:root {
  --bg: #0f172a; /* slate-900 */
  --bg-accent: #111827; /* gray-900 */
  --card: #0b1220cc; /* translucent card */
  --muted: #94a3b8; /* slate-400 */
  --text: #e5e7eb; /* gray-200 */
  --primary: #60a5fa; /* blue-400 */
  --primary-600: #2563eb; /* blue-600 */
  --danger: #ef4444; /* red-500 */
  --ring: #93c5fd; /* sky-300 */
  --success: #34d399; /* emerald-400 */
  --radius: 16px;
  --shadow: 0 10px 30px rgba(2, 6, 23, 0.45);
  --inner-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.06);
  --row-h: 56px; /* uniform row height */
}

/* Light mode (optional) */
@media (prefers-color-scheme: light) {
  :root {
    --bg: #f3f4f6; /* gray-100 */
    --bg-accent: #e5e7eb; /* gray-200 */
    --card: #ffffffee;
    --text: #0f172a; /* slate-900 */
    --muted: #64748b; /* slate-500 */
    --shadow: 0 12px 30px rgba(15, 23, 42, 0.12);
  }
}

* {
  box-sizing: border-box;
}
html,
body {
  height: 100%;
}
body {
  margin: 0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto,
    Helvetica, Arial, "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  color: var(--text);
  background: radial-gradient(
      1200px 800px at 10% 10%,
      #1d4ed8 0%,
      transparent 60%
    ),
    radial-gradient(1000px 700px at 90% 90%, #7c3aed 0%, transparent 65%),
    var(--bg);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: clamp(16px, 3vw, 40px);
  user-select: none;
}

h1 {
  width: 100%;
  max-width: 980px;
  margin: 0 0 16px 0;
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.1;
  text-align: center;
  font-size: clamp(24px, 3.2vw, 40px);
  text-shadow: 0 2px 14px rgba(0, 0, 0, 0.35);
}

.container {
  width: min(980px, 100%);
  background: var(--card);
  border: 1px solid rgba(148, 163, 184, 0.18);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  backdrop-filter: saturate(140%) blur(10px);
  padding: clamp(16px, 2.5vw, 28px);
  display: flex;
  flex-direction: column;
  gap: clamp(12px, 2vw, 18px);
}

/* Top input row */
.entrance-Section {
  display: flex;
  gap: 10px;
  align-items: center;
}

.enterNote {
  flex: 1 1 auto;
  min-width: 0;
  height: var(--row-h);
  padding: 0 16px;
  font-size: clamp(14px, 1.4vw, 16px);
  color: var(--text);
  background: linear-gradient(
    180deg,
    rgba(255, 255, 255, 0.08),
    rgba(255, 255, 255, 0.02)
  );
  border: 1px solid rgba(148, 163, 184, 0.25);
  border-radius: calc(var(--radius) - 8px);
  outline: none;
  transition: border-color 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}
.enterNote::placeholder {
  color: var(--muted);
}
.enterNote:focus {
  border-color: var(--ring);
  box-shadow: 0 0 0 4px rgba(147, 197, 253, 0.25);
  background: linear-gradient(
    180deg,
    rgba(255, 255, 255, 0.12),
    rgba(255, 255, 255, 0.04)
  );
}

.enterBtn {
  flex: 0 0 auto;
  width: var(--row-h);
  height: var(--row-h);
  border: none;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--primary), var(--primary-600));
  color: white;
  font-size: 28px;
  font-weight: 700;
  display: grid;
  place-items: center;
  cursor: pointer;
  box-shadow: 0 6px 16px rgba(37, 99, 235, 0.35);
  transition: transform 0.18s ease, box-shadow 0.2s ease, filter 0.2s ease;
}
.enterBtn:hover {
  transform: translateY(-1px);
  filter: saturate(110%);
}
.enterBtn:active {
  transform: translateY(0);
  box-shadow: 0 4px 10px rgba(37, 99, 235, 0.28);
}
hr {
  height: 1px;
  border: none;
  background: linear-gradient(
    90deg,
    transparent,
    rgba(148, 163, 184, 0.45),
    transparent
  );
  margin: 2px 0 0 0;
}

/* Output list */
.output-Section {
  display: flex;
  flex-direction: column;
  gap: 10px;
  max-height: clamp(40vh, 52vh, 60vh);
  overflow: auto;
  padding-right: 2px; /* space for scrollbar */
}

/* Custom scrollbar (WebKit) */
.output-Section::-webkit-scrollbar {
  width: 10px;
}
.output-Section::-webkit-scrollbar-track {
  background: transparent;
}
.output-Section::-webkit-scrollbar-thumb {
  background: linear-gradient(
    180deg,
    rgba(148, 163, 184, 0.45),
    rgba(148, 163, 184, 0.25)
  );
  border-radius: 999px;
}

/* Each note row */
.notes {
  display: grid;
  grid-template-columns: 64px 1fr var(--row-h);
  align-items: center;
  gap: 10px;
  background: linear-gradient(
    180deg,
    rgba(255, 255, 255, 0.06),
    rgba(255, 255, 255, 0.02)
  );
  border: 1px solid rgba(148, 163, 184, 0.22);
  border-radius: 12px;
  padding: 8px;
  box-shadow: var(--inner-shadow);
}

/* index pill */
.notes > span {
  display: grid;
  place-items: center;
  height: var(--row-h);
  border-radius: 10px;
  background: linear-gradient(
    180deg,
    rgba(148, 163, 184, 0.22),
    rgba(148, 163, 184, 0.08)
  );
  border: 1px solid rgba(148, 163, 184, 0.28);
  color: var(--text);
  font-weight: 700;
  font-size: 16px;
}

/* editable input */
.notes input {
  height: var(--row-h);
  width: 100%;
  border: none;
  border-radius: 10px;
  background: linear-gradient(
    180deg,
    rgba(255, 255, 255, 0.08),
    rgba(255, 255, 255, 0.02)
  );
  color: var(--text);
  padding: 0 14px;
  font-size: clamp(14px, 1.4vw, 16px);
  outline: none;
  transition: box-shadow 0.2s ease, background 0.2s ease;
}
.notes input:focus {
  box-shadow: 0 0 0 4px rgba(147, 197, 253, 0.2);
  background: linear-gradient(
    180deg,
    rgba(255, 255, 255, 0.12),
    rgba(255, 255, 255, 0.04)
  );
}

/* remove button */
.removeBtn {
  height: var(--row-h);
  width: var(--row-h);
  border: none;
  border-radius: 10px;
  background: linear-gradient(135deg, #fb7185, #ef4444);
  color: #fff;
  font-size: 28px; /* keep text big */
  line-height: 1;
  display: grid;
  place-items: center;
  cursor: pointer;
  transition: transform 0.15s ease, filter 0.2s ease, box-shadow 0.2s ease;
  box-shadow: 0 6px 16px rgba(239, 68, 68, 0.32);
}
.removeBtn:hover {
  transform: translateY(-1px);
  filter: saturate(115%);
}
.removeBtn:active {
  transform: translateY(0);
}

/* Focus visible for a11y */
.enterBtn:focus-visible,
.removeBtn:focus-visible,
.enterNote:focus-visible,
.notes input:focus-visible {
  outline: none;
  box-shadow: 0 0 0 4px rgba(147, 197, 253, 0.35);
}

/* Small screens */
@media (max-width: 520px) {
  .notes {
    grid-template-columns: 48px 1fr 48px;
    padding: 6px;
  }
  :root {
    --row-h: 48px;
  }
  .enterBtn {
    border-radius: 12px;
    font-size: 24px;
  }
}

/* Extra small */
@media (max-width: 360px) {
  .entrance-Section {
    flex-direction: column;
  }
  .enterBtn {
    width: 100%;
  }
}