@import "https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap";:root{--color-dark-navy:#0f1729;--color-medium-navy:#1a2332;--color-light-navy:#243447;--color-white:#fff;--color-light-gray:#f0f2f5;--color-medium-gray:#8892a4;--color-accent-gold:#f59e0b;--color-accent-gold-hover:#d97706;--color-success:#10b981;--color-danger:#ef4444;--color-danger-hover:#dc2626;--color-blue:#3b82f6;--color-blue-hover:#2563eb;--font-primary:"Inter", sans-serif;--radius-sm:8px;--radius-md:12px;--radius-lg:16px;--radius-xl:20px;--shadow-subtle:0 1px 3px #0000000f, 0 1px 2px #0000000a;--shadow-medium:0 4px 12px #00000014, 0 2px 6px #0000000f;--shadow-large:0 12px 40px #0000001f, 0 4px 16px #00000014}*,:before,:after{box-sizing:border-box;margin:0;padding:0}body{background-color:var(--color-light-gray);font-family:var(--font-primary);color:var(--color-medium-navy);-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;min-height:100vh;font-size:16px;line-height:1.6}::-webkit-scrollbar{width:6px;height:6px}::-webkit-scrollbar-track{background:0 0}::-webkit-scrollbar-thumb{background-color:var(--color-medium-gray);border-radius:3px}::-webkit-scrollbar-thumb:hover{background-color:var(--color-light-navy)}*{scrollbar-width:thin;scrollbar-color:var(--color-medium-gray) transparent}.auth-container{background:linear-gradient(135deg, var(--color-dark-navy) 0%, var(--color-medium-navy) 100%);justify-content:center;align-items:center;min-height:100vh;padding:20px;display:flex}.auth-card{background:var(--color-white);border-radius:var(--radius-xl);width:100%;max-width:440px;box-shadow:var(--shadow-large);padding:48px}.auth-logo{text-align:center;margin-bottom:32px}.auth-logo h1{color:var(--color-dark-navy);font-size:28px;font-weight:700}.auth-logo p{color:var(--color-medium-gray);margin-top:6px;font-size:15px}.auth-form{flex-direction:column;gap:20px;display:flex}.form-group{flex-direction:column;gap:8px;display:flex}.form-group label{color:var(--color-light-navy);font-size:14px;font-weight:600}.form-group input{border-radius:var(--radius-md);font-size:16px;font-family:var(--font-primary);color:var(--color-medium-navy);background:var(--color-white);border:2px solid #e2e8f0;outline:none;padding:14px 16px;transition:border-color .2s,box-shadow .2s}.form-group input::placeholder{color:var(--color-medium-gray)}.form-group input:focus{border-color:var(--color-blue);box-shadow:0 0 0 3px #3b82f626}.btn-primary{background-color:var(--color-blue);width:100%;color:var(--color-white);font-size:16px;font-weight:600;font-family:var(--font-primary);border-radius:var(--radius-md);cursor:pointer;border:none;padding:14px;transition:background-color .2s,transform .15s}.btn-primary:hover{background-color:var(--color-blue-hover);transform:scale(1.01)}.btn-primary:disabled{opacity:.6;cursor:not-allowed;transform:none}.auth-footer{text-align:center;color:var(--color-medium-gray);margin-top:24px;font-size:14px}.auth-footer a{color:var(--color-blue);font-weight:500;text-decoration:none}.auth-footer a:hover{text-decoration:underline}.auth-error{color:var(--color-danger);border-radius:var(--radius-sm);border-left:4px solid var(--color-danger);background-color:#fef2f2;padding:12px 16px;font-size:14px}.navbar{background-color:var(--color-dark-navy);z-index:100;justify-content:space-between;align-items:center;height:64px;padding:0 32px;display:flex;position:sticky;top:0}.navbar-brand{color:var(--color-white);align-items:center;gap:8px;font-size:20px;font-weight:700;text-decoration:none;display:flex}.navbar-brand:before{content:"⚡";font-size:20px}.navbar-links{align-items:center;gap:8px;display:flex}.navbar-links a{color:var(--color-medium-gray);border-radius:var(--radius-sm);align-items:center;gap:6px;padding:8px 16px;font-size:14px;font-weight:500;text-decoration:none;transition:color .2s,background-color .2s;display:flex}.navbar-links a:hover{color:var(--color-white);background-color:#ffffff14}.navbar-links a.active{color:var(--color-white);background-color:#ffffff1f}.btn-logout{color:var(--color-medium-gray);border-radius:var(--radius-sm);cursor:pointer;font-size:14px;font-family:var(--font-primary);background:0 0;border:1px solid #fff3;align-items:center;gap:6px;padding:8px 16px;transition:color .2s,border-color .2s;display:flex}.btn-logout:hover{color:var(--color-white);border-color:#fff6}.dashboard{max-width:1200px;margin:0 auto;padding:32px}.dashboard-header{justify-content:space-between;align-items:center;margin-bottom:32px;display:flex}.dashboard-header h1{color:var(--color-dark-navy);font-size:28px;font-weight:700}.dashboard-stats{gap:12px;display:flex}.stat-badge{background:var(--color-white);border-radius:var(--radius-xl);box-shadow:var(--shadow-subtle);color:var(--color-medium-gray);padding:8px 16px;font-size:14px;font-weight:500}.stat-badge strong{color:var(--color-blue)}.section{margin-bottom:40px}.section-header{justify-content:space-between;align-items:center;margin-bottom:20px;display:flex}.section-header h2{color:var(--color-medium-navy);font-size:20px;font-weight:600}.btn-add{background-color:var(--color-blue);color:var(--color-white);font-size:14px;font-weight:500;font-family:var(--font-primary);cursor:pointer;border:none;border-radius:10px;align-items:center;gap:8px;padding:10px 20px;transition:background-color .2s;display:flex}.btn-add:hover{background-color:var(--color-blue-hover)}.categories-grid{grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:16px;display:grid}.category-card{background:var(--color-white);border-radius:var(--radius-lg);box-shadow:var(--shadow-subtle);padding:24px;transition:transform .2s,box-shadow .2s;position:relative;overflow:hidden}.category-card:hover{box-shadow:var(--shadow-medium);transform:translateY(-2px)}.category-color-bar{border-radius:4px 4px 0 0;height:4px;position:absolute;top:0;left:0;right:0}.category-card h3{color:var(--color-dark-navy);margin-bottom:8px;font-size:18px;font-weight:600}.category-card .card-count{color:var(--color-medium-gray);margin-bottom:16px;font-size:14px}.category-actions{gap:8px;display:flex}.btn-icon{border-radius:var(--radius-sm);background:var(--color-white);cursor:pointer;width:36px;height:36px;color:var(--color-medium-gray);border:1px solid #e2e8f0;justify-content:center;align-items:center;font-size:16px;transition:background-color .2s,border-color .2s,color .2s;display:flex}.btn-icon:hover{background-color:var(--color-light-gray)}.btn-icon.delete:hover{color:var(--color-danger);background-color:#fef2f2;border-color:#fecaca}.flashcards-filter{flex-wrap:wrap;gap:12px;margin-bottom:20px;display:flex}.filter-btn{border-radius:var(--radius-xl);background:var(--color-white);font-size:13px;font-family:var(--font-primary);cursor:pointer;color:var(--color-medium-gray);border:1px solid #e2e8f0;padding:8px 16px;transition:all .2s}.filter-btn:hover{border-color:var(--color-medium-gray)}.filter-btn.active{background-color:var(--color-dark-navy);color:var(--color-white);border-color:var(--color-dark-navy)}.flashcards-list{flex-direction:column;gap:12px;display:flex}.flashcard-item{background:var(--color-white);border-radius:var(--radius-md);box-shadow:var(--shadow-subtle);justify-content:space-between;align-items:center;padding:20px 24px;transition:box-shadow .2s;display:flex}.flashcard-item:hover{box-shadow:var(--shadow-medium)}.flashcard-item .flashcard-content{flex:1}.flashcard-item .flashcard-question{color:var(--color-dark-navy);margin-bottom:4px;font-size:16px;font-weight:500}.flashcard-item .flashcard-answer{color:var(--color-medium-gray);-webkit-line-clamp:2;-webkit-box-orient:vertical;font-size:14px;display:-webkit-box;overflow:hidden}.flashcard-item .flashcard-category-tag{border-radius:12px;margin-top:8px;padding:2px 10px;font-size:12px;font-weight:500;display:inline-block}.flashcard-item .flashcard-actions{gap:8px;margin-left:16px;display:flex}.modal-overlay{z-index:1000;-webkit-backdrop-filter:blur(4px);backdrop-filter:blur(4px);background:#00000080;justify-content:center;align-items:center;animation:.2s fadeIn;display:flex;position:fixed;inset:0}.modal{background:var(--color-white);border-radius:var(--radius-xl);width:90%;max-width:500px;max-height:90vh;padding:32px;animation:.3s slideUp;overflow-y:auto}.modal h2{color:var(--color-dark-navy);margin-bottom:24px;font-size:22px;font-weight:600}.modal-actions{justify-content:flex-end;gap:12px;margin-top:28px;display:flex}.btn-cancel{background:var(--color-white);font-size:14px;font-family:var(--font-primary);cursor:pointer;color:var(--color-medium-navy);border:1px solid #e2e8f0;border-radius:10px;padding:10px 24px;transition:background-color .2s}.btn-cancel:hover{background-color:var(--color-light-gray)}.btn-save{background-color:var(--color-blue);color:var(--color-white);font-size:14px;font-weight:500;font-family:var(--font-primary);cursor:pointer;border:none;border-radius:10px;padding:10px 24px;transition:background-color .2s}.btn-save:hover{background-color:var(--color-blue-hover)}.btn-danger{background-color:var(--color-danger)}.btn-danger:hover{background-color:var(--color-danger-hover)}.color-options{flex-wrap:wrap;gap:8px;display:flex}.color-option{cursor:pointer;border:3px solid #0000;border-radius:50%;width:36px;height:36px;transition:transform .2s,border-color .2s}.color-option:hover{transform:scale(1.1)}.color-option.selected{border-color:var(--color-dark-navy);transform:scale(1.15)}.modal textarea{resize:vertical;border-radius:var(--radius-md);min-height:100px;font-size:16px;font-family:var(--font-primary);color:var(--color-medium-navy);background:var(--color-white);border:2px solid #e2e8f0;outline:none;width:100%;padding:14px 16px;transition:border-color .2s,box-shadow .2s}.modal textarea::placeholder{color:var(--color-medium-gray)}.modal textarea:focus{border-color:var(--color-blue);box-shadow:0 0 0 3px #3b82f626}.study-container{max-width:900px;margin:0 auto;padding:32px}.study-header{text-align:center;margin-bottom:40px}.study-header h1{color:var(--color-dark-navy);margin-bottom:8px;font-size:28px;font-weight:700}.study-header p{color:var(--color-medium-gray);font-size:16px}.study-categories{grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:16px;margin-bottom:40px;display:grid}.study-category-card{background:var(--color-white);border-radius:var(--radius-lg);text-align:center;cursor:pointer;box-shadow:var(--shadow-subtle);border:2px solid #0000;padding:24px;transition:transform .2s,box-shadow .2s,border-color .2s}.study-category-card:hover{box-shadow:var(--shadow-medium);transform:translateY(-2px)}.study-category-card.selected{border-color:var(--color-blue)}.study-category-card h3{color:var(--color-dark-navy);margin-top:12px;font-size:16px;font-weight:600}.study-category-card .emoji{font-size:32px}.btn-start-study{background-color:var(--color-dark-navy);color:var(--color-white);border-radius:var(--radius-md);cursor:pointer;font-size:16px;font-weight:600;font-family:var(--font-primary);border:none;margin:0 auto;padding:14px 48px;transition:background-color .2s;display:block}.btn-start-study:hover{background-color:var(--color-light-navy)}.study-progress{text-align:center;margin-bottom:32px}.progress-bar-container{background-color:#e2e8f0;border-radius:4px;height:8px;margin-bottom:12px;overflow:hidden}.progress-bar-fill{background:linear-gradient(90deg, var(--color-blue), #8b5cf6);border-radius:4px;height:100%;transition:width .3s}.progress-text{color:var(--color-medium-gray);font-size:14px}.flip-card-container{perspective:1000px;max-width:600px;margin:0 auto 32px}.flip-card{cursor:pointer;width:100%;min-height:320px;transform-style:preserve-3d;transition:transform .6s;position:relative}.flip-card.flipped{transform:rotateY(180deg)}.flip-card-front,.flip-card-back{backface-visibility:hidden;border-radius:var(--radius-xl);text-align:center;flex-direction:column;justify-content:center;align-items:center;padding:48px 40px;display:flex;position:absolute;inset:0}.flip-card-front{background:var(--color-white);box-shadow:var(--shadow-medium)}.flip-card-back{background:var(--color-dark-navy);color:var(--color-white);transform:rotateY(180deg)}.flip-card-label{text-transform:uppercase;letter-spacing:2px;opacity:.5;margin-bottom:20px;font-size:12px;font-weight:600}.flip-card-text{font-size:20px;font-weight:500;line-height:1.6}.flip-hint{color:var(--color-medium-gray);margin-top:20px;font-size:13px}.study-nav{justify-content:center;align-items:center;gap:16px;display:flex}.btn-nav{background:var(--color-white);cursor:pointer;width:48px;height:48px;color:var(--color-medium-navy);border:1px solid #e2e8f0;border-radius:50%;justify-content:center;align-items:center;font-size:20px;transition:background-color .2s;display:flex}.btn-nav:hover{background-color:var(--color-light-gray)}.btn-nav:disabled{opacity:.3;cursor:not-allowed}.btn-shuffle{background:var(--color-white);font-size:14px;font-family:var(--font-primary);cursor:pointer;color:var(--color-medium-navy);border:1px solid #e2e8f0;border-radius:10px;padding:10px 24px;transition:background-color .2s}.btn-shuffle:hover{background-color:var(--color-light-gray)}.btn-back-study{color:var(--color-medium-gray);cursor:pointer;font-size:14px;font-family:var(--font-primary);background:0 0;border:1px solid #e2e8f0;border-radius:10px;margin-top:32px;margin-left:auto;margin-right:auto;padding:10px 24px;transition:color .2s,border-color .2s;display:block}.btn-back-study:hover{color:var(--color-dark-navy);border-color:var(--color-medium-gray)}.empty-state{text-align:center;color:var(--color-medium-gray);padding:60px 20px}.empty-state .empty-icon{margin-bottom:16px;font-size:48px}.empty-state p{font-size:16px}.pagination{justify-content:center;align-items:center;gap:16px;margin-top:24px;display:flex}.btn-page{background:var(--color-white);color:var(--color-medium-navy);font-size:14px;font-family:var(--font-primary);cursor:pointer;border:1px solid #e2e8f0;border-radius:8px;padding:8px 16px;font-weight:500;transition:all .2s}.btn-page:hover:not(:disabled){background:var(--color-light-gray);border-color:#cbd5e1}.btn-page:disabled{opacity:.5;cursor:not-allowed}.page-info{color:var(--color-medium-gray);font-size:14px;font-weight:500}.loading-container{justify-content:center;align-items:center;min-height:60vh;display:flex}.spinner{border:4px solid #e2e8f0;border-top-color:var(--color-blue);border-radius:50%;width:40px;height:40px;animation:.8s linear infinite spin}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}@keyframes slideUp{0%{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}@keyframes spin{0%{transform:rotate(0)}to{transform:rotate(360deg)}}@keyframes flipIn{0%{opacity:0;transform:scale(.95)}to{opacity:1;transform:scale(1)}}@media (width<=768px){.dashboard{padding:16px}.dashboard-header{flex-direction:column;align-items:flex-start;gap:12px}.auth-card{margin:20px;padding:32px 24px}.navbar{padding:0 16px}.navbar-links{gap:4px}.navbar-links .link-text,.navbar-brand .brand-text{display:none}.navbar-brand{font-size:24px}.flip-card-front,.flip-card-back{padding:32px 24px}.flip-card-text{font-size:18px}.categories-grid{grid-template-columns:1fr}.modal{margin:16px;padding:24px}}