diff --git a/web/src/components/TargetDetail.tsx b/web/src/components/TargetDetail.tsx
new file mode 100644
index 0000000..6a1a637
--- /dev/null
+++ b/web/src/components/TargetDetail.tsx
@@ -0,0 +1,207 @@
+import { motion } from "motion/react";
+import type { Bucket, Incident, LiveTarget } from "../lib/types";
+import { StatusRing } from "./StatusRing";
+import { Sparkline } from "./Sparkline";
+import { RadialDay } from "./RadialDay";
+import { IncidentList } from "./IncidentList";
+import {
+  fmtDate,
+  fmtInterval,
+  fmtLatency,
+  fmtNumber,
+  fmtUptime,
+  pctSign,
+} from "../lib/format";
+import { springs, STATE_COLOR, useUI } from "../lib/ui";
+
+interface TargetDetailProps {
+  target: LiveTarget;
+  buckets: Bucket[];
+  incidents: Incident[];
+  onClose: () => void;
+}
+
+function Stat({ label, value, accent }: { label: string; value: string; accent?: string }) {
+  return (
+    <div className="flex flex-col gap-1 min-w-0">
+      <span className="microlabel">{label}</span>
+      <span
+        className="text-[13px] tabular truncate"
+        style={{ color: accent ?? "var(--color-paper)" }}
+        dir="ltr"
+      >
+        {value}
+      </span>
+    </div>
+  );
+}
+
+/**
+ * The expanded view: shares its layout with the grid card, so the ring
+ * physically travels from the grid into the panel.
+ */
+export function TargetDetail({ target, buckets, incidents, onClose }: TargetDetailProps) {
+  const { t, lang, window, reduced } = useUI();
+  const uptime = window === "7d" ? target.uptime_7d : target.uptime_24h;
+
+  return (
+    <motion.div
+      className="fixed inset-0 z-30 flex items-center justify-center p-4 sm:p-8"
+      initial={{ opacity: 0 }}
+      animate={{ opacity: 1 }}
+      exit={{ opacity: 0, transition: { duration: 0.18 } }}
+    >
+      {/* veil */}
+      <div
+        className="absolute inset-0 bg-ink-950/75 backdrop-blur-[6px]"
+        onClick={onClose}
+      />
+
+      <motion.div
+        layoutId={`card-${target.id}`}
+        transition={reduced ? { duration: 0 } : springs.layout}
+        className="relative w-full max-w-3xl max-h-[88vh] overflow-y-auto rounded-md border border-ink-700 bg-ink-900"
+        style={{ boxShadow: "var(--panel-shadow)" }}
+        role="dialog"
+        aria-modal="true"
+        aria-label={target.name}
+      >
+        {/* state edge */}
+        <span
+          aria-hidden
+          className="absolute inset-x-0 top-0 h-px"
+          style={{
+            background: `linear-gradient(to right, transparent, ${STATE_COLOR[target.state]}, transparent)`,
+          }}
+        />
+
+        <button
+          onClick={onClose}
+          aria-label={t.close}
+          className="absolute top-4 end-4 z-10 size-8 rounded-full border border-ink-700 text-paper-faint hover:text-paper hover:border-ink-700 hover:bg-ink-850 transition-colors cursor-pointer text-[13px]"
+        >
+          ✕
+        </button>
+
+        <div className="p-6 sm:p-8">
+          {/* top: ring + identity */}
+          <div className="flex flex-col sm:flex-row items-center sm:items-start gap-6">
+            <motion.div
+              layoutId={`ring-${target.id}`}
+              transition={reduced ? { duration: 0 } : springs.layout}
+              className="shrink-0"
+            >
+              <StatusRing target={target} uptime={uptime} size={185} />
+            </motion.div>
+
+            <div className="flex-1 min-w-0 text-center sm:text-start pt-2">
+              <motion.h2
+                className="text-[34px] leading-tight text-paper"
+                style={{ fontFamily: "var(--font-display)" }}
+                initial={reduced ? false : { opacity: 0, y: 8 }}
+                animate={{ opacity: 1, y: 0 }}
+                transition={{ delay: 0.12 }}
+              >
+                {target.name}
+              </motion.h2>
+              <p className="mt-1 text-[11px] text-paper-faint tabular font-mono" dir="ltr">
+                {target.type === "http" ? (
+                  <a
+                    href={target.endpoint}
+                    target="_blank"
+                    rel="noreferrer"
+                    className="hover:text-brass transition-colors"
+                    title={t.openEndpoint}
+                  >
+                    {target.endpoint} ↗
+                  </a>
+                ) : (
+                  target.endpoint
+                )}
+              </p>
+              <p className="mt-2 text-[12px]" style={{ color: STATE_COLOR[target.state] }}>
+                ● {t.state[target.state]}
+                {target.fails > 0 && target.state !== "down" && (
+                  <span className="text-paper-faint"> · {fmtNumber(lang, target.fails)} {t.failed}</span>
+                )}
+              </p>
+
+              <motion.div
+                className="mt-5 grid grid-cols-2 sm:grid-cols-3 gap-x-6 gap-y-4"
+                initial={reduced ? false : { opacity: 0 }}
+                animate={{ opacity: 1 }}
+                transition={{ delay: 0.2 }}
+              >
+                <Stat label={t.latency + " p50"} value={fmtLatency(lang, target.latency.p50_ms)} />
+                <Stat label={t.latency + " p95"} value={fmtLatency(lang, target.latency.p95_ms)} />
+                <Stat
+                  label={t.lastCheck}
+                  value={target.last ? fmtDate(lang, target.last.ts) : "—"}
+                />
+                <Stat label={t.interval} value={fmtInterval(lang, target.interval_sec)} />
+                {target.uptime_30d !== undefined ? (
+                  <Stat
+                    label={t.uptime30}
+                    value={`${fmtUptime(lang, target.uptime_30d)}${pctSign(lang)}`}
+                  />
+                ) : (
+                  <Stat label="type" value={target.type.toUpperCase()} />
+                )}
+                {target.cert_days !== undefined && (
+                  <Stat
+                    label={t.certExpiry}
+                    value={`${fmtNumber(lang, target.cert_days)}${t.daysShort}`}
+                    accent={
+                      target.cert_days < 14
+                        ? "var(--color-warn)"
+                        : "var(--color-paper)"
+                    }
+                  />
+                )}
+              </motion.div>
+            </div>
+          </div>
+
+          {/* middle: sparkline + personal day dial */}
+          <motion.div
+            className="mt-8 grid gap-8 sm:grid-cols-[1fr_auto] items-start"
+            initial={reduced ? false : { opacity: 0, y: 10 }}
+            animate={{ opacity: 1, y: 0 }}
+            transition={{ delay: 0.26, ...springs.gentle }}
+          >
+            <div>
+              <div className="microlabel mb-3 flex items-baseline gap-4">
+                <span>{t.latency}</span>
+                <span className="rule-fade flex-1" />
+              </div>
+              <Sparkline series={target.series} pulse={target.pulse} />
+            </div>
+            <div className="hidden sm:block">
+              <RadialDay
+                targets={[target]}
+                dayBuckets={{ [target.id]: buckets }}
+                only={target.id}
+                size={185}
+                caption={false}
+              />
+            </div>
+          </motion.div>
+
+          {/* bottom: incidents */}
+          <motion.div
+            className="mt-8"
+            initial={reduced ? false : { opacity: 0, y: 10 }}
+            animate={{ opacity: 1, y: 0 }}
+            transition={{ delay: 0.32, ...springs.gentle }}
+          >
+            <div className="microlabel mb-3 flex items-baseline gap-4">
+              <span>{t.recentIncidents}</span>
+              <span className="rule-fade flex-1" />
+            </div>
+            <IncidentList incidents={incidents.slice(0, 6)} targets={[target]} hideTarget />
+          </motion.div>
+        </div>
+      </motion.div>
+    </motion.div>
+  );
+}