:root{--studydog-primary: #2e5c4e;--studydog-accent: #e8a33d;--studydog-bg: #f7f5f0;--studydog-text: #24302b;--studydog-radius: 10px;--studydog-font: "Segoe UI", system-ui, sans-serif}*{box-sizing:border-box}body{margin:0;font-family:var(--studydog-font);background:var(--studydog-bg);color:var(--studydog-text)}.app-shell{max-width:960px;margin:0 auto;padding:24px}.brand-header{display:flex;align-items:center;justify-content:space-between;padding:16px 0;border-bottom:2px solid var(--studydog-primary);margin-bottom:24px}.brand-header h1{color:var(--studydog-primary);font-size:22px;margin:0}nav a{margin-left:16px;color:var(--studydog-primary);text-decoration:none;font-weight:600}.card{background:#fff;border-radius:var(--studydog-radius);padding:20px;box-shadow:0 1px 4px #00000014;margin-bottom:16px}button,.btn{background:var(--studydog-primary);color:#fff;border:none;border-radius:var(--studydog-radius);padding:10px 18px;font-weight:600;cursor:pointer}button.secondary{background:var(--studydog-accent)}button.danger{background:#b3452f}input,select,textarea{width:100%;padding:8px 10px;border:1px solid #ccc;border-radius:6px;margin-bottom:12px;font-family:inherit}.chat-window{height:320px;overflow-y:auto;border:1px solid #ddd;border-radius:var(--studydog-radius);padding:12px;background:#fff}.chat-message{margin-bottom:8px}.chat-message.mine{text-align:right}.chat-message .bubble{display:inline-block;padding:6px 12px;border-radius:14px;background:#eee}.chat-message.mine .bubble{background:var(--studydog-primary);color:#fff}