:root{color-scheme:dark}[hidden]{display:none!important}.button-row{display:flex;flex-wrap:wrap;gap:10px;align-items:center}.app-button{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:42px;padding:9px 16px;border-radius:var(--radius-md);cursor:pointer;font-weight:700;color:var(--color-text);background:var(--color-surface-secondary);transition:.18s ease}.app-button:hover{transform:translateY(-1px);background:var(--color-surface-hover)}.app-button--primary{color:#fff;background:var(--gradient-primary)}.app-button--danger{color:var(--color-danger);background:rgba(239,98,108,.12)}.app-button--ghost{background:transparent;border:1px solid var(--color-border)}.app-button:disabled{opacity:.55;cursor:not-allowed;transform:none}.app-field{display:flex;flex-direction:column;gap:7px}.app-field label{font-size:.84rem;font-weight:650;color:var(--color-text-secondary)}.app-field input,.app-field textarea,.app-field select{width:100%;padding:11px 13px;color:var(--color-text);background:var(--color-surface-secondary);border:1px solid var(--color-border);border-radius:var(--radius-md);outline:none}.app-field input:focus,.app-field textarea:focus,.app-field select:focus{border-color:var(--color-primary);box-shadow:0 0 0 3px var(--color-primary-soft)}.auth-form{display:flex;flex-direction:column;gap:16px}.auth-form__alert,.alert{padding:11px 13px;border-radius:var(--radius-md);color:#ffadb3;background:rgba(239,98,108,.1);border:1px solid rgba(239,98,108,.25)}.auth-page__card{width:min(100%,440px);padding:28px;background:var(--color-surface);border:1px solid var(--color-border);border-radius:var(--radius-xl)}.auth-page__card h1{margin:0;font-size:1.65rem}.auth-page__card>p{margin:4px 0 22px;color:var(--color-text-secondary)}.auth-page__footer{text-align:center;color:var(--color-text-secondary);font-size:.9rem}.auth-page__footer a{color:var(--color-primary);font-weight:700}.native-landing{overflow:hidden}.landing-header{height:72px;display:flex;align-items:center;justify-content:space-between}.brand{display:flex;align-items:center;gap:10px;font-size:1.25rem;font-weight:850}.brand span span{color:var(--color-primary)}.brand__icon{width:38px;height:38px;display:grid;place-items:center;border-radius:11px;color:#fff;background:var(--gradient-primary)}.hero{min-height:calc(100vh - 72px);display:grid;place-items:center;padding:70px 0}.hero__container{display:grid;grid-template-columns:1.05fr .95fr;gap:70px;align-items:center}.hero__badge{display:inline-flex;align-items:center;gap:9px;padding:7px 11px;border:1px solid var(--color-border);border-radius:99px;color:var(--color-text-secondary);font-size:.8rem}.hero__badge-dot{width:7px;height:7px;border-radius:50%;background:#56d69b;box-shadow:0 0 12px #56d69b}.hero__title{margin:20px 0 18px;font-size:clamp(2.5rem,6vw,4.8rem);line-height:1.03;letter-spacing:-.055em}.hero__description{max-width:620px;color:var(--color-text-secondary);font-size:1.08rem}.hero__actions{margin:28px 0}.preview-card{padding:24px;border:1px solid var(--color-border);border-radius:24px;background:linear-gradient(145deg,var(--color-surface),rgba(124,92,255,.08));box-shadow:0 30px 90px rgba(0,0,0,.35)}.preview-card__top{display:flex;justify-content:space-between;color:var(--color-text-muted);font-size:.8rem}.preview-card h3{margin:35px 0 20px}.preview-answer{margin:9px 0;padding:12px;border:1px solid var(--color-border);border-radius:10px;color:var(--color-text-secondary)}.preview-answer--active{border-color:var(--color-primary);background:var(--color-primary-soft);color:var(--color-text)}.landing-section{padding:90px 0}.landing-section__intro{max-width:680px;margin-bottom:34px}.landing-section h2{margin:8px 0;font-size:clamp(2rem,4vw,3rem);line-height:1.1}.feature-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}.feature-card-native{padding:22px;background:var(--color-surface);border:1px solid var(--color-border);border-radius:var(--radius-lg)}.feature-card-native h3{margin:8px 0}.feature-card-native p{margin:0;color:var(--color-text-secondary);font-size:.9rem}.privacy-panel{display:grid;grid-template-columns:1fr 1fr;gap:30px;padding:36px;border:1px solid var(--color-border);background:var(--color-surface);border-radius:24px}.privacy-panel li{margin:12px 0;color:var(--color-text-secondary)}.app-shell__user-info span{overflow:hidden;text-overflow:ellipsis}.app-nav{display:flex;flex-direction:column;gap:6px}.app-nav__item{display:flex;align-items:center;gap:11px;padding:10px 12px;border-radius:10px;color:var(--color-text-secondary);font-weight:650}.app-nav__item:hover,.app-nav__item--active{color:var(--color-text);background:var(--color-surface-secondary)}.app-shell__brand-icon{display:grid;place-items:center}.app-shell__logout{cursor:pointer}.app-shell__bottom-nav .app-nav{flex-direction:row}.app-shell__bottom-nav .app-nav__item{flex:1;justify-content:center;font-size:.76rem}.page-header-row{display:flex;align-items:flex-start;justify-content:space-between;gap:18px}.aulas-page__list{display:flex;flex-direction:column;gap:10px}.aula-card{cursor:pointer}.aula-card__body p{margin:0}.empty-state-native{text-align:center;padding:55px 20px;color:var(--color-text-secondary);border:1px dashed var(--color-border);border-radius:var(--radius-lg)}.empty-state-native h3{color:var(--color-text);margin:10px 0 4px}.loading-native{padding:40px;text-align:center;color:var(--color-text-secondary)}.aula-detail__header h1{margin:0}.aula-detail__header p{margin:3px 0 0;color:var(--color-text-secondary)}.detail-section{margin-top:28px}.section-heading{display:flex;justify-content:space-between;align-items:center;gap:12px;margin-bottom:13px}.section-heading h2{margin:0;font-size:1.1rem}.topic-item__body p{margin:0}.aula-detail__topics-list,.aula-documents__list{display:flex;flex-direction:column;gap:8px}.topic-item__action{cursor:pointer}.topic-study-link{color:var(--color-primary);font-size:.8rem;font-weight:700;margin-top:3px}.document-item{display:flex;align-items:center;gap:12px;padding:13px 15px;background:var(--color-surface);border:1px solid var(--color-border);border-radius:var(--radius-md)}.document-item__body{flex:1;min-width:0}.document-item__body strong,.document-item__body span{display:block;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.document-item__body span{color:var(--color-text-muted);font-size:.8rem}.document-item__delete{cursor:pointer;color:var(--color-danger);background:transparent}.document-uploader__dropzone{display:block;text-align:center;cursor:pointer}.document-uploader__input{position:absolute;opacity:0;pointer-events:none}.document-uploader__privacy{color:var(--color-text-muted);font-size:.8rem}.upload-status{margin-top:12px;padding:12px;border-radius:10px;background:var(--color-surface-secondary);color:var(--color-text-secondary)}.upload-progress{height:7px;background:var(--color-border);border-radius:99px;overflow:hidden;margin-top:9px}.upload-progress>div{height:100%;background:var(--gradient-primary);transition:width .2s}.modal-backdrop{position:fixed;inset:0;z-index:1000;display:grid;place-items:center;padding:20px;background:rgba(3,4,8,.75);backdrop-filter:blur(5px)}.modal-native{width:min(100%,500px);max-height:calc(100vh - 40px);overflow:auto;padding:24px;background:var(--color-surface);border:1px solid var(--color-border);border-radius:var(--radius-xl)}.modal-native h2{margin:0 0 4px}.modal-native>p{color:var(--color-text-secondary)}.modal-native .button-row{justify-content:flex-end;margin-top:20px}.toast-region{position:fixed;right:18px;bottom:18px;z-index:2000;display:flex;flex-direction:column;gap:8px}.toast{max-width:360px;padding:12px 15px;border:1px solid var(--color-border);border-radius:10px;background:var(--color-surface);box-shadow:0 12px 40px rgba(0,0,0,.35)}.toast--error{border-color:rgba(239,98,108,.4)}.settings-page__card{padding:24px;background:var(--color-surface);border:1px solid var(--color-border);border-radius:var(--radius-lg)}.settings-page__account{display:grid;grid-template-columns:auto 1fr;gap:8px 24px}.settings-page__account dt{color:var(--color-text-muted)}.settings-page__account dd{margin:0}.study-placeholder{padding:40px;text-align:center;background:var(--color-surface);border:1px solid var(--color-border);border-radius:var(--radius-lg)}
@media(max-width:900px){.hero__container,.privacy-panel{grid-template-columns:1fr}.hero__preview{display:none}.feature-grid{grid-template-columns:repeat(2,1fr)}}@media(max-width:640px){.landing-header nav .app-button--ghost{display:none}.hero{padding:35px 0}.feature-grid{grid-template-columns:1fr}.landing-section{padding:60px 0}.page-header-row{align-items:stretch;flex-direction:column}.page-header-row .app-button{width:100%}.auth-page__card{padding:22px}.topic-item{align-items:flex-start}.topic-item__actions{flex-wrap:wrap;justify-content:flex-end}.document-uploader__dropzone{padding:22px 14px}}

/* =========================================================
   ICON SYSTEM
   ========================================================= */
.ui-icon {
    width: 20px;
    height: 20px;
    display: block;
    flex: 0 0 auto;
    fill: none;
    stroke: currentColor;
    stroke-width: 1.8;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.app-button .ui-icon { width: 18px; height: 18px; }
.app-shell__logout .ui-icon { width: 19px; height: 19px; }
.topic-item__action .ui-icon { width: 17px; height: 17px; }
.document-item__icon .ui-icon { width: 21px; height: 21px; }
.topic-study-link { display: inline-flex; align-items: center; gap: 2px; }
.topic-study-link .ui-icon { width: 14px; height: 14px; }
.aula-card__chevron { color: var(--color-text-muted); }

.document-item__actions { display: flex; flex: 0 0 auto; gap: 4px; }
.document-item__action { width: 36px; height: 36px; display: grid; place-items: center; cursor: pointer; color: var(--color-text-muted); background: transparent; border-radius: 10px; }
.document-item__action:hover { color: var(--color-text); background: var(--color-surface-secondary); }
.document-item__action--danger:hover { color: var(--color-danger); background: rgba(239,98,108,.1); }
.document-item__action .ui-icon { width: 17px; height: 17px; }
.aula-card__chevron .ui-icon { width: 18px; height: 18px; }
.empty-state-native__icon { width: 52px; height: 52px; display: grid; place-items: center; margin: 0 auto 12px; border-radius: 15px; color: var(--color-primary); background: var(--color-primary-soft); }
.empty-state-native__icon .ui-icon { width: 25px; height: 25px; }

.feature-card-native {
    position: relative;
    overflow: hidden;
    transition: transform var(--transition-normal), border-color var(--transition-normal), background var(--transition-normal);
}
.feature-card-native:hover { transform: translateY(-3px); border-color: var(--color-primary-border); background: var(--color-surface-secondary); }
.feature-card-native__icon { width: 42px; height: 42px; display: grid; place-items: center; margin-bottom: 16px; color: var(--color-primary); background: var(--color-primary-soft); border: 1px solid var(--color-primary-border); border-radius: 12px; }
.feature-card-native__icon .ui-icon { width: 21px; height: 21px; }

/* =========================================================
   NAVIGATION
   ========================================================= */
.app-nav--sidebar .app-nav__item { min-height: 44px; }
.app-nav--sidebar .app-nav__icon { display: grid; place-items: center; }
.app-nav--sidebar .app-nav__icon .ui-icon { width: 20px; height: 20px; }
.app-nav--sidebar .app-nav__item.active { color: var(--color-primary); background: var(--color-primary-soft); }

.app-nav--bottom { min-height: 68px; padding: 4px 8px; gap: 4px; }
.app-nav--bottom .app-nav__item {
    min-height: 60px;
    padding: 6px 8px 5px;
    flex-direction: column;
    gap: 3px;
    border-radius: 12px;
    touch-action: manipulation;
}
.app-nav--bottom .app-nav__item span { display: grid; }
.app-nav--bottom .app-nav__icon { width: 28px; height: 28px; place-items: center; }
.app-nav--bottom .app-nav__icon .ui-icon { width: 23px; height: 23px; }
.app-nav--bottom .app-nav__label { display: block; font-size: .68rem; font-weight: 680; line-height: 1; letter-spacing: .01em; }
.app-nav--bottom .app-nav__item.active { color: var(--color-primary); background: var(--color-primary-soft); }
.app-nav--bottom .app-nav__item.active::after { display: none; }

/* =========================================================
   MOBILE POLISH
   ========================================================= */
@media (max-width: 640px) {
    .container { width: min(calc(100% - 28px), var(--container-width)); }
    .landing-header { height: 66px; gap: 10px; }
    .landing-header__actions { flex-wrap: nowrap; gap: 6px; }
    .landing-header__actions .app-button { min-height: 39px; padding: 7px 11px; font-size: .78rem; white-space: nowrap; }
    .landing-header nav .app-button.app-button--ghost { display: inline-flex; }
    .brand { gap: 7px; font-size: 1.02rem; }
    .brand__icon { width: 34px; height: 34px; border-radius: 10px; font-size: .9rem; }
    .hero { min-height: auto; padding: 52px 0 68px; }
    .hero__title { margin-top: 18px; font-size: clamp(2.55rem, 13.5vw, 3.5rem); }
    .hero__description { font-size: .98rem; line-height: 1.65; }
    .hero__actions { align-items: stretch; }
    .hero__actions .app-button { flex: 1; }
    .landing-section__intro { margin-bottom: 24px; }
    .privacy-panel { padding: 24px 20px; }
    .app-shell__topbar { height: 60px; padding-inline: 14px; }
    .app-shell__content { padding: 20px 14px calc(88px + env(safe-area-inset-bottom)); }
    .app-shell__bottom-nav { padding: 0 max(4px, env(safe-area-inset-left)) env(safe-area-inset-bottom) max(4px, env(safe-area-inset-right)); }
    .app-shell__logout--mobile { width: 42px; height: 42px; }
    .topic-item__action { width: 38px; height: 38px; }
    .document-item__action { width: 40px; height: 40px; }
    .document-item__delete { width: 40px; height: 40px; display: grid; place-items: center; border-radius: 10px; }
}

@media (max-width: 350px) {
    .landing-header .brand > span:last-child { display: none; }
    .landing-header__actions .app-button { padding-inline: 9px; }
}

/* =========================================================
   CUSTOM ICON PICKER
   ========================================================= */
.icon-picker { min-width: 0; margin: 0; padding: 0; border: 0; }
.icon-picker legend { margin-bottom: 8px; color: var(--color-text-secondary); font-size: .84rem; font-weight: 650; }
.icon-picker__grid { display: grid; grid-template-columns: repeat(6, minmax(0, 1fr)); gap: 7px; }
.icon-picker__option { cursor: pointer; }
.icon-picker__option input { position: absolute; opacity: 0; pointer-events: none; }
.icon-picker__option > span { min-height: 54px; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 3px; color: var(--color-text-muted); background: var(--color-surface-secondary); border: 1px solid var(--color-border); border-radius: 11px; transition: .16s ease; }
.icon-picker__option small { max-width: 100%; overflow: hidden; font-size: .58rem; text-overflow: ellipsis; white-space: nowrap; }
.icon-picker__option:hover > span { color: var(--color-text); border-color: var(--color-border-hover); }
.icon-picker__option input:focus-visible + span { outline: 2px solid var(--color-primary); outline-offset: 2px; }
.icon-picker__option input:checked + span { color: var(--color-primary); background: var(--color-primary-soft); border-color: var(--color-primary); box-shadow: 0 0 0 2px rgba(124,92,255,.12); }
.icon-picker__option .ui-icon { width: 20px; height: 20px; }

/* =========================================================
   TOPICS, SUBTOPICS AND SORTING
   ========================================================= */
.aula-detail__title { display: flex; align-items: center; gap: 13px; margin-top: 10px; }
.aula-detail__title-icon { width: 44px; height: 44px; display: grid; place-items: center; flex: 0 0 auto; color: var(--color-primary); background: var(--color-primary-soft); border: 1px solid var(--color-primary-border); border-radius: 13px; }
.aula-detail__title-icon .ui-icon { width: 23px; height: 23px; }
.section-heading__hint { margin: 3px 0 0; color: var(--color-text-muted); font-size: .78rem; }
.topic-sort-list { display: flex; flex-direction: column; gap: 9px; min-height: 4px; border-radius: 14px; transition: background .16s ease; }
.topic-sort-list--children { margin: 8px 0 2px 34px; padding-left: 15px; border-left: 1px solid var(--color-primary-border); }
.topic-sort-list.drag-over { background: rgba(124,92,255,.055); }
.topic-node { border-radius: var(--radius-md); }
.topic-node.dragging { opacity: .45; }
.topic-node--child .topic-item { background: var(--color-background-elevated); }
.topic-item__drag { width: 25px; height: 38px; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 3px; flex: 0 0 auto; padding: 0; color: var(--color-text-muted); background: transparent; cursor: grab; }
.topic-item__drag:active { cursor: grabbing; }
.topic-item__drag span { width: 3px; height: 3px; background: currentColor; border-radius: 50%; box-shadow: 6px 0 currentColor; }
.topic-item__icon { width: 36px; height: 36px; display: grid; place-items: center; flex: 0 0 auto; color: var(--color-primary); background: var(--color-primary-soft); border-radius: 10px; }
.topic-item__icon .ui-icon { width: 18px; height: 18px; }
.topic-node--child .topic-item__icon { width: 32px; height: 32px; }
.topic-node--child .topic-item__number { color: var(--color-info); }

/* =========================================================
   PROFILE AND SECURITY
   ========================================================= */
.settings-grid { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 18px; }
.settings-page__card { min-width: 0; }
.settings-card__heading { display: flex; align-items: flex-start; gap: 12px; margin-bottom: 22px; }
.settings-card__heading > span { width: 40px; height: 40px; display: grid; place-items: center; flex: 0 0 auto; color: var(--color-primary); background: var(--color-primary-soft); border-radius: 11px; }
.settings-card__heading h2,.settings-page__card--session h2 { margin: 0; font-size: 1.05rem; }
.settings-card__heading p,.settings-page__card--session p { margin: 2px 0 0; color: var(--color-text-muted); font-size: .8rem; }
.settings-page__card--session { grid-column: 1 / -1; display: flex; align-items: center; justify-content: space-between; gap: 16px; }

@media (max-width: 720px) {
    .settings-grid { grid-template-columns: 1fr; }
    .settings-page__card--session { grid-column: auto; align-items: stretch; flex-direction: column; }
    .icon-picker__grid { grid-template-columns: repeat(4, minmax(0,1fr)); }
    .topic-sort-list--children { margin-left: 18px; padding-left: 9px; }
    .topic-item { gap: 8px; padding: 11px 10px; flex-wrap: wrap; }
    .topic-item__drag { width: 17px; }
    .topic-item__actions { width: 100%; padding-top: 6px; justify-content: flex-end; border-top: 1px solid var(--color-border); }
    .topic-item__body { min-width: calc(100% - 82px); }
}