:root{--bg-primary: #faf9f7;--bg-card: #ffffff;--text-primary: #2d3748;--text-secondary: #718096;--accent: #6b8e8c;--accent-hover: #5a7a78;--success: #68a67d;--error: #c97b7b;--border: #e2e0dc;--shadow: 0 2px 8px rgba(0, 0, 0, .06);--shadow-lg: 0 4px 16px rgba(0, 0, 0, .08);--radius: 12px;--radius-sm: 8px}*{margin:0;padding:0;box-sizing:border-box}body{font-family:Inter,-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;background-color:var(--bg-primary);color:var(--text-primary);line-height:1.6;min-height:100vh}button{font-family:inherit;cursor:pointer;border:none;transition:all .2s ease}input,textarea{font-family:inherit;border:1px solid var(--border);border-radius:var(--radius-sm);padding:12px 16px;font-size:1rem;background:var(--bg-card);color:var(--text-primary);transition:border-color .2s ease}input:focus,textarea:focus{outline:none;border-color:var(--accent)}input::placeholder,textarea::placeholder{color:var(--text-secondary)}.container{max-width:600px;margin:0 auto;padding:24px}.card{background:var(--bg-card);border-radius:var(--radius);box-shadow:var(--shadow);padding:24px}.btn{display:inline-flex;align-items:center;justify-content:center;padding:12px 24px;border-radius:var(--radius-sm);font-weight:500;font-size:1rem;gap:8px}.btn-primary{background:var(--accent);color:#fff}.btn-primary:hover{background:var(--accent-hover)}.btn-secondary{background:transparent;border:1px solid var(--border);color:var(--text-primary)}.btn-secondary:hover{background:var(--bg-primary)}.btn-success{background:var(--success);color:#fff}.btn-success:hover{opacity:.9}.btn-error{background:var(--error);color:#fff}.btn-error:hover{opacity:.9}.btn-ghost{background:transparent;color:var(--text-secondary);padding:8px 12px}.btn-ghost:hover{color:var(--text-primary);background:#0000000a}.btn-block{width:100%}h1,h2,h3{font-weight:600;line-height:1.3}.text-secondary{color:var(--text-secondary)}.text-center{text-align:center}.mb-1{margin-bottom:8px}.mb-2{margin-bottom:16px}.mb-3{margin-bottom:24px}.mb-4{margin-bottom:32px}.mt-1{margin-top:8px}.mt-2{margin-top:16px}.mt-3{margin-top:24px}.mt-4{margin-top:32px}.flex{display:flex}.flex-col{flex-direction:column}.items-center{align-items:center}.justify-center{justify-content:center}.justify-between{justify-content:space-between}.gap-1{gap:8px}.gap-2{gap:16px}.gap-3{gap:24px}.app-header{text-align:center;padding:16px;font-size:.875rem;color:var(--text-secondary);font-weight:500;letter-spacing:.5px}.spinner{width:24px;height:24px;border:2px solid var(--border);border-top-color:var(--accent);border-radius:50%;animation:spin .8s linear infinite}.spinner-lg{width:48px;height:48px;border:3px solid var(--border);border-top-color:var(--accent);border-radius:50%;animation:spin .8s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}@keyframes pulse-text{0%,to{opacity:1}50%{opacity:.6}}.loading-text{animation:pulse-text 2s ease-in-out infinite}.fade-in{animation:fadeIn .3s ease}@keyframes fadeIn{0%{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}.flip-card{perspective:1000px;width:100%;height:420px;overflow:hidden}.flip-card-inner{position:relative;width:100%;height:100%;transition:transform .5s ease;transform-style:preserve-3d}.flip-card.flipped .flip-card-inner{transform:rotateY(180deg)}.flip-card.swipe-left .flip-card-inner{animation:swipeOutLeft .3s ease forwards}.flip-card.swipe-right .flip-card-inner{animation:swipeOutRight .3s ease forwards}.flip-card.swipe-in-left .flip-card-inner{animation:swipeInFromRight .3s ease forwards}.flip-card.swipe-in-right .flip-card-inner{animation:swipeInFromLeft .3s ease forwards}@keyframes swipeOutLeft{0%{transform:translate(0);opacity:1}to{transform:translate(-100%);opacity:0}}@keyframes swipeOutRight{0%{transform:translate(0);opacity:1}to{transform:translate(100%);opacity:0}}@keyframes swipeInFromRight{0%{transform:translate(100%);opacity:0}to{transform:translate(0);opacity:1}}@keyframes swipeInFromLeft{0%{transform:translate(-100%);opacity:0}to{transform:translate(0);opacity:1}}.flip-card-front,.flip-card-back{position:absolute;width:100%;height:100%;backface-visibility:hidden;border-radius:var(--radius);box-shadow:var(--shadow-lg);display:flex;flex-direction:column;justify-content:center;align-items:center;padding:32px;text-align:center}.flip-card-front{background:var(--bg-card)}.flip-card-back{background:linear-gradient(135deg,var(--accent) 0%,var(--accent-hover) 100%);color:#fff;transform:rotateY(180deg)}.flip-card-label{position:absolute;top:16px;left:0;right:0;font-size:.7rem;text-transform:uppercase;letter-spacing:1px;opacity:.6;display:flex;align-items:center;justify-content:center}.flip-card-back .flip-card-label{opacity:.8}.flip-card-content{font-size:1.15rem;line-height:1.5;max-height:280px;overflow-y:auto}.flip-card-hint{position:absolute;bottom:16px;font-size:.75rem;opacity:.5}.flip-card-color-toggle{position:absolute;bottom:12px;right:16px;background:#fff3;border:none;color:#fff;padding:6px 12px;border-radius:16px;font-size:.75rem;cursor:pointer;transition:background .2s}.flip-card-color-toggle:hover{background:#ffffff4d}.color-box{background:var(--bg-card);border-left:3px solid var(--accent);border-radius:var(--radius-sm);padding:16px 20px;margin-top:16px;font-size:.9rem;line-height:1.6;color:var(--text-secondary);box-shadow:var(--shadow)}.study-options{margin-top:20px;padding-top:16px;border-top:1px solid var(--border)}.study-options-label{font-size:.7rem;text-transform:uppercase;letter-spacing:.5px;color:var(--text-secondary);opacity:.6;margin-bottom:8px}.study-options-list{display:flex;flex-direction:column;gap:4px}.study-option{font-size:.85rem;color:var(--text-secondary);font-style:italic;opacity:.7;padding:2px 0}.edit-icon-btn{background:none;border:none;padding:4px;margin-left:8px;cursor:pointer;opacity:.4;transition:opacity .2s;vertical-align:middle}.edit-icon-btn:hover{opacity:.8}.flip-card-back .edit-icon-btn{color:#fff}.flip-card-front .edit-icon-btn{color:var(--text-secondary)}.edit-field{width:100%;max-width:300px}.edit-field textarea{width:100%;border:1px solid var(--border);border-radius:var(--radius-sm);padding:8px 12px;font-size:.9rem;resize:none;background:#fff;color:var(--text-primary)}.flip-card-back .edit-field textarea{background:#fffffff2}.edit-actions{display:flex;gap:8px;margin-top:8px;justify-content:center}.edit-btn{padding:6px 12px;border:none;border-radius:var(--radius-sm);cursor:pointer;display:flex;align-items:center;gap:4px}.edit-btn.save{background:var(--success);color:#fff}.edit-btn.cancel{background:#0000001a;color:var(--text-secondary)}.flip-card-back .edit-btn.cancel{background:#fff3;color:#fff}.modal-overlay{position:fixed;top:0;left:0;right:0;bottom:0;background:#00000080;display:flex;align-items:center;justify-content:center;z-index:1000;padding:24px}.modal{max-width:400px;width:100%;animation:fadeIn .2s ease}