* { margin: 0; padding: 0; box-sizing: border-box; }

:root {
  color-scheme: light;
  --bg: #ffffff;
  --card: #ffffff;
  --input: #f1fbfa;
  --accent: #3fc0b2;
  --accent-strong: #2b9a8e;
  --accent-hover: #1f7d73;
  --accent-deep: #186d63;
  --accent-soft: rgba(63, 192, 178, 0.14);
  --gold: #d97706;
  --cyan: #1f7d73;
  --text: #232f2e;
  --muted: #63716f;
  --border: #e2ecea;
  --error: #dc2626;
  --ok: #1f7d73;
}

html { scroll-behavior: smooth; }

body {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  background:
    radial-gradient(1100px 620px at 88% -12%, rgba(63, 192, 178, 0.24), transparent 62%),
    radial-gradient(900px 560px at -12% 26%, rgba(63, 192, 178, 0.12), transparent 58%),
    radial-gradient(760px 700px at 55% 112%, rgba(217, 119, 6, 0.08), transparent 62%),
    radial-gradient(rgba(63, 192, 178, 0.12) 1px, transparent 1.6px) 0 0 / 24px 24px,
    linear-gradient(165deg, #ffffff 0%, #f3fbfa 48%, #e7f6f4 100%);
  background-attachment: fixed;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  color: var(--text);
}

a { color: inherit; }

/* ---------- Header ---------- */
.site-header {
  width: 100%;
  max-width: 1100px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 16px;
  padding: 14px 22px;
  background: rgba(255, 255, 255, 0.66);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid rgba(255, 255, 255, 0.9);
  border-radius: 20px;
  box-shadow: 0 10px 34px rgba(23, 90, 84, 0.12);
}

.logo {
  display: flex;
  align-items: center;
  gap: 9px;
  font-size: 1.35rem;
  font-weight: 700;
  text-decoration: none;
  letter-spacing: 0.3px;
}

.logo-mark { width: 34px; height: 34px; display: block; flex-shrink: 0; }

.accent {
  background: linear-gradient(90deg, #1f7d73, #3fc0b2);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.nav { display: flex; flex-wrap: wrap; gap: 4px; }

.nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.93rem;
  padding: 8px 13px;
  border-radius: 8px;
  transition: color 0.2s, background 0.2s;
}

.nav a:hover, .nav a.active {
  color: var(--text);
  background: var(--accent-soft);
}

/* ---------- Hero / index ---------- */
.wrap { width: 100%; max-width: 1100px; padding: 0 20px; }

.hero { text-align: center; padding: 34px 10px 8px; }

.hero h1 {
  font-size: clamp(1.8rem, 4.5vw, 2.8rem);
  line-height: 1.2;
  background: linear-gradient(90deg, #1f7d73, #3fc0b2);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero p {
  color: var(--muted);
  margin: 12px auto 22px;
  max-width: 640px;
  font-size: 1.02rem;
}

.search {
  max-width: 440px;
  width: 100%;
  margin: 0 auto;
  position: relative;
}

.search input {
  width: 100%;
  background: var(--input);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 999px;
  padding: 13px 20px;
  font-size: 1rem;
  text-align: center;
}

.search input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(63, 192, 178, 0.5);
}

.no-results {
  display: none;
  text-align: center;
  color: var(--muted);
  padding: 30px 0;
}

/* ---------- Category sections ---------- */
.cat-section { margin-top: 42px; scroll-margin-top: 20px; }

.cat-head {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 10px;
}

.cat-head h2 { font-size: 1.4rem; }

.cat-head .emoji { font-size: 1.5rem; }

.tag {
  background: rgba(217, 119, 6, 0.14);
  color: #a16207;
  font-size: 0.78rem;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 999px;
  margin-left: auto;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(235px, 1fr));
  gap: 14px;
}

.calc-card {
  display: block;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 18px;
  text-decoration: none;
  transition: transform 0.15s, border-color 0.15s, box-shadow 0.15s;
}

.calc-card:hover {
  transform: translateY(-4px);
  border-color: var(--accent);
  box-shadow: 0 12px 26px rgba(23, 90, 84, 0.16);
}

.calc-card h3 {
  font-size: 1.02rem;
  margin-bottom: 6px;
  color: var(--text);
}

.calc-card p { font-size: 0.85rem; color: var(--muted); line-height: 1.5; }

/* ---------- Breadcrumb ---------- */
.crumbs {
  font-size: 0.87rem;
  color: var(--muted);
  padding: 4px 0 16px;
}

.crumbs a { color: var(--muted); text-decoration: none; }
.crumbs a:hover { color: var(--text); text-decoration: underline; }
.crumbs span { color: var(--text); }

/* ---------- Calculator page ---------- */
.calc-page {
  width: 100%;
  max-width: 640px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 32px 30px;
  box-shadow: 0 20px 50px rgba(23, 90, 84, 0.11);
}

.calc-page h1 { font-size: 1.75rem; margin-bottom: 8px; }

.lead { color: var(--muted); font-size: 0.95rem; margin-bottom: 22px; line-height: 1.6; }

.calc-form { display: flex; flex-direction: column; }

.row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 0 14px;
}

.field { display: flex; flex-direction: column; margin-bottom: 15px; }

.field label, .check, .group-label {
  font-size: 0.88rem;
  color: var(--muted);
  margin-bottom: 6px;
}

.field input, .field select, textarea.input {
  background: var(--input);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 11px 13px;
  color: var(--text);
  font-size: 1rem;
  font-family: inherit;
  transition: border-color 0.2s, box-shadow 0.2s;
  width: 100%;
}

.field input:focus, .field select:focus, textarea.input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(63, 192, 178, 0.5);
}

textarea.input { resize: vertical; min-height: 96px; line-height: 1.5; }

.check {
  display: flex;
  align-items: center;
  gap: 9px;
  margin-bottom: 12px;
  cursor: pointer;
}

.check input { width: 17px; height: 17px; accent-color: var(--accent); }

.hint { font-size: 0.8rem; color: var(--muted); margin: -6px 0 14px; }

.btn {
  font-size: 1rem;
  font-weight: 600;
  padding: 13px;
  border: none;
  border-radius: 10px;
  background: var(--accent-hover);
  color: #fff;
  cursor: pointer;
  transition: background 0.2s, transform 0.1s;
  margin-top: 4px;
}

.btn:hover { background: var(--accent-hover); }
.btn:active { transform: scale(0.98); }

.btn-ghost {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--muted);
  padding: 9px 14px;
  font-size: 0.9rem;
}

.btn-ghost:hover { background: var(--border); color: var(--text); }

.btn-row { display: flex; gap: 10px; flex-wrap: wrap; }
.btn-row .btn { flex: 1; margin-top: 0; }

/* ---------- Results ---------- */
.calc-result {
  margin-top: 24px;
  border-top: 1px solid var(--border);
  padding-top: 22px;
  animation: fade 0.35s ease;
}

@keyframes fade {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.headline {
  text-align: center;
  font-size: clamp(1.6rem, 5vw, 2.2rem);
  font-weight: 700;
  color: var(--cyan);
  margin-bottom: 4px;
  word-break: break-word;
}

.headline-label {
  text-align: center;
  color: var(--muted);
  font-size: 0.88rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 18px;
}

.stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 10px;
}

.stat {
  background: var(--input);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 13px 10px;
  text-align: center;
}

.stat .v {
  display: block;
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text);
  word-break: break-word;
}

.stat .v.cyan { color: var(--cyan); }
.stat .v.green { color: var(--ok); }

.stat .l {
  display: block;
  font-size: 0.72rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-top: 5px;
}

.alert {
  background: rgba(220, 38, 38, 0.07);
  border: 1px solid rgba(220, 38, 38, 0.30);
  color: var(--error);
  padding: 11px 14px;
  border-radius: 10px;
  font-size: 0.92rem;
  text-align: center;
}

.note {
  font-size: 0.87rem;
  color: var(--muted);
  margin-top: 14px;
  line-height: 1.6;
}

.list {
  font-size: 0.93rem;
  line-height: 1.9;
  color: var(--text);
  margin-top: 14px;
}

.list strong { color: var(--muted); font-weight: 600; }

.table-wrap { max-height: 340px; overflow: auto; margin-top: 16px; border: 1px solid var(--border); border-radius: 10px; }

table.table { width: 100%; border-collapse: collapse; font-size: 0.86rem; }

.table th, .table td { padding: 9px 12px; text-align: right; white-space: nowrap; }

.table th {
  background: var(--input);
  color: var(--muted);
  text-transform: uppercase;
  font-size: 0.72rem;
  letter-spacing: 0.5px;
  position: sticky;
  top: 0;
}

.table td { border-top: 1px solid var(--border); }
.table th:first-child, .table td:first-child { text-align: left; }
.table tr:nth-child(even) td { background: rgba(63, 192, 178, 0.07); }

/* ---------- Info / related ---------- */
.howto, .related {
  width: 100%;
  max-width: 1100px;
  margin-top: 34px;
}

.howto-inner, .related-inner {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 24px 26px;
}

.howto h2, .related h2 { font-size: 1.15rem; margin-bottom: 12px; color: var(--accent-strong); }

.howto p { color: var(--muted); font-size: 0.93rem; line-height: 1.75; }

.formula {
  display: inline-block;
  background: var(--input);
  border: 1px solid var(--border);
  border-left: 4px solid var(--gold);
  border-radius: 8px;
  padding: 8px 14px;
  margin-top: 12px;
  color: var(--cyan);
  font-family: Consolas, "Courier New", monospace;
  font-size: 0.92rem;
}

/* ---------- Footer ---------- */
.site-footer {
  width: 100%;
  max-width: 1100px;
  margin-top: 46px;
  padding: 30px 20px 34px;
  border-top: 2px solid var(--border);
  border-image: linear-gradient(90deg, #3fc0b2, #d97706, rgba(217, 119, 6, 0)) 1;
}

.sitemap {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 26px;
  margin-bottom: 26px;
}

.sitemap h4 {
  font-size: 0.95rem;
  margin-bottom: 10px;
  color: var(--text);
}

.sitemap ul { list-style: none; }

.sitemap li { margin-bottom: 6px; }

.sitemap a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.85rem;
  transition: color 0.2s;
}

.sitemap a:hover { color: var(--cyan); }

.footer-bottom { text-align: center; border-top: 1px solid var(--border); padding-top: 20px; }

.footer-links { display: flex; justify-content: center; flex-wrap: wrap; gap: 6px; margin-bottom: 12px; }

.footer-links a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.87rem;
  padding: 7px 13px;
  border-radius: 8px;
}

.footer-links a:hover { color: var(--text); background: rgba(63, 192, 178, 0.14); }

.copyright { font-size: 0.87rem; color: var(--muted); }
.made-with { font-size: 0.8rem; color: var(--muted); margin-top: 6px; }

/* ---------- Homepage: category link lists (calculator.net style) ---------- */
.calc-page { margin: 0 auto; }

.cat-title h2 { font-size: 1.22rem; }

.cat-title p { font-size: 0.86rem; color: var(--muted); margin-top: 3px; }

.cat-thumb {
  width: 60px;
  height: 60px;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.8rem;
  flex-shrink: 0;
  box-shadow: 0 8px 20px rgba(63, 192, 178, 0.22);
}

.cat-head { border-bottom: 1px solid var(--border); padding-bottom: 14px; margin-bottom: 14px; }

.calc-links {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(215px, 1fr));
  gap: 8px;
}

.calc-links .calc-card {
  padding: 11px 30px 11px 14px;
  font-size: 0.93rem;
  border-radius: 10px;
  position: relative;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.calc-links .calc-card::after {
  content: "›";
  position: absolute;
  right: 12px;
  top: 50%;
  transform: translate(-6px, -50%);
  opacity: 0;
  color: var(--cyan);
  transition: opacity 0.2s, transform 0.2s;
}

.calc-links .calc-card:hover { transform: translateX(6px); }

.calc-links .calc-card:hover::after { opacity: 1; transform: translate(0, -50%); }

/* ---------- Featured slider (the slidy part) ---------- */
.slider {
  position: relative;
  margin-top: 30px;
  border-radius: 18px;
  overflow: hidden;
  border: 1px solid var(--border);
  box-shadow: 0 16px 40px rgba(23, 90, 84, 0.15);
}

.slider-window { overflow: hidden; }

.slider-track { display: flex; transition: transform 0.65s cubic-bezier(0.65, 0, 0.35, 1); }

.slide {
  min-width: 100%;
  display: flex;
  align-items: center;
  gap: 22px;
  padding: 36px 70px 36px 34px;
  text-decoration: none;
  color: #292524;
}

.slide-emoji { font-size: 3.1rem; filter: drop-shadow(0 5px 10px rgba(24, 109, 99, 0.25)); }

.slide-text h3 { font-size: 1.5rem; margin-bottom: 6px; }

.slide-text p { font-size: 0.95rem; opacity: 0.92; max-width: 520px; line-height: 1.5; }

.slide-cta {
  display: inline-block;
  margin-top: 13px;
  background: rgba(255, 255, 255, 0.8);
  border: 1px solid var(--accent);
  padding: 8px 17px;
  border-radius: 999px;
  font-size: 0.88rem;
  font-weight: 600;
  transition: background 0.2s, transform 0.2s;
}

.slide:hover .slide-cta { background: #fff; transform: translateX(5px); }

.slider-btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 38px;
  height: 38px;
  border-radius: 50%;
  border: 1px solid #99e6dc;
  background: rgba(255, 255, 255, 0.85);
  color: var(--accent-strong);
  font-size: 1.3rem;
  line-height: 1;
  cursor: pointer;
  transition: background 0.2s;
  z-index: 2;
}

.slider-btn:hover { background: #fff; }
.slider-btn.prev { left: 12px; }
.slider-btn.next { right: 12px; }

.slider-dots {
  position: absolute;
  bottom: 12px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 7px;
}

.slider-dots button {
  width: 9px;
  height: 9px;
  border-radius: 999px;
  border: none;
  background: rgba(63, 192, 178, 0.35);
  cursor: pointer;
  padding: 0;
  transition: width 0.25s, background 0.25s;
}

.slider-dots button.active { background: var(--accent-strong); width: 24px; }

/* ---------- Scroll reveal ---------- */
.reveal { opacity: 0; transform: translateY(30px); transition: opacity 0.6s ease, transform 0.6s ease; }
.reveal.is-visible { opacity: 1; transform: none; }

/* ---------- Scientific keypad ---------- */
.keypad { display: grid; grid-template-columns: repeat(5, 1fr); gap: 8px; margin: 4px 0 16px; }

.key {
  background: var(--input);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 10px;
  padding: 12px 0;
  font-size: 1rem;
  cursor: pointer;
  font-family: inherit;
  transition: background 0.15s, transform 0.1s;
}

.key:hover { background: var(--border); }
.key:active { transform: scale(0.95); }

.key-wide {
  grid-column: span 2;
  background: rgba(220, 38, 38, 0.07);
  border-color: rgba(220, 38, 38, 0.30);
  color: #b91c1c;
}

.key-eq { background: var(--accent-hover); border-color: var(--accent-hover); color: #fff; font-weight: 700; }
.key-eq:hover { background: var(--accent-deep); border-color: var(--accent-deep); }

/* ---------- Password list ---------- */
.pw-list { display: grid; gap: 8px; }

.pw {
  background: var(--input);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 9px 13px;
  font-family: Consolas, "Courier New", monospace;
  font-size: 0.95rem;
  letter-spacing: 0.5px;
  word-break: break-all;
  color: var(--accent-strong);
}

/* ---------- About block ---------- */
.about { width: 100%; max-width: 1100px; margin-top: 42px; }
.about .howto-inner p + p { margin-top: 12px; }
.about a { color: var(--cyan); }

/* ---------- Responsive ---------- */
@media (max-width: 640px) {
  .calc-page { padding: 24px 18px; }
  .site-header { justify-content: center; text-align: center; }
  .nav { justify-content: center; }
  .howto-inner, .related-inner { padding: 20px 16px; }
  .slide { padding: 26px 54px 30px 20px; gap: 13px; }
  .slide-emoji { font-size: 2.2rem; }
  .slide-text h3 { font-size: 1.12rem; }
  .slide-text p { font-size: 0.85rem; }
  .slider-btn { width: 32px; height: 32px; font-size: 1.05rem; }
  .cat-thumb { width: 48px; height: 48px; font-size: 1.4rem; border-radius: 12px; }
  .calc-links { grid-template-columns: 1fr; }
}

/* ---------- Dark mode ---------- */
[data-theme="dark"] {
  color-scheme: dark;
  --bg: #10140c;
  --card: #1a2013;
  --input: #141a0e;
  --accent: #a3e635;
  --accent-strong: #4d7c0f;
  --accent-hover: #3f6212;
  --accent-deep: #365314;
  --gold: #f59e0b;
  --cyan: #a3e635;
  --text: #e9e7db;
  --muted: #a6ab95;
  --border: #313d26;
  --error: #f87171;
  --ok: #a3e635;

  --page-bg:
    radial-gradient(1100px 620px at 88% -12%, rgba(163, 230, 53, 0.10), transparent 62%),
    radial-gradient(900px 560px at -12% 26%, rgba(45, 212, 191, 0.07), transparent 58%),
    radial-gradient(760px 700px at 55% 112%, rgba(245, 158, 11, 0.07), transparent 62%),
    radial-gradient(rgba(163, 230, 53, 0.09) 1px, transparent 1.6px) 0 0 / 24px 24px,
    linear-gradient(165deg, #12160d 0%, #161c10 48%, #10150b 100%);
  --grad-accent: linear-gradient(90deg, #a3e635, #65a30d);
  --grad-heading: linear-gradient(90deg, #bef264, #65a30d);
  --header-bg: rgba(26, 32, 19, 0.78);
  --header-border: rgba(163, 230, 53, 0.14);
  --hover-soft: rgba(163, 230, 53, 0.10);
  --ring: rgba(163, 230, 53, 0.5);
  --tag-bg: rgba(245, 158, 11, 0.16);
  --tag-color: #fbbf24;
  --shadow-card: 0 20px 50px rgba(0, 0, 0, 0.5);
  --shadow-soft: 0 12px 26px rgba(0, 0, 0, 0.4);
  --shadow-thumb: 0 8px 20px rgba(0, 0, 0, 0.45);
  --stripe: rgba(163, 230, 53, 0.05);
  --heading2: #a3e635;
  --faint: #878c7a;
  --alert-bg: rgba(248, 113, 113, 0.12);
  --alert-border: rgba(248, 113, 113, 0.4);
  --danger-soft: rgba(248, 113, 113, 0.12);
  --danger-border: rgba(248, 113, 113, 0.35);
  --danger-text: #fca5a5;
  --pw: #a3e635;
  --slide-bg: linear-gradient(135deg, #243017, #171e0f);
  --slide-text: #f3f2e7;
  --dot: rgba(163, 230, 53, 0.35);
  --dot-active: #a3e635;
}

[data-theme="dark"] body {
  background: var(--page-bg);
  background-attachment: fixed;
}
[data-theme="dark"] .accent { background: var(--grad-accent); }
[data-theme="dark"] .hero h1 { background: var(--grad-heading); }
[data-theme="dark"] .site-header {
  background: var(--header-bg);
  border-color: var(--header-border);
  box-shadow: 0 10px 34px rgba(0, 0, 0, 0.45);
}
[data-theme="dark"] .nav a:hover, [data-theme="dark"] .nav a.active,
[data-theme="dark"] .footer-links a:hover { background: var(--hover-soft); }
[data-theme="dark"] .search input:focus,
[data-theme="dark"] .field input:focus,
[data-theme="dark"] .field select:focus,
[data-theme="dark"] textarea.input:focus { box-shadow: 0 0 0 3px var(--ring); }
[data-theme="dark"] .tag { background: var(--tag-bg); color: var(--tag-color); }
[data-theme="dark"] .calc-card:hover { box-shadow: var(--shadow-soft); }
[data-theme="dark"] .calc-page { box-shadow: var(--shadow-card); }
[data-theme="dark"] .table tr:nth-child(even) td { background: var(--stripe); }
[data-theme="dark"] .howto h2, [data-theme="dark"] .related h2 { color: var(--heading2); }
[data-theme="dark"] .made-with { color: var(--faint); }
[data-theme="dark"] .alert { background: var(--alert-bg); border-color: var(--alert-border); }
[data-theme="dark"] .key-wide { background: var(--danger-soft); border-color: var(--danger-border); color: var(--danger-text); }
[data-theme="dark"] .pw { color: var(--pw); }
[data-theme="dark"] .cat-thumb { box-shadow: var(--shadow-thumb); }
[data-theme="dark"] .slider { box-shadow: var(--shadow-card); }
[data-theme="dark"] .slide { background: var(--slide-bg) !important; color: var(--slide-text); }
[data-theme="dark"] .slide-cta { color: #1a2e05; }
[data-theme="dark"] .slider-dots button { background: var(--dot); }
[data-theme="dark"] .slider-dots button.active { background: var(--dot-active); }

/* ---------- Theme toggle button ---------- */
.theme-toggle {
  width: 40px;
  height: 40px;
  flex: 0 0 auto;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--card);
  cursor: pointer;
  font-size: 1.05rem;
  line-height: 1;
  display: grid;
  place-items: center;
  transition: transform 0.25s, background 0.2s, border-color 0.2s;
}
.theme-toggle:hover { transform: rotate(25deg) scale(1.07); border-color: var(--accent); }
[data-theme="dark"] .theme-toggle { background: var(--input); }
.theme-toggle .icon-sun { display: none; }
.theme-toggle .icon-moon { display: inline; }
[data-theme="dark"] .theme-toggle .icon-sun { display: inline; }
[data-theme="dark"] .theme-toggle .icon-moon { display: none; }