:root {
  --bg: #f5f6f8;
  --surface: #ffffff;
  --text: #1a1d23;
  --text-muted: #5c6370;
  --border: #d8dbe0;
  --accent: #2563eb;
  --accent-text: #ffffff;
  --error: #c0392b;
  --error-bg: #fdecea;
  --table-stripe: #f0f2f5;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14161a;
    --surface: #1e2126;
    --text: #e6e8eb;
    --text-muted: #9aa1ab;
    --border: #33373f;
    --accent: #3b82f6;
    --accent-text: #ffffff;
    --error: #f87171;
    --error-bg: #3a1f1f;
    --table-stripe: #262a31;
  }
}

* { box-sizing: border-box; }

[hidden] { display: none !important; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
}

.app-header {
  padding: 1.5rem 1.5rem 0.5rem;
  text-align: center;
}
.app-header h1 { margin: 0 0 0.25rem; font-size: 1.6rem; }
.subtitle { margin: 0; color: var(--text-muted); font-size: 0.95rem; }

.tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  justify-content: center;
  padding: 1rem;
}
.tab-btn {
  padding: 0.5rem 1rem;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  border-radius: 999px;
  cursor: pointer;
  font-size: 0.9rem;
}
.tab-btn.active {
  background: var(--accent);
  color: var(--accent-text);
  border-color: var(--accent);
}

main {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 1rem 3rem;
}

.tab-panel { display: none; }
.tab-panel.active { display: block; }

.tab-panel h2 { margin-top: 0; }

.form-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
  flex-wrap: wrap;
}
.form-row label {
  flex: 0 0 220px;
  font-size: 0.9rem;
  color: var(--text-muted);
}
.form-row input, .form-row select {
  flex: 1 1 160px;
  padding: 0.45rem 0.6rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--surface);
  color: var(--text);
  font-size: 0.95rem;
  min-width: 0;
}

.calc-btn, .secondary-btn {
  padding: 0.55rem 1.2rem;
  border-radius: 6px;
  border: none;
  cursor: pointer;
  font-size: 0.95rem;
  margin: 0.5rem 0.5rem 0.5rem 0;
}
.calc-btn { background: var(--accent); color: var(--accent-text); }
.secondary-btn { background: var(--surface); color: var(--text); border: 1px solid var(--border); }

.error {
  background: var(--error-bg);
  color: var(--error);
  padding: 0.6rem 0.8rem;
  border-radius: 6px;
  font-size: 0.9rem;
}

.hint { color: var(--text-muted); font-size: 0.85rem; }

.result-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
  font-size: 0.9rem;
}
.result-table td {
  padding: 0.5rem 0.75rem;
  border-bottom: 1px solid var(--border);
}
.result-table tr:last-child td { border-bottom: none; }
.result-table tr:nth-child(even) { background: var(--table-stripe); }
.result-table td:first-child {
  color: var(--text-muted);
  width: 45%;
  font-size: 0.85rem;
}
.result-table td:last-child {
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  word-break: break-all;
}

.section-subheading {
  margin-top: 1.75rem;
  margin-bottom: 0;
  font-size: 1rem;
  color: var(--text-muted);
}

.dns-table td:first-child { width: 30%; color: var(--text); font-size: 0.9rem; }
.dns-table td:not(:first-child) {
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  word-break: break-all;
}

.notes {
  color: var(--text-muted);
  font-size: 0.85rem;
  margin-top: 0.75rem;
}

.result-box {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1rem;
  margin-top: 1rem;
  font-size: 1rem;
}
.result-box .primary { font-size: 1.3rem; font-weight: 600; }
.result-box .secondary { color: var(--text-muted); margin-top: 0.25rem; }

.result-box .label { color: var(--text-muted); font-size: 0.85rem; }

/* ---------- Storage / RAM ---------- */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1rem 1.1rem;
  margin-bottom: 1.25rem;
}
.card h3 { margin: 0 0 0.5rem; font-size: 1.05rem; }
.card .hint { margin-top: 0; }
.card .result-box, .card .result-table { background: var(--bg); }

.muted-msg { color: var(--text-muted); font-size: 0.9rem; font-style: italic; }

.unit-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}
.unit-grid h4 { margin: 0.25rem 0 0; font-size: 0.9rem; }
.unit-grid h4 span { display: block; font-weight: normal; color: var(--text-muted); font-size: 0.8rem; }
.unit-table { margin-top: 0.4rem; }
.unit-table td:first-child {
  width: auto;
  text-align: right;
  color: var(--text);
  font-size: 0.9rem;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  word-break: break-all;
}
.unit-table td:last-child { width: 3.5rem; color: var(--text-muted); }
.unit-table tr.best td { font-weight: 700; color: var(--accent); }

.preset-chips { display: flex; flex-wrap: wrap; gap: 0.4rem; margin-bottom: 0.75rem; }
.chip {
  padding: 0.3rem 0.75rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--bg);
  color: var(--text);
  font-size: 0.85rem;
  cursor: pointer;
}
.chip:hover { border-color: var(--accent); color: var(--accent); }

.storage-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
  flex-wrap: wrap;
}
.storage-row input, .storage-row select {
  padding: 0.45rem 0.6rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--surface);
  color: var(--text);
  font-size: 0.95rem;
  min-width: 0;
}
.storage-row .qty-input { flex: 0 0 4.5rem; }
.storage-row .times { color: var(--text-muted); }
.storage-row .amount-input { flex: 1 1 5rem; }
.storage-row .unit-select { flex: 0 0 6rem; }
.storage-row .label-input { flex: 2 1 8rem; }
.storage-row .remove-row { background: none; border: none; color: var(--error); cursor: pointer; font-size: 1.2rem; padding: 0 0.4rem; }

@media (max-width: 560px) {
  .unit-grid { grid-template-columns: 1fr; }
  .form-row label { flex-basis: 100%; }
  .storage-row { padding-bottom: 0.5rem; border-bottom: 1px dashed var(--border); }
}

.app-footer {
  text-align: center;
  color: var(--text-muted);
  font-size: 0.8rem;
  padding: 1rem;
}
.app-footer p { margin: 0.2rem 0; }
.app-footer p:first-child { font-size: 0.9rem; font-style: italic; }