/* =====================
   Theme Variables
===================== */
:root {
  --bg: #0b1220;
  --bg-accent: #1a2b5a;
  --card: rgba(16, 26, 51, 0.55);
  --card-strong: rgba(16, 26, 51, 0.45);
  --text: #e8eefc;
  --muted: #a8b3d6;
  --border: rgba(255, 255, 255, 0.12);
  --shadow: 0 12px 30px rgba(0, 0, 0, 0.35);

  --btn-bg: rgba(255, 255, 255, 0.06);
  --btn-bg-hover: rgba(255, 255, 255, 0.1);
  --btn-border: rgba(255, 255, 255, 0.18);

  --primary-bg1: rgba(71, 155, 255, 0.35);
  --primary-bg2: rgba(71, 155, 255, 0.12);
  --primary-border: rgba(71, 155, 255, 0.45);

  --ball-size: clamp(38px, 10.5vw, 52px);
  --ball-font: clamp(14px, 4.2vw, 17px);
}

/* Light Mode */
html[data-theme="light"] {
  --bg: #f6f7fb;
  --bg-accent: #e7ecff;
  --card: rgba(255, 255, 255, 0.85);
  --card-strong: rgba(255, 255, 255, 0.9);
  --text: #0f172a;
  --muted: #475569;
  --border: rgba(15, 23, 42, 0.12);

  --btn-bg: rgba(15, 23, 42, 0.04);
  --btn-bg-hover: rgba(15, 23, 42, 0.08);
  --btn-border: rgba(15, 23, 42, 0.14);

  --primary-bg1: rgba(37, 99, 235, 0.18);
  --primary-bg2: rgba(37, 99, 235, 0.08);
  --primary-border: rgba(37, 99, 235, 0.28);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family:
    system-ui,
    -apple-system,
    Segoe UI,
    Roboto,
    "Noto Sans KR",
    Arial,
    sans-serif;
  background: radial-gradient(
    1200px 800px at 20% 10%,
    var(--bg-accent) 0%,
    var(--bg) 55%
  );
  color: var(--text);
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 16px;
}

.wrap {
  width: min(840px, 100%);
  border-radius: 18px;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  overflow: hidden;
}

/* Header */
header {
  padding: 16px;
  display: flex;
  justify-content: space-between;
  gap: 12px;
  background: var(--card-strong);
  border-bottom: 1px solid var(--border);
}

.title-area h1 {
  margin: 0 0 6px;
  font-size: 20px;
}

.title-area p {
  margin: 0;
  font-size: 13px;
  color: var(--muted);
}

.theme-toggle {
  white-space: nowrap;
}

/* Main */
main {
  padding: 16px;
}

.result {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 12px;
  min-height: 150px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  justify-content: center;
}

.row {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  justify-content: center;
}

.ball {
  width: var(--ball-size);
  height: var(--ball-size);
  border-radius: 999px;
  display: grid;
  place-items: center;
  font-size: var(--ball-font);
  font-weight: 800;
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
}

.hint {
  text-align: center;
  color: var(--muted);
}

/* Buttons */
.controls {
  margin-top: 12px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.controls .primary {
  grid-column: 1 / -1;
}

button {
  min-height: 44px;
  border-radius: 12px;
  border: 1px solid var(--btn-border);
  background: var(--btn-bg);
  color: var(--text);
  font-weight: 700;
}

button.primary {
  background: linear-gradient(180deg, var(--primary-bg1), var(--primary-bg2));
  border-color: var(--primary-border);
}

/* Meta & History */
.meta {
  margin-top: 12px;
  font-size: 12px;
  color: var(--muted);
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.history {
  margin-top: 16px;
}

.history-list {
  list-style: none;
  padding: 0;
  display: grid;
  gap: 8px;
}

.history-item {
  padding: 10px;
  border-radius: 12px;
  background: var(--card);
  border: 1px solid var(--border);
  font-size: 13px;
}

/* Footer */
footer {
  padding: 14px;
  font-size: 12px;
  text-align: center;
  background: var(--card-strong);
  color: var(--muted);
}