.chat-icon-button{cursor:pointer;background:0 0;border:none;border-radius:8px;justify-content:center;align-items:center;padding:0;transition:all .2s;display:flex;position:relative}.chat-icon-button--large{width:32px;height:32px}.chat-icon-button--large .icon{width:20px;height:20px}.chat-icon-button--small{width:24px;height:24px}.chat-icon-button--small .icon{width:14px;height:14px}.chat-icon-button--default{color:#767676}.chat-icon-button--error{color:#e04949}.chat-icon-button:hover:not(.chat-icon-button--disabled){color:#333;background-color:#f2f2f2}.chat-icon-button:active:not(.chat-icon-button--disabled){background-color:#f2f2f2;box-shadow:inset 0 3px rgba(224,224,224,.7)}.chat-icon-button:focus-visible{outline:2px solid var(--ui-color-brand-fod-primary-a);outline-offset:2px}.chat-icon-button--disabled{opacity:.5;cursor:not-allowed}.chat-mermaid-modal-container{border-radius:var(--border-radius-01);justify-content:center;align-items:center;width:100%;min-height:300px;padding:20px;display:flex}.chat-mermaid-modal-container .chat-mermaid-modal__diagram{text-align:center}.chat-mermaid-modal-container .chat-mermaid-modal__diagram svg{max-width:100%;height:auto}.conversation-history{--conversation-history-row-padding:var(--ui-space-xs)var(--ui-space-md);--conversation-history-title-font-size:var(--ui-font-size-16);--conversation-history-title-line-height:var(--ui-line-height-24);--conversation-history-date-font-size:var(--ui-font-size-14);--conversation-history-date-line-height:var(--ui-line-height-20);overflow:hidden}.conversation-history .chat-dropdown__content{padding:0}.conversation-history__list{margin:0;padding:0;list-style:none}.conversation-history__item{position:relative}.conversation-history__item:not(:last-child):after{content:"";height:var(--ui-stroke-1);background-color:var(--ui-color-neutral-grey-200);position:absolute;bottom:0;left:0;right:0}.conversation-history__item-wrapper{align-items:center;gap:var(--ui-space-xs);padding:var(--conversation-history-row-padding);transition:background-color .2s;display:flex}.conversation-history__item-wrapper:hover{background-color:var(--ui-color-neutral-grey-100)}.conversation-history__button{cursor:pointer;text-align:left;background:0 0;border:none;flex:1;align-items:center;min-width:0;padding:0;display:flex}.conversation-history__info{flex:1;min-width:0}.conversation-history__item-title{font-size:var(--conversation-history-title-font-size);font-weight:var(--ui-font-weight-medium);line-height:var(--conversation-history-title-line-height);color:var(--ui-color-neutral-grey-900);margin-bottom:var(--ui-space-xxxs);white-space:nowrap;text-overflow:ellipsis;font-family:var(--ui-font-family-body);letter-spacing:normal;overflow:hidden}.conversation-history__metadata{font-size:var(--conversation-history-date-font-size);font-weight:var(--ui-font-weight-medium);line-height:var(--conversation-history-date-line-height);color:var(--ui-color-neutral-grey-700);font-family:var(--ui-font-family-body);letter-spacing:normal}.conversation-history__empty{text-align:center;color:#767676;padding:40px 16px;font-size:14px}.conversation-history__loading{text-align:center;color:#767676;flex-direction:column;align-items:center;gap:12px;padding:40px 16px;font-size:14px;display:flex}.conversation-history__spinner{border:2px solid #f2f2f2;border-top-color:var(--ui-color-brand-fod-primary-a);border-radius:50%;width:24px;height:24px;animation:.8s linear infinite spin}.conversation-history__error{text-align:center;color:#f66868;flex-direction:column;align-items:center;gap:8px;padding:40px 16px;font-size:14px;display:flex}.conversation-history__error .icon__wrapper{width:24px;height:24px}.conversation-history__delete-button{cursor:pointer;opacity:1;background:0 0;border:none;border-radius:8px;flex-shrink:0;justify-content:center;align-items:center;width:24px;height:24px;padding:2px;transition:background-color .2s;display:flex}.conversation-history__delete-button:hover{color:#f66868;background-color:rgba(246,104,104,.1)}.conversation-history__delete-button .icon__wrapper{width:20px;height:20px}.conversation-history__new-chat-button{width:100%}.conversation-history__end{text-align:center;color:#767676;font-size:14px;font-family:var(--font-second);padding:16px;font-weight:500}@keyframes spin{0%{transform:rotate(0)}to{transform:rotate(360deg)}}.chat-badge{border-radius:16px;align-items:center;gap:4px;padding:4px 8px;font-size:14px;display:inline-flex}.chat-badge__emoji{font-size:inherit}.chat-badge__text{font-family:var(--font-second);color:transparent;-webkit-background-clip:text;background-clip:text;font-weight:600;line-height:26px}.chat-badge--practice{background-color:#d6f6ff}.chat-badge--practice .chat-badge__text{color:#0a3366}.chat-badge--study{background-color:#ffe8ff}.chat-badge--study .chat-badge__text{color:#6b0a6b}.chat-badge--revision{background-color:#fff3e0}.chat-badge--revision .chat-badge__text{color:#e65100}.teacher-layout-wrapper{height:100vh;display:flex;overflow:hidden}.teacher-layout-wrapper__sidebar{background:var(--color-background);flex-direction:column;flex-shrink:0;width:13rem;height:100vh;transition:width .3s;display:flex;overflow-x:hidden;overflow-y:auto}.teacher-layout-wrapper__sidebar-header{padding:2.25rem var(--ui-space-md)0;justify-content:space-between;align-items:center;display:flex}.teacher-layout-wrapper__collapse-btn{padding:var(--ui-space-xs);cursor:pointer;border-radius:var(--ui-radius-xl);background:0 0;border:none;justify-content:center;align-items:center;transition:background-color .2s;display:flex}.teacher-layout-wrapper__collapse-btn:hover{background-color:var(--ui-color-brand-fod-lighter)}.teacher-layout-wrapper__collapse-btn .icon{color:var(--ui-color-neutral-grey-700)}.teacher-layout-wrapper__title-container{visibility:visible;transition:opacity .3s;overflow:hidden}.teacher-layout-wrapper__title{padding:var(--ui-space-lg)var(--ui-space-md)0;font-family:var(--ui-font-family-heading);font-size:var(--ui-font-size-22);font-weight:var(--ui-font-weight-semibold);line-height:var(--ui-line-height-28);color:var(--ui-color-neutral-grey-700);white-space:nowrap;margin:0}.teacher-layout-wrapper__navigation{padding:var(--ui-space-lg)0 0 var(--ui-space-md);flex:1;transition:padding .3s}.teacher-layout-wrapper__nav-list{gap:var(--ui-space-xs);flex-direction:column;margin:0;padding:0;list-style:none;display:flex}.teacher-layout-wrapper__nav-item{padding:var(--ui-space-xs);border-radius:var(--ui-radius-xl)0 0 var(--ui-radius-xl);cursor:pointer;text-align:left;background:0 0;border:none;align-items:center;width:100%;transition:background-color .2s,color .2s;display:flex;overflow:hidden}.teacher-layout-wrapper__nav-item .icon{width:var(--ui-icon-size-md);height:var(--ui-icon-size-md);color:var(--ui-color-neutral-grey-700);flex-shrink:0;transition:color .2s}.teacher-layout-wrapper__nav-item:hover{background:var(--ui-color-brand-fod-lighter)}.teacher-layout-wrapper__nav-item--active{background:var(--ui-color-neutral-white)}.teacher-layout-wrapper__nav-item--active .icon,.teacher-layout-wrapper__nav-item--active .teacher-layout-wrapper__nav-text{color:var(--ui-color-brand-fod-primary-a)}.teacher-layout-wrapper__nav-item--active:hover{background:var(--ui-color-neutral-white)}.teacher-layout-wrapper__nav-skeleton-item{align-items:center;gap:12px;padding:8px 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.switch__label{font-size:var(--ui-font-size-14)}.teacher-layout-wrapper__dev-toggle-hint{color:var(--ui-color-neutral-grey-500);margin-top:4px;font-size:11px;line-height:1.3}.teacher-layout-wrapper__main{background:var(--ui-color-neutral-white);flex:1;min-width:0;padding-top:36px;padding-bottom:36px;overflow:auto}.teacher-layout-wrapper__main--default-padding{padding-left:72px;padding-right:72px}.teacher-layout-wrapper__main--left-only-padding{padding-left:72px;padding-right:0}.teacher-layout-wrapper__main--none-padding{padding-left:0;padding-right:0}.teacher-layout-wrapper--collapsed .teacher-layout-wrapper__sidebar{width:5rem}.teacher-layout-wrapper--collapsed .teacher-layout-wrapper__sidebar-header{justify-content:center;padding-left:0;padding-right:0}.teacher-layout-wrapper--collapsed .teacher-layout-wrapper__sidebar-header .back-arrow{display:none}.teacher-layout-wrapper--collapsed .teacher-layout-wrapper__title-container{opacity:0;visibility:hidden;transition:opacity .3s,visibility 0s linear .3s}.teacher-layout-wrapper--collapsed .teacher-layout-wrapper__navigation{padding:var(--ui-space-lg)0 0 var(--ui-space-md);align-items:center}.teacher-layout-wrapper--collapsed .teacher-layout-wrapper__nav-item{padding:var(--ui-space-xs);justify-content:center}.teacher-layout-wrapper--collapsed .teacher-layout-wrapper__sidebar-footer{--teacher-layout-footer-padding-inline:var(--ui-space-xs);align-items:center}.teacher-layout-wrapper--collapsed .teacher-layout-wrapper__nav-text{opacity:0;width:0;margin-left:0;transition:opacity .2s ease-out,width .3s,margin-left .3s}.teacher-layout-wrapper--show-back-collapsed .teacher-layout-wrapper__sidebar-header .back-arrow{display:flex}.teacher-layout-wrapper__mobile-menu-button,.teacher-layout-wrapper__mobile-menu-backdrop{display:none}.quadrant-chart{--quadrant-chart-gutter:40px;padding:var(--quadrant-chart-gutter);min-height:600px;position:relative}.quadrant-chart--loading{justify-content:center;align-items:center;display:flex}.quadrant-chart__corner-label{font-family:var(--font-second);color:#333;white-space:nowrap;z-index:2;border-radius:16px;padding:4px 8px;font-size:14px;font-weight:500;line-height:20px;position:absolute}.quadrant-chart__corner-label--top-left{top:calc(var(--quadrant-chart-gutter)/2);background-color:#ffebe2;left:0;transform:translateY(-50%)}.quadrant-chart__corner-label--top-right{top:calc(var(--quadrant-chart-gutter)/2);background-color:#d7fedb;right:0;transform:translateY(-50%)}.quadrant-chart__corner-label--bottom-left{bottom:calc(var(--quadrant-chart-gutter)/2);background-color:#ffeaed;left:0;transform:translateY(50%)}.quadrant-chart__corner-label--bottom-right{bottom:calc(var(--quadrant-chart-gutter)/2);background-color:#d6f6ff;right:0;transform:translateY(50%)}.quadrant-chart__axis-horizontal{top:50%;left:var(--quadrant-chart-gutter);right:var(--quadrant-chart-gutter);z-index:1;background-color:#767676;height:1px;position:absolute}.quadrant-chart__axis-vertical{left:50%;top:var(--quadrant-chart-gutter);bottom:var(--quadrant-chart-gutter);z-index:1;background-color:#767676;width:1px;position:absolute}.quadrant-chart__axis-label{font-family:var(--font-second);color:#4e4e4e;text-transform:uppercase;letter-spacing:.5px;white-space:nowrap;z-index:2;background-color:#f9f9f9;align-items:center;gap:4px;padding:8px 0;font-size:12px;font-weight:700;line-height:18px;display:flex;position:absolute}.quadrant-chart__axis-label .icon__wrapper{flex-shrink:0}.quadrant-chart__axis-label--x-negative{top:50%;left:calc(var(--quadrant-chart-gutter)/2);transform:translate(-50%,-50%)rotate(-90deg)}.quadrant-chart__axis-label--x-positive{top:50%;right:calc(var(--quadrant-chart-gutter)/2);transform:translate(50%,-50%)rotate(-90deg)}.quadrant-chart__axis-label--y-positive{left:50%;top:calc(var(--quadrant-chart-gutter)/2);transform:translate(-50%,-50%)}.quadrant-chart__axis-label--y-negative{left:50%;bottom:calc(var(--quadrant-chart-gutter)/2);transform:translate(-50%,50%)}.quadrant-chart__area{height:calc(600px - var(--quadrant-chart-gutter)*2);z-index:3;width:100%;position:relative}.quadrant-chart__cluster{-webkit-appearance:none;appearance:none;cursor:pointer;background:0 0;border:none;border-radius:60px;justify-content:center;align-items:center;padding:0;display:flex;position:absolute}.quadrant-chart__cluster--single .avatar{width:48px;height:48px}.quadrant-chart__cluster--multi{background-color:#333;border:2px solid #fff}.quadrant-chart__cluster-count{font-family:var(--font-second);color:#fff;font-size:16px;font-weight:700;line-height:24px}.topic-ranking-section{background-color:#fff;flex-direction:column;gap:16px;padding:16px 24px;display:flex;overflow:hidden}.topic-ranking-section__header{justify-content:space-between;align-items:flex-start;display:flex}.topic-ranking-section__header-titles{flex-direction:column;gap:8px;display:flex}.topic-ranking-section__title{font-family:var(--font-first);color:#333;margin:0;font-size:22px;font-weight:600;line-height:32px}.topic-ranking-section__subtitle{font-family:var(--font-second);color:#4e4e4e;margin:0;font-size:16px;font-weight:400;line-height:24px}.topic-ranking-section__header-actions{flex-shrink:0;align-items:center;display:flex}.topic-ranking-section__view-toggle{background-color:#f2f2f2;border-radius:4px;align-items:center;gap:4px;padding:8px;display:flex}.topic-ranking-section__view-toggle-btn{cursor:pointer;color:#ababab;background:0 0;border:none;border-radius:4px;justify-content:center;align-items:center;padding:2px;transition:color .2s,background-color .2s;display:flex}.topic-ranking-section__view-toggle-btn .icon--color-default{color:#4e4e4e}.topic-ranking-section__view-toggle-btn--active{color:#333;background-color:#fff}.topic-ranking-section__view-toggle-btn--active .icon--color-default{color:var(--ui-color-brand-fod-primary-a)}.topic-ranking-section__view-toggle-btn--active:hover:not(:disabled) .icon--color-default{color:var(--ui-color-brand-fod-dark)}.topic-ranking-section__view-toggle-btn:disabled{opacity:.5;cursor:not-allowed}.topic-ranking-section__filters-row{justify-content:space-between;align-items:flex-start;gap:24px;display:flex}.topic-ranking-section__description{font-family:var(--font-second);color:#4e4e4e;flex:1;min-width:0;margin:0;font-size:16px;font-weight:400;line-height:20px}.topic-ranking-section__filters{flex-shrink:0;gap:8px;display:flex}.topic-ranking-section__filter{flex-direction:column;gap:2px;min-width:242px;display:flex}.topic-ranking-section__filter-label{font-family:var(--font-second);color:#4e4e4e;font-size:16px;font-weight:400;line-height:24px}.topic-ranking-section__list{flex-direction:column;display:flex}.topic-ranking-section__load-more-btn{font-family:var(--font-first);color:var(--color-first);border:1px solid var(--color-first);cursor:pointer;white-space:nowrap;border-radius:8px;justify-content:center;align-self:center;align-items:center;gap:8px;padding:8px 12px;font-size:18px;font-weight:700;line-height:22px;transition:background-color .2s;display:flex}.topic-ranking-section__load-more-btn:hover{background-color:var(--color-first-alpha)}.topic-ranking-section__load-more-btn .icon--color-default{color:var(--color-first)}.topic-ranking-section__load-more-btn #loading__svg{width:22px;height:22px}.topic-ranking-section__loading{justify-content:center;align-items:center;min-height:200px;display:flex}.topic-ranking-section__empty{font-family:var(--font-second);color:#767676;text-align:center;margin:0;padding:24px 0;font-size:14px}.tutor-usage-stat-card{gap:var(--ui-space-xs);padding:var(--ui-space-xs)var(--ui-space-md);border:var(--ui-stroke-1)solid var(--ui-color-stroke-primary);border-radius:var(--ui-radius-xl);background-color:var(--ui-color-bg-container-primary);flex-direction:column;display:flex}.tutor-usage-stat-card__header{justify-content:space-between;align-items:center;display:flex}.tutor-usage-stat-card__icon{width:var(--ui-size-5xl);height:var(--ui-size-5xl);border-radius:var(--ui-radius-xl);justify-content:center;align-items:center;display:flex}.tutor-usage-stat-card__icon--purple{background-color:var(--ui-color-purple-100)}.tutor-usage-stat-card__icon--purple .icon--color-default{color:var(--ui-color-purple-500)}.tutor-usage-stat-card__icon--blue{background-color:var(--ui-color-blue-100)}.tutor-usage-stat-card__icon--blue .icon--color-default{color:var(--ui-color-blue-500)}.tutor-usage-stat-card__icon--orange{background-color:var(--ui-color-orange-100)}.tutor-usage-stat-card__icon--orange .icon--color-default{color:var(--ui-color-orange-500)}.tutor-usage-stat-card__icon--green{background-color:var(--ui-color-green-100)}.tutor-usage-stat-card__icon--green .icon--color-default{color:var(--ui-color-green-500)}.tutor-usage-stat-card__info-icon{cursor:help;opacity:.5;align-items:center;display:flex}.tutor-usage-stat-card__info-icon:hover{opacity:.8}.tutor-usage-stat-card__label{font-family:var(--ui-font-family-body);font-size:var(--ui-font-size-14);font-weight:var(--ui-font-weight-medium);line-height:var(--ui-line-height-20);color:var(--ui-color-text-secondary);margin:0;margin-top:var(--ui-space-xs)}.tutor-usage-stat-card__value{font-family:var(--ui-font-family-body);font-size:var(--ui-font-size-18);font-weight:var(--ui-font-weight-bold);line-height:var(--ui-line-height-26);color:var(--ui-color-text-default);margin:0}.tutor-usage-stat-card__subtitle{font-family:var(--ui-font-family-body);font-size:var(--ui-font-size-14);font-weight:var(--ui-font-weight-medium);line-height:var(--ui-line-height-20);color:var(--ui-color-text-tertiary);margin:0}.tutor-usage-stat-card__trend{align-items:center;gap:var(--ui-space-xxs);font-family:var(--ui-font-family-body);font-size:var(--ui-font-size-12);font-weight:var(--ui-font-weight-semibold);line-height:var(--ui-line-height-18);margin:0;margin-top:var(--ui-space-xs);display:flex}.tutor-usage-stat-card__trend .icon__wrapper{margin-right:var(--ui-space-xs)}.tutor-usage-stat-card__trend .icon__wrapper svg{width:var(--ui-size-xxl);height:var(--ui-size-xxl)}.tutor-usage-stat-card__trend--positive,.tutor-usage-stat-card__trend--positive .icon--color-success,.tutor-usage-stat-card__trend--positive .tutor-usage-stat-card__trend-text{color:var(--ui-color-green-600)}.tutor-usage-stat-card__trend--negative,.tutor-usage-stat-card__trend--negative .icon--color-red,.tutor-usage-stat-card__trend--negative .tutor-usage-stat-card__trend-text{color:var(--ui-color-red-600)}.tutor-usage-stat-card__trend--neutral,.tutor-usage-stat-card__trend--neutral .tutor-usage-stat-card__trend-text{color:var(--ui-color-text-tertiary)}.tutor-usage-stat-card__trend-text{font-family:var(--ui-font-family-body);font-size:var(--ui-font-size-12);font-weight:var(--ui-font-weight-semibold);color:var(--ui-color-text-tertiary);margin-left:var(--ui-space-xxs)}.tutor-usage-stat-card__trend-text--na{margin-left:0}.prerequisite-list{flex-direction:column;gap:8px;display:flex}.prerequisite-list__description{font-family:var(--font-second);color:#4e4e4e;background-color:#f9f9f9;border-radius:8px;margin:0;padding:8px;font-size:14px;line-height:20px}.prerequisite-list__description strong{font-family:var(--font-second-bold)}.prerequisite-list__items{flex-direction:column;gap:8px;margin:0;padding:0;list-style:none;display:flex}.prerequisite-list__item{flex-direction:column;gap:4px;display:flex}.prerequisite-list__item:not(:last-child){border-bottom:1px solid #e0e0e0;padding-bottom:8px}