys-color-outline-variant);border-radius:16px;margin:40px auto;width:calc(100% - 64px);max-width:800px;box-shadow:0 4px 12px #00000005;box-sizing:border-box;transition:all .3s ease}.nav-btn{display:flex;align-items:center;gap:8px;padding:10px 20px;border-radius:10px;background:var(--md-sys-color-surface-container-high);color:var(--md-sys-color-on-surface);font-weight:600;text-decoration:none;transition:all .2s ease;border:1px solid var(--md-sys-color-outline-variant);cursor:pointer}.nav-btn:hover:not(.disabled){background:var(--md-sys-color-primary-container);color:var(--md-sys-color-primary);border-color:var(--md-sys-color-primary)}.nav-btn-primary{background:var(--md-sys-color-primary);color:var(--md-sys-color-on-primary);border:1px solid var(--md-sys-color-primary)}.nav-btn-primary:hover:not(.disabled){filter:brightness(1.08);box-shadow:0 4px 12px #7d53ff33}.nav-btn.disabled{opacity:.35;pointer-events:none}.mobile-header{display:none;align-items:center;justify-content:space-between;height:56px;padding:0 16px;background:var(--md-sys-color-surface);border-bottom:1px solid var(--md-sys-color-outline-variant);position:sticky;top:0;left:0;right:0;z-index:150;box-sizing:border-box}.mobile-header .menu-btn{background:transparent;border:none;color:var(--md-sys-color-on-surface);cursor:pointer;display:flex;align-items:center;justify-content:center;width:40px;height:40px;border-radius:50%;transition:background .2s}.mobile-header .menu-btn:hover{background:var(--md-sys-color-surface-container)}.mobile-course-title{font-size:16px;font-weight:600;color:var(--md-sys-color-on-surface);text-align:center;flex:1;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;padding:0 12px}.mobile-header .mobile-back-btn{color:var(--md-sys-color-on-surface);text-decoration:none;display:flex;align-items:center;justify-content:center;width:40px;height:40px;border-radius:50%;transition:background .2s}.mobile-header .mobile-back-btn:hover{background:var(--md-sys-color-surface-container)}.sidebar-backdrop{position:fixed;inset:0;background:#24283466;z-index:199;opacity:0;visibility:hidden;transition:all .3s ease;pointer-events:none}.sidebar-backdrop.visible{opacity:1;visibility:visible;pointer-events:auto}@media(max-width:768px){.learn-sidebar{transform:translate(-100%);box-shadow:0 0 24px #00000026}.learn-sidebar.open{transform:translate(0)}.mobile-close-btn{display:flex!important}.mobile-header{display:flex}.learn-main{margin-left:0;height:calc(100vh - 56px)}.lesson-navigation{margin:24px 16px;width:calc(100% - 32px)}.scroll-progress-container{left:0;top:56px}}.theme-switch-wrapper{display:flex;align-items:center}.theme-switch{display:inline-block;height:28px;position:relative;width:52px}.theme-switch input{display:none}.slider{background-color:var(--md-sys-color-surface-variant);cursor:pointer;inset:0;position:absolute;transition:.4s;border:1px solid var(--md-sys-color-outline-variant)}.slider:before{background-color:var(--md-sys-color-primary);bottom:3px;content:"";height:20px;left:4px;position:absolute;transition:.4s;width:20px}.slider.round{border-radius:34px}.slider.round:before{border-radius:50%}input:checked+.slider{background-color:var(--md-sys-color-secondary-container);border-color:var(--md-sys-color-primary)}input:checked+.slider:before{transform:translate(22px);background-color:var(--md-sys-color-on-secondary-container)}.switch-icon{position:absolute;top:50%;transform:translateY(-50%);font-size:16px;color:var(--md-sys-color-on-surface-variant);z-index:1;pointer-events:none;transition:opacity .3s}.icon-light{left:6px;opacity:1}.icon-dark{right:6px;opacity:1}input:checked~.icon-light{opacity:.5}input:not(:checked)~.icon-dark{opacity:.5}.constructing-overlay{position:fixed;inset:0;background:var(--md-sys-color-background);display:flex;align-items:center;justify-content:center;z-index:1000;animation:overlayFadeIn .3s ease-out}@keyframes overlayFadeIn{0%{opacity:0}to{opacity:1}}.constructing-content{display:flex;flex-direction:column;align-items:center;gap:24px;padding:32px;max-width:500px;width:100%}.construct-title{display:flex;align-items:center;gap:16px;opacity:0;transform:translateY(20px);transition:all .5s cubic-bezier(.4,0,.2,1)}.construct-title.visible{opacity:1;transform:translateY(0)}.construct-title h1{font-size:24px;font-weight:600;color:var(--md-sys-color-on-surface);margin:0}.construct-icon{font-size:40px;color:var(--md-sys-color-primary);animation:iconPulse 1.5s ease-in-out infinite}@keyframes iconPulse{0%,to{transform:scale(1)}50%{transform:scale(1.1)}}.construct-message{font-size:16px;color:var(--md-sys-color-on-surface-variant);opacity:0;transform:translateY(10px);transition:all .4s ease-out}.construct-message.visible{opacity:1;transform:translateY(0)}.construct-preview{position:relative;width:100%;max-width:400px;height:200px;background:var(--md-sys-color-surface-variant);border-radius:16px;overflow:hidden;opacity:0;transform:scale(.9);transition:all .5s cubic-bezier(.4,0,.2,1);display:flex}.construct-preview.visible{opacity:1;transform:scale(1)}.preview-sidebar{width:100px;background:var(--md-sys-color-surface);border-right:1px solid var(--md-sys-color-outline-variant);padding:12px;display:flex;flex-direction:column;gap:8px;transform:translate(-100%);transition:transform .4s cubic-bezier(.4,0,.2,1)}.preview-sidebar.slide-in{transform:translate(0)}.preview-header-block{height:12px;background:var(--md-sys-color-primary);border-radius:4px;opacity:.6}.preview-item-block{height:8px;background:var(--md-sys-color-outline-variant);border-radius:4px}.preview-item-block.short{width:60%}.preview-main{flex:1;display:flex;align-items:center;justify-content:center;opacity:0;transform:translateY(20px);transition:all .5s cubic-bezier(.4,0,.2,1)}.preview-main.build-up{opacity:1;transform:translateY(0)}.preview-video-block{width:120px;height:70px;background:var(--md-sys-color-surface);border-radius:8px;display:flex;align-items:center;justify-content:center;box-shadow:0 4px 12px #0000001a}.preview-video-block .material-symbols-rounded{font-size:32px;color:var(--md-sys-color-primary);animation:playBounce 1s ease-in-out infinite}@keyframes playBounce{0%,to{transform:scale(1)}50%{transform:scale(1.15)}}.preview-nav{position:absolute;bottom:0;left:100px;right:0;height:40px;background:var(--md-sys-color-surface);border-top:1px solid var(--md-sys-color-outline-variant);display:flex;align-items:center;justify-content:space-between;padding:0 16px;transform:translateY(100%);transition:transform .4s cubic-bezier(.4,0,.2,1)}.preview-nav.slide-up{transform:translateY(0)}.preview-nav-btn{width:60px;height:20px;background:var(--md-sys-color-surface-variant);border-radius:10px}.preview-nav-btn.primary{background:var(--md-sys-color-primary);opacity:.7}.construct-progress{width:100%;max-width:300px;height:6px;background:var(--md-sys-color-surface-variant);border-radius:3px;overflow:hidden}.construct-progress-bar{height:100%;background:linear-gradient(90deg,var(--md-sys-color-primary),var(--md-sys-color-tertiary));border-radius:3px;transition:width .1s linear;box-shadow:0 0 10px var(--md-sys-color-primary)}.construct-icons{display:flex;gap:24px;opacity:0;transition:opacity .3s ease-out}.construct-icons.visible{opacity:1}.construct-icons .material-symbols-rounded{font-size:28px;color:var(--md-sys-color-on-surface-variant);opacity:0;transform:scale(0)}.construct-icons .material-symbols-rounded.pop-in{animation:popIn .4s cubic-bezier(.68,-.55,.265,1.55) forwards}@keyframes popIn{0%{opacity:0;transform:scale(0) rotate(-20deg)}to{opacity:1;transform:scale(1) rotate(0)}}.learn-layout.entering .learn-sidebar{animation:sidebarSlideIn .5s cubic-bezier(.4,0,.2,1) forwards}.learn-layout.entering .learn-main{animation:mainFadeIn .6s cubic-bezier(.4,0,.2,1) .2s forwards;opacity:0}.learn-layout.entering .lesson-navigation{animation:navSlideUp .4s cubic-bezier(.4,0,.2,1) .4s forwards;opacity:0;transform:translateY(100%)}@keyframes sidebarSlideIn{0%{transform:translate(-100%);opacity:0}to{transform:translate(0);opacity:1}}@keyframes mainFadeIn{0%{opacity:0;transform:scale(.98)}to{opacity:1;transform:scale(1)}}@keyframes navSlideUp{0%{opacity:0;transform:translateY(100%)}to{opacity:1;transform:translateY(0)}}.scroll-progress-container{position:fixed;top:0;left:320px;right:0;height:4px;background-color:transparent;z-index:1000;pointer-events:none}.scroll-progress-bar{height:100%;background-color:var(--color-neon-lime);box-shadow:0 0 8px var(--color-neon-lime);transition:width .08s ease-out}@media(max-width:768px){.scroll-progress-container{left:0}}