:root{--bg-start: #eef2ff;--bg-mid: #ffffff;--bg-end: #faf5ff;--surface: rgba(255, 255, 255, .8);--surface-strong: #ffffff;--border-soft: #f3f4f6;--border-input: #e5e7eb;--text: #1f2937;--text-muted: #6b7280;--text-faint: #9ca3af;--accent: #6366f1;--accent-strong: #4f46e5;--accent-soft: #e0e7ff;--accent-secondary: #a855f7;--status-ok: #4ade80;--shadow-card: 0 8px 30px rgba(0, 0, 0, .04);--shadow-button: 0 10px 24px rgba(99, 102, 241, .25)}*{box-sizing:border-box}html,body{height:100%}body{margin:0;font-family:Inter,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica,Arial,sans-serif;color:var(--text);background:linear-gradient(135deg,var(--bg-start),var(--bg-mid),var(--bg-end));min-height:100%}.page{min-height:100vh;display:flex;align-items:center;justify-content:center;padding:1rem}.chat-shell{width:100%;max-width:42rem;height:85vh;display:flex;flex-direction:column;background:var(--surface);backdrop-filter:blur(20px);-webkit-backdrop-filter:blur(20px);border-radius:1.5rem;border:1px solid rgba(255,255,255,.5);box-shadow:var(--shadow-card);overflow:hidden}.chat-header{display:flex;align-items:center;justify-content:space-between;padding:1.25rem 2rem;background:#ffffff80;border-bottom:1px solid var(--border-soft)}.chat-title{font-size:1.125rem;font-weight:600;letter-spacing:-.01em;margin:0}.chat-subtitle{font-size:.85rem;color:var(--accent);font-weight:500;margin:.15rem 0 0;display:inline-flex;align-items:center;gap:.35rem;flex-wrap:wrap}.user-badge{display:inline-flex;align-items:center;gap:.25rem;color:var(--text-muted)}.icon-button{display:inline-flex;align-items:center;justify-content:center;padding:2px;margin-left:2px;background:transparent;border:none;border-radius:4px;color:var(--text-muted);cursor:pointer;opacity:.7;transition:opacity .15s ease,color .15s ease,background .15s ease}.icon-button:hover{opacity:1;color:var(--accent);background:#0000000a}.icon-button:focus-visible{outline:2px solid var(--accent);outline-offset:1px}.status-dot{width:.75rem;height:.75rem;border-radius:50%;background:var(--status-ok);animation:pulse-glow 2s cubic-bezier(.4,0,.6,1) infinite}.chat-messages{flex:1;overflow-y:auto;padding:2rem;display:flex;flex-direction:column;gap:1.25rem;scroll-behavior:smooth}.chat-messages::-webkit-scrollbar{width:6px}.chat-messages::-webkit-scrollbar-track{background:transparent}.chat-messages::-webkit-scrollbar-thumb{background:#9ca3af80;border-radius:10px}.message-row{display:flex}.message-row.is-user{justify-content:flex-end}.message-row.is-tutor{justify-content:flex-start}.message-bubble{max-width:80%;padding:.9rem 1.25rem;border-radius:1rem;line-height:1.5;white-space:pre-wrap;word-wrap:break-word;box-shadow:0 1px 2px #0000000a;animation:slide-up .35s ease-out}.message-bubble.is-user{background:linear-gradient(135deg,var(--accent),var(--accent-secondary));color:#fff;border-bottom-right-radius:.25rem}.message-bubble.is-tutor{background:var(--surface-strong);color:var(--text);border:1px solid var(--border-soft);border-bottom-left-radius:.25rem}.typing{display:inline-flex;align-items:center;gap:.4rem;padding:.9rem 1.25rem;background:var(--surface-strong);border:1px solid var(--border-soft);border-radius:1rem 1rem 1rem .25rem;animation:fade-in .25s ease-out}.typing-dot{width:.5rem;height:.5rem;border-radius:50%;background:var(--accent);animation:dot-bounce 1s infinite}.typing-dot:nth-child(2){animation-delay:.15s}.typing-dot:nth-child(3){animation-delay:.3s}.chat-footer{padding:1.25rem 1.5rem;background:#ffffff80;border-top:1px solid var(--border-soft)}.input-form{position:relative;display:flex;align-items:flex-end}.input-field{flex:1;padding:.85rem 3.5rem .85rem 1.5rem;font:inherit;line-height:1.4;color:var(--text);background:#f9fafbb3;border:1px solid var(--border-input);border-radius:1.4rem;outline:none;transition:border-color .15s ease,box-shadow .15s ease;resize:none;overflow-y:auto;max-height:12rem;min-height:2.8rem;font-family:inherit}.input-field::placeholder{color:var(--text-faint)}.input-field:focus{border-color:#c7d2fe;box-shadow:0 0 0 4px var(--accent-soft)}.input-field:disabled{opacity:.6;cursor:not-allowed}.send-button{position:absolute;bottom:.4rem;right:.4rem;display:inline-flex;align-items:center;justify-content:center;width:2.6rem;height:2.6rem;border:none;border-radius:50%;background:var(--accent);color:#fff;cursor:pointer;transition:background .15s ease,box-shadow .15s ease,transform .05s ease}.send-button:hover:not(:disabled){background:var(--accent-strong);box-shadow:var(--shadow-button)}.send-button:active:not(:disabled){transform:scale(.97)}.send-button:disabled{opacity:.4;cursor:not-allowed}.send-button svg{width:1.1rem;height:1.1rem;margin-left:.15rem}.completion{display:flex;align-items:center;justify-content:space-between;gap:1rem}.completion-text{margin:0;font-size:.9rem;color:var(--text-muted)}.completion-text strong{color:var(--text);font-weight:600}.next-button{padding:.65rem 1.25rem;border:none;border-radius:999px;background:var(--accent);color:#fff;font:inherit;font-size:.9rem;font-weight:500;cursor:pointer;transition:background .15s ease,box-shadow .15s ease}.next-button:hover{background:var(--accent-strong);box-shadow:var(--shadow-button)}@keyframes fade-in{0%{opacity:0}to{opacity:1}}@keyframes slide-up{0%{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}@keyframes pulse-glow{0%,to{opacity:1;box-shadow:0 0 12px #4ade8080}50%{opacity:.8;box-shadow:0 0 18px #4ade80cc}}@keyframes dot-bounce{0%,60%,to{transform:translateY(0);opacity:.4}30%{transform:translateY(-4px);opacity:1}}