:root{--color-primary:#6c5ce7;--color-primary-light:#a29bfe;--color-primary-dark:#4a3fc7;--color-primary-glow:#6c5ce74d;--color-accent-pink:#fd79a8;--color-accent-yellow:#ffeaa7;--color-accent-orange:#fab1a0;--color-accent-green:#55efc4;--color-accent-blue:#74b9ff;--color-accent-cyan:#81ecec;--color-srs-again:#ff6b6b;--color-srs-again-bg:#ff6b6b1f;--color-srs-hard:#ff9f43;--color-srs-hard-bg:#ff9f431f;--color-srs-good:#6bcb77;--color-srs-good-bg:#6bcb771f;--color-srs-easy:#74b9ff;--color-srs-easy-bg:#74b9ff1f;--color-bg:#f8f7ff;--color-bg-card:#fff;--color-bg-secondary:#f0eeff;--color-text:#2d3436;--color-text-secondary:#636e72;--color-text-light:#b2bec3;--color-border:#dfe6e9;--color-shadow:#6c5ce714;--font-en:"Nunito", -apple-system, BlinkMacSystemFont, sans-serif;--font-zh:"Noto Sans TC", -apple-system, BlinkMacSystemFont, sans-serif;--font-size-xs:.75rem;--font-size-sm:.875rem;--font-size-base:1rem;--font-size-lg:1.25rem;--font-size-xl:1.5rem;--font-size-2xl:2rem;--font-size-3xl:2.5rem;--font-size-4xl:3.5rem;--font-size-hero:5rem;--space-xs:.25rem;--space-sm:.5rem;--space-md:1rem;--space-lg:1.5rem;--space-xl:2rem;--space-2xl:3rem;--space-3xl:4rem;--radius-sm:8px;--radius-md:12px;--radius-lg:20px;--radius-xl:28px;--radius-full:50%;--radius-pill:999px;--shadow-sm:0 2px 8px var(--color-shadow);--shadow-md:0 4px 20px var(--color-shadow);--shadow-lg:0 8px 40px var(--color-shadow);--shadow-xl:0 12px 60px #6c5ce726;--shadow-card:0 8px 32px #6c5ce71f;--shadow-button:0 4px 15px #6c5ce740;--transition-fast:.15s ease;--transition-base:.25s ease;--transition-slow:.4s ease;--transition-bounce:.5s cubic-bezier(.34, 1.56, .64, 1);--z-dropdown:100;--z-modal:200;--z-toast:300;--z-navbar:50}*,:before,:after{box-sizing:border-box;margin:0;padding:0}html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;font-size:16px}body{font-family:var(--font-zh);color:var(--color-text);background:var(--color-bg);-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;min-height:100dvh;line-height:1.6;overflow-x:hidden}body:before{content:"";z-index:-1;background:radial-gradient(at 20% 20%,#6c5ce70f 0%,#0000 50%),radial-gradient(at 80% 80%,#fd79a80d 0%,#0000 50%),radial-gradient(#74b9ff0a 0%,#0000 60%);animation:20s ease-in-out infinite alternate bgShift;position:fixed;inset:0}@keyframes bgShift{0%{transform:scale(1)rotate(0)}to{transform:scale(1.1)rotate(2deg)}}#root{flex-direction:column;min-height:100dvh;display:flex}a{color:var(--color-primary);text-decoration:none}img{max-width:100%;height:auto;display:block}.container{width:100%;max-width:1200px;padding:0 var(--space-lg);margin:0 auto}.text-center{text-align:center}.text-gradient{background:linear-gradient(135deg, var(--color-primary), var(--color-accent-pink));-webkit-text-fill-color:transparent;-webkit-background-clip:text;background-clip:text}.btn{justify-content:center;align-items:center;gap:var(--space-sm);padding:var(--space-md) var(--space-xl);border-radius:var(--radius-lg);font-family:var(--font-zh);font-size:var(--font-size-lg);cursor:pointer;transition:all var(--transition-base);-webkit-user-select:none;user-select:none;-webkit-tap-highlight-color:transparent;border:none;min-width:56px;min-height:56px;font-weight:700;display:inline-flex;position:relative;overflow:hidden}.btn:after{content:"";transition:background var(--transition-fast);background:#fff0;position:absolute;inset:0}.btn:active:after{background:#fff3}.btn:active{transform:scale(.96)}.btn-primary{background:linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));color:#fff;box-shadow:var(--shadow-button)}.btn-primary:hover{transform:translateY(-2px);box-shadow:0 6px 25px #6c5ce759}.btn-ghost{background:var(--color-bg-secondary);color:var(--color-primary)}.btn-ghost:hover{background:var(--color-primary-light);color:#fff}.btn-icon{border-radius:var(--radius-full);width:56px;height:56px;font-size:var(--font-size-xl);padding:0}.btn-lg{padding:var(--space-lg) var(--space-2xl);font-size:var(--font-size-xl);border-radius:var(--radius-xl);min-height:64px}.card{background:var(--color-bg-card);border-radius:var(--radius-lg);box-shadow:var(--shadow-card);transition:all var(--transition-base);border:1px solid #6c5ce714;overflow:hidden}.card:hover{box-shadow:var(--shadow-lg)}.card-body{padding:var(--space-xl)}.badge{align-items:center;gap:var(--space-xs);padding:var(--space-xs) var(--space-md);border-radius:var(--radius-pill);font-size:var(--font-size-sm);font-weight:700;display:inline-flex}.badge-primary{background:var(--color-primary-glow);color:var(--color-primary)}.badge-success{background:var(--color-srs-easy-bg);color:#27ae60}.badge-warning{background:var(--color-srs-medium-bg);color:#e67e22}.navbar{z-index:var(--z-navbar);-webkit-backdrop-filter:blur(20px);padding:var(--space-md) 0;background:#f8f7ffd9;border-bottom:1px solid #6c5ce714;position:sticky;top:0}.navbar-inner{max-width:1200px;padding:0 var(--space-lg);justify-content:space-between;align-items:center;margin:0 auto;display:flex}.navbar-logo{align-items:center;gap:var(--space-sm);font-family:var(--font-zh);font-size:var(--font-size-xl);color:var(--color-primary);font-weight:900;display:flex}.logo-cat{border-radius:var(--radius-full);object-fit:cover;width:36px;height:36px;animation:3s ease-in-out infinite logoFloat}@keyframes logoFloat{0%,to{transform:translateY(0)rotate(0)}50%{transform:translateY(-4px)rotate(5deg)}}.navbar-nav{align-items:center;gap:var(--space-sm);display:flex}.nav-link{align-items:center;gap:var(--space-xs);padding:var(--space-sm) var(--space-md);border-radius:var(--radius-md);font-weight:600;font-size:var(--font-size-base);color:var(--color-text-secondary);transition:all var(--transition-fast);cursor:pointer;font-family:var(--font-zh);background:0 0;border:none;display:flex}.nav-link:hover,.nav-link.active{color:var(--color-primary);background:var(--color-primary-glow)}.navbar-user{align-items:center;gap:var(--space-md);display:flex}.navbar-avatar{border-radius:var(--radius-full);border:2px solid var(--color-primary-light);object-fit:cover;width:40px;height:40px}.login-page{padding:var(--space-2xl);flex:1;justify-content:center;align-items:center;min-height:100dvh;display:flex}.login-card{text-align:center;padding:var(--space-3xl);width:100%;max-width:500px;animation:.6s ease-out fadeInUp}.login-hero-image{width:160px;height:160px;margin:0 auto var(--space-lg);animation:3s ease-in-out infinite heroFloat}.login-hero-image .mascot-img{object-fit:contain;filter:drop-shadow(0 8px 20px #ff8c3240);width:100%;height:100%}@keyframes heroFloat{0%,to{transform:translateY(0)rotate(-2deg)scale(1)}50%{transform:translateY(-10px)rotate(2deg)scale(1.03)}}.login-title{font-size:var(--font-size-3xl);margin-bottom:var(--space-sm);font-weight:900;line-height:1.3}.login-subtitle{font-size:var(--font-size-lg);color:var(--color-text-secondary);margin-bottom:var(--space-2xl)}.google-login-btn{justify-content:center;align-items:center;gap:var(--space-md);padding:var(--space-lg) var(--space-2xl);border:2px solid var(--color-border);border-radius:var(--radius-xl);font-size:var(--font-size-xl);color:var(--color-text);cursor:pointer;transition:all var(--transition-base);width:100%;max-width:360px;min-height:64px;font-weight:700;font-family:var(--font-zh);box-shadow:var(--shadow-sm);background:#fff;display:inline-flex}.google-login-btn:hover{border-color:var(--color-primary);box-shadow:var(--shadow-md);transform:translateY(-2px)}.google-login-btn:active{transform:scale(.98)}.google-login-btn .google-icon{width:28px;height:28px}.login-features{gap:var(--space-sm);margin-top:var(--space-2xl);grid-template-columns:repeat(4,1fr);display:grid}.login-feature{text-align:center;padding:var(--space-sm)}.login-feature-icon{margin-bottom:var(--space-xs);font-size:1.8rem}.login-feature-text{font-size:var(--font-size-xs);color:var(--color-text-secondary);font-weight:600}.demo-link{margin-top:var(--space-lg);font-size:var(--font-size-base);color:var(--color-primary);cursor:pointer;text-underline-offset:4px;font-weight:600;font-family:var(--font-zh);background:0 0;border:none;text-decoration:underline}.login-donation{margin-top:var(--space-xl);padding-top:var(--space-lg);border-top:1px solid var(--color-border)}.donation-btn{justify-content:center;align-items:center;gap:var(--space-md);padding:var(--space-md) var(--space-xl);border-radius:var(--radius-lg);color:#4a3500;font-weight:700;font-family:var(--font-zh);transition:all var(--transition-base);background:linear-gradient(135deg,#fd0,#fbb034);text-decoration:none;display:flex;box-shadow:0 4px 15px #fbb0344d}.donation-btn:hover{transform:translateY(-2px);box-shadow:0 6px 25px #fbb03466}.donation-icon{font-size:1.8rem}.donation-text{flex-direction:column;align-items:flex-start;display:flex}.donation-label{font-size:var(--font-size-xs);opacity:.8}.donation-action{font-size:var(--font-size-base);font-family:var(--font-en);font-weight:800}.study-page{padding:var(--space-xl) var(--space-lg);flex-direction:column;flex:1;align-items:center;width:100%;max-width:800px;margin:0 auto;display:flex}.study-progress-bar{background:var(--color-bg-secondary);border-radius:var(--radius-pill);width:100%;height:8px;margin-bottom:var(--space-lg);overflow:hidden}.study-progress-fill{background:linear-gradient(90deg, var(--color-primary), var(--color-accent-pink));border-radius:var(--radius-pill);height:100%;transition:width var(--transition-slow)}.study-info{width:100%;margin-bottom:var(--space-lg);font-size:var(--font-size-sm);color:var(--color-text-secondary);justify-content:space-between;align-items:center;display:flex}.study-info-badge{align-items:center;gap:var(--space-xs);padding:var(--space-xs) var(--space-md);background:var(--color-bg-secondary);border-radius:var(--radius-pill);font-weight:600;display:inline-flex}.flashcard-container{perspective:1500px;aspect-ratio:16/10;width:100%;max-width:820px;max-height:75vh;margin-bottom:var(--space-lg);cursor:pointer}.flashcard{width:100%;height:100%;transform-style:preserve-3d;transition:transform .6s cubic-bezier(.34,1.56,.64,1);position:relative}.flashcard.flipped{transform:rotateY(180deg)}.flashcard-face{backface-visibility:hidden;border-radius:var(--radius-xl);box-shadow:var(--shadow-xl);flex-direction:column;display:flex;position:absolute;inset:0;overflow:hidden}.modern-front{background:#fff;border:none;justify-content:center;align-items:center;box-shadow:0 4px 20px #0000000d}.flashcard-front-center{align-items:center;gap:var(--space-md);margin-bottom:2rem;display:flex}.flashcard-word-large{font-family:var(--font-en);color:#2d3250;font-size:3.2rem;font-weight:600;line-height:1}.inline-audio-btn{cursor:pointer;color:#5b4df0;background:0 0;border:none;border-radius:50%;justify-content:center;align-items:center;width:48px;height:48px;transition:all .2s;display:flex}.inline-audio-btn:hover{color:#4435c4;transform:scale(1.1)}.inline-audio-btn.small{color:#fff;background:#ffffff1a;width:24px;min-width:24px;height:24px;padding:0}.inline-audio-btn.small:hover{background:var(--color-primary)}.inline-audio-btn svg{width:24px;height:24px}.inline-audio-btn.small svg{width:14px;height:14px}.flashcard-front-hint{bottom:var(--space-xl);align-items:center;gap:var(--space-xs);font-size:var(--font-size-sm);color:#aaa;font-weight:600;display:flex;position:absolute}.modern-back{color:#f1f1f1;background:#1e2336;border:none;justify-content:flex-start;transform:rotateY(180deg)}.modern-back .flashcard-hero-image{background:#000;border-bottom:2px solid #ffffff0d;flex:0 0 45%;width:100%;overflow:hidden}.flashcard-image-hero{background:linear-gradient(135deg,#e8e5ff 0%,#fff0f5 50%,#e5f6ff 100%);border-bottom:2px solid #6c5ce714;flex:0 0 55%;justify-content:center;align-items:center;width:100%;display:flex;overflow:hidden}.word-image-ai{object-fit:cover;width:100%;height:100%}.word-image-emoji{justify-content:center;align-items:center;width:100%;height:100%;font-size:6rem;display:flex}.flashcard-back-body{padding:var(--space-sm) var(--space-lg);gap:var(--space-xs);text-align:left;flex-direction:column;flex:1;width:100%;display:flex;overflow-y:auto}.flashcard-vocab-info{font-family:var(--font-en);color:#e2e8f0;font-size:1.15rem;font-weight:500}.flashcard-forms{color:#94a3b8;margin-top:2px;font-size:1.05rem}.flashcard-example-box{margin-top:auto;margin-bottom:var(--space-xs);background:#2a304c;border-radius:8px;align-items:flex-start;gap:12px;padding:14px 16px;display:flex}.flashcard-example-text{font-family:var(--font-en);color:#f1f5f9;font-size:1.2rem;font-weight:400;line-height:1.45}.flashcard-example-trans{font-family:var(--font-zh);color:#94a3b8;margin-top:6px;font-size:1.05rem;display:block}.flashcard-srs-wrapper{padding:0 var(--space-lg) var(--space-lg);width:100%}.flashcard-srs-wrapper .srs-buttons{width:100%;max-width:none;margin:0}.srs-buttons{gap:var(--space-sm);grid-template-columns:repeat(4,1fr);width:100%;max-width:560px;display:grid}.srs-btn{padding:var(--space-md) var(--space-sm);border-radius:var(--radius-lg);font-family:var(--font-en);font-size:var(--font-size-base);cursor:pointer;transition:all var(--transition-bounce);border:3px solid #0000;flex-direction:column;align-items:center;gap:4px;min-height:80px;font-weight:800;display:flex;position:relative;overflow:hidden}.srs-btn:active{transform:scale(.92)}.srs-btn-icon{font-size:1.6rem;line-height:1}.srs-btn-label{font-size:var(--font-size-sm);font-weight:800}.srs-btn-key{font-size:var(--font-size-xs);opacity:.5;background:#0000000f;border-radius:4px;justify-content:center;align-items:center;width:20px;height:20px;margin-top:2px;font-weight:600;display:flex}.srs-btn-again{background:var(--color-srs-again-bg);border-color:var(--color-srs-again);color:#c0392b}.srs-btn-again:hover{background:var(--color-srs-again);color:#fff;transform:translateY(-3px);box-shadow:0 6px 20px #ff6b6b66}.srs-btn-hard{background:var(--color-srs-hard-bg);border-color:var(--color-srs-hard);color:#d35400}.srs-btn-hard:hover{background:var(--color-srs-hard);color:#fff;transform:translateY(-3px);box-shadow:0 6px 20px #ff9f4366}.srs-btn-good{background:var(--color-srs-good-bg);border-color:var(--color-srs-good);color:#27ae60}.srs-btn-good:hover{background:var(--color-srs-good);color:#fff;transform:translateY(-3px);box-shadow:0 6px 20px #6bcb7766}.srs-btn-easy{background:var(--color-srs-easy-bg);border-color:var(--color-srs-easy);color:#2980b9}.srs-btn-easy:hover{background:var(--color-srs-easy);color:#fff;transform:translateY(-3px);box-shadow:0 6px 20px #74b9ff66}.modern-back .srs-btn{border-radius:8px;justify-content:center;align-items:center;min-height:52px;padding:12px 4px;display:flex}.modern-back .srs-btn-icon{display:none}.modern-back .srs-btn-label{letter-spacing:.5px;font-size:1.05rem;font-weight:500}.modern-back .srs-btn-key{display:none}.modern-back .srs-btn-again{color:#ff6b6b;background:#3b2228;border-color:#0000}.modern-back .srs-btn-again:hover{color:#fff;filter:none;box-shadow:none;background:#ff6b6b;transform:none}.modern-back .srs-btn-hard{color:#ff9f43;background:#453020;border-color:#0000}.modern-back .srs-btn-hard:hover{color:#fff;filter:none;box-shadow:none;background:#ff9f43;transform:none}.modern-back .srs-btn-good{color:#4cd137;background:#1c3829;border-color:#0000}.modern-back .srs-btn-good:hover{color:#fff;filter:none;box-shadow:none;background:#4cd137;transform:none}.modern-back .srs-btn-easy{color:#34e7e4;background:#1f304a;border-color:#0000}.modern-back .srs-btn-easy:hover{color:#fff;filter:none;box-shadow:none;background:#34e7e4;transform:none}.study-info-stats{gap:var(--space-sm);display:flex}.mini-stat{font-weight:800;font-family:var(--font-en);font-size:var(--font-size-sm)}.keyboard-help-toggle{margin-top:var(--space-lg);padding:var(--space-xs) var(--space-md);border:1px solid var(--color-border);border-radius:var(--radius-pill);font-size:var(--font-size-xs);color:var(--color-text-light);cursor:pointer;font-family:var(--font-zh);transition:all var(--transition-fast);background:0 0}.keyboard-help-toggle:hover{border-color:var(--color-primary);color:var(--color-primary)}.keyboard-help{gap:var(--space-md);margin-top:var(--space-sm);flex-wrap:wrap;justify-content:center;display:flex}.keyboard-help-item{align-items:center;gap:var(--space-xs);font-size:var(--font-size-xs);color:var(--color-text-secondary);display:flex}.keyboard-help-item kbd{background:var(--color-bg-secondary);border:1px solid var(--color-border);min-width:28px;height:24px;font-family:var(--font-en);border-radius:5px;justify-content:center;align-items:center;padding:0 6px;font-size:.7rem;font-weight:700;display:inline-flex;box-shadow:0 1px 2px #0000001a}.completed-stats{gap:var(--space-md);margin-top:var(--space-md);flex-wrap:wrap;justify-content:center;display:flex}.completed-stat{align-items:center;gap:var(--space-xs);padding:var(--space-sm) var(--space-md);border-radius:var(--radius-pill);font-size:var(--font-size-base);color:var(--stat-color,var(--color-text));background:#00000008;font-weight:700;display:flex}.dashboard-page{padding:var(--space-xl) var(--space-lg);flex:1;width:100%;max-width:1000px;margin:0 auto}.dashboard-title{font-size:var(--font-size-2xl);margin-bottom:var(--space-xl);font-weight:900}.stats-grid{gap:var(--space-lg);margin-bottom:var(--space-2xl);grid-template-columns:repeat(auto-fit,minmax(200px,1fr));display:grid}.stat-card{text-align:center;padding:var(--space-xl);position:relative;overflow:hidden}.stat-card:before{content:"";border-radius:var(--radius-lg) var(--radius-lg) 0 0;height:4px;position:absolute;top:0;left:0;right:0}.stat-card:first-child:before{background:linear-gradient(90deg, var(--color-primary), var(--color-accent-pink))}.stat-card:nth-child(2):before{background:linear-gradient(90deg, var(--color-accent-orange), var(--color-srs-medium))}.stat-card:nth-child(3):before{background:linear-gradient(90deg, var(--color-srs-easy), var(--color-accent-cyan))}.stat-card:nth-child(4):before{background:linear-gradient(90deg, var(--color-accent-blue), var(--color-primary))}.stat-icon{margin-bottom:var(--space-sm);font-size:2.5rem}.stat-value{font-family:var(--font-en);font-size:var(--font-size-3xl);color:var(--color-primary);margin-bottom:var(--space-xs);font-weight:900;line-height:1}.stat-label{font-size:var(--font-size-sm);color:var(--color-text-secondary);font-weight:600}.word-wall{margin-top:var(--space-xl)}.word-wall-title{font-size:var(--font-size-xl);margin-bottom:var(--space-lg);align-items:center;gap:var(--space-sm);font-weight:800;display:flex}.word-wall-grid{gap:var(--space-sm);flex-wrap:wrap;display:flex}.word-wall-item{padding:var(--space-sm) var(--space-md);background:linear-gradient(135deg, var(--color-primary-glow), #fd79a81a);border-radius:var(--radius-pill);font-family:var(--font-en);font-weight:700;font-size:var(--font-size-base);color:var(--color-primary-dark);transition:all var(--transition-fast);cursor:default;border:1px solid #6c5ce726}.word-wall-item:hover{background:var(--color-primary);color:#fff;transform:scale(1.05)}.wordlist-page{padding:var(--space-xl) var(--space-lg);flex:1;width:100%;max-width:1000px;margin:0 auto}.wordlist-header{margin-bottom:var(--space-xl);justify-content:space-between;align-items:center;gap:var(--space-md);flex-wrap:wrap;display:flex}.wordlist-title{font-size:var(--font-size-2xl);font-weight:900}.search-box{align-items:center;gap:var(--space-sm);padding:var(--space-sm) var(--space-lg);background:var(--color-bg-card);border:2px solid var(--color-border);border-radius:var(--radius-pill);transition:border-color var(--transition-fast);min-width:280px;display:flex}.search-box:focus-within{border-color:var(--color-primary);box-shadow:0 0 0 4px var(--color-primary-glow)}.search-box input{font-size:var(--font-size-base);font-family:var(--font-zh);color:var(--color-text);width:100%;padding:var(--space-xs) 0;background:0 0;border:none;outline:none}.search-box input::placeholder{color:var(--color-text-light)}.search-icon{color:var(--color-text-light);font-size:1.3rem}.grade-tabs{gap:var(--space-sm);margin-bottom:var(--space-lg);flex-wrap:wrap;display:flex}.grade-tab{padding:var(--space-sm) var(--space-lg);border:2px solid var(--color-border);border-radius:var(--radius-pill);cursor:pointer;transition:all var(--transition-fast);background:var(--color-bg-card);font-weight:700;font-family:var(--font-zh);font-size:var(--font-size-sm)}.grade-tab:hover{border-color:var(--color-primary)}.grade-tab.active{background:var(--color-primary);color:#fff;border-color:var(--color-primary)}.word-table{border-collapse:separate;width:100%;border-spacing:0 var(--space-sm)}.word-row{background:var(--color-bg-card);border-radius:var(--radius-md);transition:all var(--transition-fast)}.word-row:hover{box-shadow:var(--shadow-md);transform:translateY(-1px)}.word-row td{padding:var(--space-md) var(--space-lg)}.word-row td:first-child{border-radius:var(--radius-md) 0 0 var(--radius-md);font-family:var(--font-en);font-weight:800;font-size:var(--font-size-lg);color:var(--color-primary)}.word-row td:last-child{border-radius:0 var(--radius-md) var(--radius-md) 0}.word-pos{font-size:var(--font-size-xs);color:var(--color-text-light);font-weight:600}.add-word-section{margin-top:var(--space-2xl)}.add-word-form{gap:var(--space-md);grid-template-columns:1fr 1fr;display:grid}.form-group{gap:var(--space-xs);flex-direction:column;display:flex}.form-group.full-width{grid-column:1/-1}.form-label{font-size:var(--font-size-sm);color:var(--color-text-secondary);font-weight:700}.form-input{padding:var(--space-md) var(--space-lg);border:2px solid var(--color-border);border-radius:var(--radius-md);font-size:var(--font-size-base);font-family:var(--font-zh);transition:all var(--transition-fast);background:var(--color-bg-card)}.form-input:focus{border-color:var(--color-primary);box-shadow:0 0 0 4px var(--color-primary-glow);outline:none}.empty-state{text-align:center;padding:var(--space-3xl)}.empty-icon{margin-bottom:var(--space-lg);font-size:4rem}.empty-text{font-size:var(--font-size-lg);color:var(--color-text-secondary);font-weight:600}.loader{border:4px solid var(--color-bg-secondary);border-top-color:var(--color-primary);border-radius:var(--radius-full);width:48px;height:48px;margin:var(--space-2xl) auto;animation:.8s linear infinite spin}@keyframes spin{to{transform:rotate(360deg)}}@keyframes confettiDrop{0%{opacity:1;transform:translateY(-100vh)rotate(0)}to{opacity:0;transform:translateY(100vh)rotate(720deg)}}.confetti-piece{width:10px;height:10px;z-index:var(--z-toast);pointer-events:none;border-radius:2px;animation:3s ease-in forwards confettiDrop;position:fixed;top:0}@keyframes fadeInUp{0%{opacity:0;transform:translateY(30px)}to{opacity:1;transform:translateY(0)}}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}@keyframes slideInRight{0%{opacity:0;transform:translate(40px)}to{opacity:1;transform:translate(0)}}@keyframes slideInLeft{0%{opacity:0;transform:translate(-40px)}to{opacity:1;transform:translate(0)}}@keyframes scaleIn{0%{opacity:0;transform:scale(.8)}to{opacity:1;transform:scale(1)}}.animate-fade-in{animation:.5s ease-out fadeIn}.animate-fade-in-up{animation:.5s ease-out fadeInUp}.animate-slide-right{animation:.5s ease-out slideInRight}.animate-scale-in{animation:scaleIn .4s var(--transition-bounce)}.streak-fire{animation:.5s ease-in-out infinite alternate fireBounce;display:inline-block}@keyframes fireBounce{0%{transform:scale(1)rotate(-3deg)}to{transform:scale(1.1)rotate(3deg)}}@media (width>=768px) and (width<=1024px){:root{--font-size-4xl:3rem;--font-size-3xl:2.2rem}.flashcard-container{max-width:480px}.srs-btn{min-height:90px;padding:var(--space-lg) var(--space-md)}}@media (width>=1024px) and (width<=1366px){.study-page{flex-direction:column}.flashcard-container{max-width:500px}}@media (width<=767px){:root{--font-size-4xl:2.5rem;--font-size-3xl:2rem;--font-size-2xl:1.5rem}.navbar-inner{padding:0 var(--space-md)}.navbar-logo{font-size:var(--font-size-lg)}.nav-link span:not(.nav-icon){display:none}.flashcard-container{aspect-ratio:3/4.2;max-width:380px}.flashcard-word{font-size:var(--font-size-3xl)}.srs-buttons{gap:4px}.srs-btn{padding:var(--space-sm);min-height:70px}.srs-btn-label{font-size:var(--font-size-xs)}.srs-btn-key{display:none}.login-features,.stats-grid{grid-template-columns:repeat(2,1fr)}.login-features{gap:var(--space-sm);grid-template-columns:repeat(3,1fr)}.login-card{padding:var(--space-xl)}.add-word-form{grid-template-columns:1fr}.search-box{min-width:100%}}@media (width>=1366px){.container{max-width:1200px}}.toast{bottom:var(--space-2xl);background:var(--color-primary);color:#fff;padding:var(--space-md) var(--space-xl);border-radius:var(--radius-pill);box-shadow:var(--shadow-lg);z-index:var(--z-toast);transition:transform var(--transition-bounce);pointer-events:none;font-weight:700;position:fixed;left:50%;transform:translate(-50%)translateY(100px)}.toast.show{transform:translate(-50%)translateY(0)}.completed-overlay{z-index:var(--z-modal);background:#f8f7fff2;flex-direction:column;justify-content:center;align-items:center;animation:.5s ease-out fadeIn;display:flex;position:fixed;inset:0}.completed-icon{margin-bottom:var(--space-lg);animation:scaleIn .5s var(--transition-bounce);font-size:6rem}.completed-title{font-size:var(--font-size-3xl);margin-bottom:var(--space-md);font-weight:900}.completed-subtitle{font-size:var(--font-size-lg);color:var(--color-text-secondary);margin-bottom:var(--space-2xl)}.payment-modal-overlay{z-index:9999;-webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px);padding:var(--space-md);background:#0009;justify-content:center;align-items:center;animation:.2s fadeIn;display:flex;position:fixed;inset:0}.payment-modal{border-radius:var(--radius-2xl);padding:var(--space-2xl) var(--space-xl);width:100%;max-width:440px;animation:slideUp .35s var(--transition-bounce);background:linear-gradient(145deg,#fffffff2,#f5f0fffa);border:1px solid #6c5ce733;position:relative;box-shadow:0 25px 60px #00000080,0 0 40px #6c5ce726}.payment-modal-close{top:var(--space-md);right:var(--space-md);color:var(--color-text-secondary);cursor:pointer;background:#6c5ce714;border:none;border-radius:50%;justify-content:center;align-items:center;width:36px;height:36px;font-size:1.2rem;transition:all .2s;display:flex;position:absolute}.payment-modal-close:hover{color:var(--color-primary);background:#6c5ce726}.payment-modal-icon{text-align:center;margin-bottom:var(--space-md);animation:scaleIn .4s var(--transition-bounce);font-size:4rem}.payment-modal-title{text-align:center;font-size:var(--font-size-xl);margin-bottom:var(--space-lg);font-weight:900;line-height:1.4}.payment-modal-body{text-align:center;color:var(--color-text-secondary);font-size:var(--font-size-md);line-height:1.7}.payment-modal-email{margin:var(--space-lg) 0;padding:var(--space-md);border-radius:var(--radius-lg);background:#6c5ce71a;border:1px solid #6c5ce740}.payment-modal-email-value{color:var(--color-primary-light);font-weight:700;font-size:var(--font-size-md);margin-top:var(--space-xs);word-break:break-all}.payment-modal-benefits{gap:var(--space-xs);margin:var(--space-lg) 0;text-align:left;display:grid}.payment-benefit{padding:var(--space-sm) var(--space-md);border-radius:var(--radius-md);font-size:var(--font-size-sm);color:var(--color-text);background:#6c5ce70d;border:1px solid #6c5ce726;font-weight:500}.payment-modal-btn{width:100%;margin-top:var(--space-md);font-size:var(--font-size-lg)!important;padding:var(--space-md) var(--space-xl)!important}.grade-tab.locked{opacity:.55;position:relative}.grade-tab.locked:hover{opacity:.8;background:#fd79a814;border-color:#fd79a866}@keyframes slideUp{0%{opacity:0;transform:translateY(30px)scale(.95)}to{opacity:1;transform:translateY(0)scale(1)}}