:root {
  --bg: #fafafa;
  --surface: #ffffff;
  --surface-2: #f8f9fa;
  --button-bg: #f1f3f4;
  --button-hover: #e8eaed;
  --fg: #202124;
  --muted: #5f6368;
  --accent: #ff3a6e;
  --accent-soft: #ffe4ec;
  --accent-hover: #ffd0dd;
  --primary: #1a73e8;
  --primary-soft: #e8f0fe;
  --primary-hover: #1557b0;
  --bad: #d93025;
  --bad-soft: #fce8e6;
  --warn: #f9ab00;
  --warn-soft: #fef7e0;
  --good: #188038;
  --border: #e8eaed;
  --shadow-sm: 0 1px 2px rgba(60, 64, 67, 0.08);
  --shadow-md: 0 1px 3px rgba(60, 64, 67, 0.08), 0 4px 12px rgba(60, 64, 67, 0.06);
  --shadow-lg: 0 10px 40px rgba(60, 64, 67, 0.12);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: "Google Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }


.shell {
  max-width: 720px;
  margin: 0 auto;
  padding: 24px 20px 80px;
}

.brand {
  margin-bottom: 24px;
}

.brand .label {
  display: block;
  font-size: 11px;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--muted);
  font-weight: 500;
  margin-bottom: 4px;
}

.brand h1 {
  font-size: 28px;
  font-weight: 600;
  letter-spacing: -0.4px;
  margin: 0;
}

.subtitle {
  color: var(--muted);
  margin: 0 0 20px;
  font-size: 13px;
  line-height: 1.6;
}

.calc {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 24px;
  box-shadow: var(--shadow-md);
}

.display {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 22px 24px;
  font-size: 32px;
  text-align: right;
  min-height: 80px;
  word-break: break-all;
  font-feature-settings: "tnum";
  color: var(--fg);
}

.display .small {
  display: block;
  color: var(--muted);
  font-size: 13px;
  margin-bottom: 6px;
  text-align: right;
  font-weight: 400;
}

.row {
  display: flex;
  gap: 10px;
  margin-top: 12px;
  flex-wrap: wrap;
}

button.btn {
  background: var(--button-bg);
  color: var(--fg);
  border: none;
  border-radius: 999px;
  padding: 16px 20px;
  font-size: 16px;
  font-weight: 500;
  font-family: inherit;
  cursor: pointer;
  flex: 1;
  min-width: 56px;
  transition: background 0.12s, transform 0.06s, box-shadow 0.12s;
  letter-spacing: 0.2px;
}
button.btn:hover { background: var(--button-hover); }
button.btn:active { transform: scale(0.97); }

button.btn.op {
  background: var(--accent-soft);
  color: var(--accent);
  font-weight: 600;
}
button.btn.op:hover { background: var(--accent-hover); }

button.btn.eq {
  background: var(--primary);
  color: #fff;
  font-weight: 600;
  box-shadow: 0 2px 8px rgba(26, 115, 232, 0.3);
}
button.btn.eq:hover { background: var(--primary-hover); }

button.btn.clear {
  background: var(--bad-soft);
  color: var(--bad);
  font-weight: 600;
}
button.btn.clear:hover { background: #fbd5d2; }

.hint {
  margin-top: 20px;
  padding: 14px 18px;
  background: var(--warn-soft);
  border-left: 3px solid var(--warn);
  color: #5f4c00;
  font-size: 13px;
  border-radius: 8px;
  line-height: 1.55;
}

input[type="range"] {
  width: 100%;
  height: 6px;
  appearance: none;
  background: var(--button-bg);
  border-radius: 999px;
  outline: none;
}
input[type="range"]::-webkit-slider-thumb {
  appearance: none;
  width: 20px;
  height: 20px;
  background: var(--accent);
  border-radius: 50%;
  cursor: pointer;
  box-shadow: 0 2px 6px rgba(255, 58, 110, 0.4);
  border: 2px solid #fff;
}
input[type="range"]::-moz-range-thumb {
  width: 20px;
  height: 20px;
  background: var(--accent);
  border-radius: 50%;
  cursor: pointer;
  box-shadow: 0 2px 6px rgba(255, 58, 110, 0.4);
  border: 2px solid #fff;
}

.slider-row {
  margin-top: 18px;
}
.slider-row label {
  display: flex;
  justify-content: space-between;
  font-size: 13px;
  color: var(--muted);
  margin-bottom: 8px;
  font-weight: 500;
}
.slider-row .val { color: var(--accent); font-weight: 600; }

.modal-bg {
  position: fixed;
  inset: 0;
  background: rgba(32, 33, 36, 0.45);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 100;
  backdrop-filter: blur(2px);
}
.modal-bg.open { display: flex; }
.modal {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 28px;
  max-width: 380px;
  width: 90%;
  text-align: center;
  box-shadow: var(--shadow-lg);
}
.modal h3 { margin-top: 0; color: var(--fg); }
.modal p { color: var(--muted); }
.modal .modal-actions { display: flex; gap: 10px; margin-top: 20px; }

.drunk-grid {
  position: relative;
  height: 380px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 16px;
  margin-top: 14px;
  overflow: hidden;
}
.drunk-btn {
  position: absolute;
  width: 64px;
  height: 64px;
  background: var(--button-bg);
  color: var(--fg);
  border: none;
  border-radius: 999px;
  font-size: 18px;
  font-weight: 500;
  cursor: pointer;
  font-family: inherit;
  box-shadow: var(--shadow-sm);
  transition: left 0.18s ease, top 0.18s ease, transform 0.1s, box-shadow 0.15s;
}
.drunk-btn:hover { box-shadow: var(--shadow-md); }
.drunk-btn.op { background: var(--accent-soft); color: var(--accent); font-weight: 600; }
.drunk-btn.eq { background: var(--primary); color: #fff; font-weight: 600; }
.drunk-btn.clear { background: var(--bad-soft); color: var(--bad); font-weight: 600; }

.riddle-q {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 18px;
  margin-top: 14px;
  text-align: center;
  font-size: 18px;
  color: var(--fg);
}
.riddle-input {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--fg);
  border-radius: 12px;
  padding: 14px;
  font-family: inherit;
  font-size: 18px;
  width: 100%;
  text-align: center;
  margin-top: 12px;
  transition: border-color 0.15s, box-shadow 0.15s;
}
.riddle-input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}
.error-msg {
  color: var(--bad);
  font-size: 13px;
  margin-top: 8px;
  text-align: center;
  min-height: 18px;
  font-weight: 500;
}

.spinner {
  display: inline-block;
  width: 14px;
  height: 14px;
  border: 2px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
  vertical-align: middle;
  margin-right: 6px;
}
@keyframes spin { to { transform: rotate(360deg); } }