/* Use predictable sizing for every element. */
* {
  box-sizing: border-box;
}

:root {
  color-scheme: dark;

  --background: #080c14;
  --surface: #111827;
  --surface-light: #182235;
  --border: #2b3952;
  --text: #edf4ff;
  --muted: #9eabc0;
  --accent: #4ca6ff;
  --accent-hover: #78bcff;
  --success: #49d17d;
  --danger: #ff6b73;
}

/* Always respect the HTML hidden attribute. */
[hidden] {
  display: none !important;
}

body {
  margin: 0;
  min-height: 100vh;

  background:
    radial-gradient(
      circle at top,
      #17253b 0%,
      var(--background) 42%
    );

  color: var(--text);

  font-family:
    Inter,
    ui-sans-serif,
    system-ui,
    -apple-system,
    BlinkMacSystemFont,
    "Segoe UI",
    sans-serif;
}

button,
input {
  font: inherit;
}

button {
  cursor: pointer;
}

/* Main page layout. */
.page-shell {
  display: flex;
  flex-direction: column;
  align-items: center;

  min-height: 100vh;
  padding: 32px 20px;
}

/* Main site heading area. */
.site-header {
  width: min(760px, 100%);
  margin-bottom: 18px;
}

.eyebrow {
  margin: 0 0 8px;

  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.16em;
}

h1,
h2,
h3,
h4,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 12px;

  font-size: clamp(2rem, 5vw, 3.25rem);
  line-height: 1.05;
}

.description {
  max-width: 62ch;
  margin-bottom: 0;

  color: var(--muted);
  line-height: 1.6;
}

/* Tool navigation tabs. */
.tool-tabs {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 8px;

  width: min(760px, 100%);
  margin-bottom: 14px;
}

.tool-tab {
  padding: 10px 14px;

  border: 1px solid var(--border);
  border-radius: 8px;

  background: #0d1523;
  color: var(--muted);

  font-weight: 700;
}

.tool-tab:hover {
  background: var(--surface-light);
  color: var(--text);
}

.tool-tab.active {
  border-color: var(--accent);
  background: rgba(76, 166, 255, 0.12);
  color: var(--accent);
}

/* Shared tool panel layout. */
.tool-panel {
  width: min(760px, 100%);
  padding: 32px;

  border: 1px solid var(--border);
  border-radius: 14px;

  background: rgba(17, 24, 39, 0.96);

  box-shadow:
    0 20px 60px rgba(0, 0, 0, 0.35);
}

.tool-header h2 {
  margin-bottom: 8px;
  font-size: 1.6rem;
}

.tool-description {
  margin-bottom: 24px;

  color: var(--muted);
  line-height: 1.6;
}

/* Shared form styles. */
.tool-form label {
  display: block;
  margin-bottom: 8px;

  font-weight: 650;
}

.input-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 12px;
}

input {
  min-width: 0;
  padding: 13px 14px;

  border: 1px solid var(--border);
  border-radius: 8px;

  background: #0b1220;
  color: var(--text);

  outline: none;
}

input:focus {
  border-color: var(--accent);

  box-shadow:
    0 0 0 3px rgba(76, 166, 255, 0.16);
}

button[type="submit"] {
  padding: 13px 18px;

  border: 0;
  border-radius: 8px;

  background: var(--accent);
  color: #04101c;

  font-weight: 750;
}

button[type="submit"]:hover {
  background: var(--accent-hover);
}

button:disabled {
  cursor: wait;
  opacity: 0.65;
}

/* Loading, success, and error message area. */
.status-message {
  min-height: 24px;
  margin: 18px 0 0;

  color: var(--muted);
}

.status-message.error {
  color: var(--danger);
}

/* Shared result panel. */
.result-panel {
  margin-top: 24px;
  padding: 22px;

  border: 1px solid var(--border);
  border-radius: 10px;

  background: var(--surface-light);
}

.result-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;

  margin-bottom: 18px;
}

.result-heading h3 {
  margin-bottom: 0;
  font-size: 1.25rem;
}

/* Shared status badges. */
.status-badge,
.hostname-badge {
  padding: 5px 10px;

  border-radius: 999px;

  font-size: 0.82rem;
  font-weight: 750;
}

.status-badge.online {
  background: rgba(73, 209, 125, 0.14);
  color: var(--success);
}

.status-badge.offline {
  background: rgba(255, 107, 115, 0.14);
  color: var(--danger);
}

.hostname-badge {
  background: rgba(76, 166, 255, 0.12);
  color: var(--accent);

  overflow-wrap: anywhere;
}

/* Shared result grid. */
.result-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;

  margin: 0;
}

.result-grid div {
  padding: 14px;

  border: 1px solid var(--border);
  border-radius: 8px;

  background: #0d1523;
}

.result-grid dt,
.final-url-block span,
.certificate-detail-block span {
  margin-bottom: 6px;

  color: var(--muted);
  font-size: 0.82rem;
}

.result-grid dd {
  margin: 0;

  font-weight: 700;
  overflow-wrap: anywhere;
}

/* Final URL display. */
.final-url-block {
  display: grid;
  gap: 5px;

  margin-top: 14px;
  padding: 14px;

  border: 1px solid var(--border);
  border-radius: 8px;

  background: #0d1523;
}

.final-url-block a {
  color: var(--accent);
  overflow-wrap: anywhere;
}

/* DNS result styles. */
.dns-records {
  display: grid;
  gap: 12px;
}

.dns-record-group {
  border: 1px solid var(--border);
  border-radius: 8px;

  background: #0d1523;
  overflow: hidden;
}

.dns-record-group h4 {
  margin: 0;
  padding: 11px 14px;

  border-bottom: 1px solid var(--border);

  color: var(--accent);
  font-size: 0.9rem;
  letter-spacing: 0.08em;
}

.dns-record-list {
  margin: 0;
  padding: 12px 14px 12px 34px;
}

.dns-record-list li {
  margin: 5px 0;
  overflow-wrap: anywhere;
}

.empty-record {
  margin: 0;
  padding: 12px 14px;

  color: var(--muted);
}

.dns-checked-at {
  margin: 14px 0 0;

  color: var(--muted);
  font-size: 0.84rem;
}

/* SSL certificate result styles. */
.certificate-detail-block {
  display: grid;
  gap: 6px;

  margin-top: 14px;
  padding: 14px;

  border: 1px solid var(--border);
  border-radius: 8px;

  background: #0d1523;
}

.certificate-detail-block p {
  margin: 0;
  overflow-wrap: anywhere;
}

.certificate-detail-block code {
  color: var(--accent);

  font-family:
    "Cascadia Code",
    "Courier New",
    monospace;

  line-height: 1.5;
  overflow-wrap: anywhere;
  white-space: normal;
}

.certificate-error {
  border-color: rgba(255, 107, 115, 0.5);
}

/* HTTP header result sections. */
.headers-section {
  margin-top: 22px;
}

.headers-section h4 {
  margin: 0 0 12px;
  font-size: 1rem;
}

.security-header-results,
.all-header-results {
  display: grid;
  gap: 10px;
}

/* One security header result card. */
.security-header-item {
  display: grid;
  gap: 7px;

  padding: 14px;

  border: 1px solid var(--border);
  border-radius: 8px;

  background: #0d1523;
}

.security-header-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.security-header-heading strong {
  overflow-wrap: anywhere;
}

.security-header-purpose,
.security-header-value {
  margin: 0;

  color: var(--muted);
  line-height: 1.5;
  overflow-wrap: anywhere;
}

.security-header-value code {
  color: var(--accent);
  white-space: normal;
}

/* Present or missing security header badge. */
.header-status {
  flex-shrink: 0;

  padding: 4px 8px;

  border-radius: 999px;

  font-size: 0.76rem;
  font-weight: 750;
}

.header-status.present {
  background: rgba(73, 209, 125, 0.14);
  color: var(--success);
}

.header-status.missing {
  background: rgba(255, 107, 115, 0.14);
  color: var(--danger);
}

/* One raw response header row. */
.response-header-item {
  display: grid;
  grid-template-columns: minmax(150px, 220px) minmax(0, 1fr);
  gap: 16px;

  padding: 12px 14px;

  border: 1px solid var(--border);
  border-radius: 8px;

  background: #0d1523;
}

.response-header-name {
  color: var(--accent);

  font-family:
    "Cascadia Code",
    "Courier New",
    monospace;

  font-weight: 700;
  overflow-wrap: anywhere;
}

.response-header-value {
  color: var(--text);
  overflow-wrap: anywhere;
}

/* Tablet layout. */
@media (max-width: 780px) {
  .tool-tabs {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

/* Phone layout. */
@media (max-width: 640px) {
  .page-shell {
    padding: 24px 14px;
  }

  .tool-panel {
    padding: 24px 18px;
  }

  .tool-tabs {
    grid-template-columns: 1fr;
  }

  .tool-tab {
    width: 100%;
  }

  .input-row {
    grid-template-columns: 1fr;
  }

  .result-grid {
    grid-template-columns: 1fr;
  }

  button[type="submit"] {
    width: 100%;
  }

  .result-heading {
    align-items: flex-start;
    flex-direction: column;
  }

  .response-header-item {
    grid-template-columns: 1fr;
    gap: 6px;
  }
}