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var(--border-light);font-size:13px;font-weight:600;color:var(--navy-700);transition:all .15s ease}.topic-tab:hover{background:var(--gray-50)}.topic-tab.active{background:var(--sky-600);color:#fff;border-color:var(--sky-600);box-shadow:0 2px 6px #0284c740}.sentence-card{background:#fff;border-radius:var(--radius-lg);border:1px solid var(--border-light);padding:24px;margin-bottom:16px;box-shadow:var(--shadow-sm);transition:all .2s ease}.sentence-card:hover{border-color:var(--sky-400);box-shadow:var(--shadow-md)}.sentence-english{font-size:18px;font-weight:700;color:var(--navy-900);line-height:1.4;margin-bottom:6px}.sentence-vietnamese{font-size:15px;color:var(--sky-600);font-weight:500;line-height:1.4;margin-bottom:14px}.sentence-vocab-chips{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:14px}.vocab-chip{background:var(--gray-100);padding:4px 10px;border-radius:var(--radius-md);font-size:12px;color:var(--navy-800)}.vocab-chip 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th{padding:12px 16px;background:var(--gray-50);color:var(--text-muted);font-weight:600;border-bottom:1px solid var(--border-light)}.history-table td{padding:14px 16px;border-bottom:1px solid var(--border-light);color:var(--navy-800)}.modal-backdrop{position:fixed;top:0;left:0;right:0;bottom:0;background:#0f172a99;-webkit-backdrop-filter:blur(4px);backdrop-filter:blur(4px);z-index:1000;display:flex;align-items:center;justify-content:center;padding:20px;animation:fadeIn .2s ease}.modal-card{background:#fff;border-radius:var(--radius-lg);max-width:480px;width:100%;box-shadow:var(--shadow-xl);overflow:hidden;animation:scaleUp .2s ease}.modal-header{padding:20px 24px;border-bottom:1px solid var(--border-light);display:flex;align-items:center;justify-content:space-between}.modal-title{font-size:18px;font-weight:700;color:var(--navy-900)}.modal-close-btn{font-size:22px;color:var(--gray-400);line-height:1}.modal-body{padding:24px;font-size:14px;color:var(--navy-700);line-height:1.6}.modal-footer{padding:16px 24px;background:var(--gray-50);border-top:1px solid var(--border-light);display:flex;justify-content:flex-end;gap:12px}.toast-container{position:fixed;bottom:24px;right:24px;z-index:2000;display:flex;flex-direction:column;gap:8px;pointer-events:none}.toast{background:var(--navy-900);color:#fff;padding:12px 18px;border-radius:var(--radius-md);box-shadow:var(--shadow-lg);display:flex;align-items:center;gap:10px;font-size:13px;font-weight:500;opacity:0;transform:translateY(12px);transition:all .25s ease}.toast.toast-visible{opacity:1;transform:translateY(0)}.toast-success{border-left:4px solid var(--emerald-500)}.toast-warning{border-left:4px solid var(--amber-500)}.toast-error{border-left:4px solid var(--rose-500)}.toast-info{border-left:4px solid var(--sky-400)}.bottom-nav{display:none;position:fixed;bottom:0;left:0;right:0;height:var(--bottom-nav-height);background:#fff;border-top:1px solid var(--border-light);z-index:100;justify-content:space-around;align-items:center}.bottom-nav-item{display:flex;flex-direction:column;align-items:center;gap:3px;font-size:10px;font-weight:600;color:var(--gray-400);padding:6px 10px}.bottom-nav-item.active{color:var(--sky-600)}.bottom-nav-item svg{width:22px;height:22px}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}@keyframes scaleUp{0%{transform:scale(.95);opacity:0}to{transform:scale(1);opacity:1}}@media (max-width: 992px){.sidebar{transform:translate(-100%)}.sidebar.open{transform:translate(0)}.main-content{margin-left:0;padding-bottom:calc(var(--bottom-nav-height) + 16px)}.mobile-menu-toggle{display:inline-flex}.bottom-nav{display:flex}.dashboard-columns{grid-template-columns:1fr}}@media (max-width: 640px){.page-container{padding:16px}.hero-banner{padding:24px 20px}.hero-title{font-size:20px}.flashcard-inner{min-height:320px}.flashcard-term-large{font-size:36px}.top-header{padding:0 16px}}