Add shareable daily check-in card

app/globals.css

@@ -174,10 +174,11 @@ h1{letter-spacing:-.04em;font-size:clamp(2rem,4vw,2.85rem)}
 .task-toolbar{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-bottom:13px;color:#64748b;font-size:.84rem}.today-button{border:1px solid #bfd3fb;background:#f7faff;color:#1d4ed8;border-radius:999px;padding:7px 11px;font:inherit;font-weight:700;cursor:pointer;transition:.16s background,.16s transform}.today-button:hover{background:#e7f0ff;transform:translateY(-1px)}
 .task:hover{transform:translateX(2px);border-color:#94bafc}.task.done{background:#f2f7ff}
 .task b{background:#e7efff;color:#315fd5}.task.done b{background:#cfe0ff}
+.completion-card{display:flex;align-items:center;justify-content:space-between;gap:22px;margin-top:18px;padding:19px 20px;border:1px solid #bad3ff;border-radius:18px;background:linear-gradient(125deg,#edf5ff,#fff)}.completion-card h3{margin:4px 0 7px;font-size:1.12rem;letter-spacing:-.02em}.completion-card>div>p:last-child{margin:0;color:#64748b;font-size:.88rem;line-height:1.55}.share-card-button{display:inline-flex;align-items:center;justify-content:center;gap:8px;flex:none;border:0;border-radius:12px;background:#2563eb;color:#fff;padding:12px 15px;font:inherit;font-weight:700;cursor:pointer;box-shadow:0 9px 18px #bfdbfe;transition:.16s transform,.16s background}.share-card-button:hover{background:#1d4ed8;transform:translateY(-1px)}
 .review{margin-top:26px}.review textarea{background:#fbfdff;border-color:#d5e0f0}.pill{transition:.15s transform}.pill:hover:not(:disabled){transform:translateY(-1px)}
 aside{display:grid;gap:14px}.side-calendar{margin:0;padding:18px;border-radius:22px;border-color:#d9e6ff;box-shadow:0 16px 36px #bfd5fb77}.calendar-head{gap:10px}.calendar-head h2{font-size:1.22rem;letter-spacing:-.02em}.month-tabs{gap:3px}.month-tabs button{padding:6px 8px;font-size:.76rem;min-width:36px}.weekdays{margin:16px 0 7px;font-size:.7rem;gap:4px}.calendar-grid{gap:4px}.calendar-day{min-height:47px;padding:5px 4px;border-radius:10px;font-size:.8rem}.calendar-day small{font-size:.56rem;line-height:1.1}.calendar-day.chosen{outline-width:2px}.calendar-note{font-size:.7rem;line-height:1.9}.calendar-note i{width:7px;height:7px;margin:0 3px 0 8px}.dark,.side{margin:0;border-radius:20px}.dark{padding:22px;background:linear-gradient(145deg,#102555,#1d4ed8)}.dark h2{font-size:1.45rem;letter-spacing:-.025em}.side{padding:18px;border-color:#d9e6ff;box-shadow:0 10px 25px #dbeafe66}.side p{margin:12px 0;font-size:.8rem}
 @media(max-width:980px){.layout{grid-template-columns:minmax(0,1fr) 300px}.calendar-day{min-height:43px}.calendar-day small{font-size:.51rem}.month-tabs button{padding:5px 6px;min-width:31px}}
-@media(max-width:760px){.shell{padding:26px 15px 42px}.layout{grid-template-columns:1fr}.side-calendar{order:-1}.calendar-day{min-height:55px;padding:6px}.calendar-day small{font-size:.6rem}.month-tabs button{padding:6px 10px;min-width:38px}}
+@media(max-width:760px){.shell{padding:26px 15px 42px}.layout{grid-template-columns:1fr}.side-calendar{order:-1}.calendar-day{min-height:55px;padding:6px}.calendar-day small{font-size:.6rem}.month-tabs button{padding:6px 10px;min-width:38px}.smart-tip,.completion-card{grid-template-columns:1fr;align-items:flex-start}.completion-card{flex-direction:column}.share-card-button{width:100%}}
 @media(max-width:420px){.task-toolbar{align-items:flex-start;flex-direction:column}.today-button{width:100%}}
 
 .study-hub{max-width:1160px}.hub-grid{display:grid;grid-template-columns:.9fr 1.1fr;gap:20px;margin-top:22px}.hub-grid.lower{grid-template-columns:1fr 1fr}.hub-card{background:#fff;border:1px solid #d9e6ff;border-radius:22px;padding:24px;box-shadow:0 14px 34px #bfd5fb66}.hub-card h2{margin:5px 0 18px;font-size:1.42rem;letter-spacing:-.025em}.hub-card>p:not(.eyebrow){color:#64748b;line-height:1.65}.plan-card{background:linear-gradient(145deg,#122a61,#2865d9);color:#fff}.plan-card .eyebrow{color:#c9dcff}.plan-card strong{display:block;font-size:3.1rem;line-height:1;margin:18px 0 8px}.plan-card p,.plan-card small{color:#dceaff}.hub-card label{display:grid;gap:8px;margin:13px 0;color:#334155;font-size:.88rem;font-weight:700}.hub-card input,.hub-card textarea{width:100%;box-sizing:border-box;border:1px solid #d5e0f0;background:#fbfdff;border-radius:11px;padding:10px 11px;font:inherit;color:#172554}.hub-card textarea{min-height:88px;resize:vertical}.date-field{max-width:190px}.duration-grid{display:grid;grid-template-columns:repeat(5,1fr);gap:9px}.duration-grid label{font-size:.76rem}.duration-grid input{min-width:0;padding:9px}.score-grid{grid-template-columns:repeat(4,1fr)}.primary-action{display:inline-flex;align-items:center;gap:8px;border:0;border-radius:11px;background:#2563eb;color:#fff;padding:11px 15px;margin-top:8px;font:inherit;font-weight:700;cursor:pointer;box-shadow:0 8px 18px #bfdbfe}.primary-action:hover{background:#1d4ed8}.score-total{float:right;color:#2563eb;font-size:1.85rem}.mock-history{border-top:1px solid #e6edf9;margin-top:19px;padding-top:8px}.mock-history p{display:flex;justify-content:space-between;color:#64748b;font-size:.84rem;margin:10px 0}.mock-history b{color:#334155}