/* 深蓝商业科技风：以清晰度、可信感和移动端操作效率为优先。 */
:root {
  color-scheme: light;
  --navy-950: #061525;
  --navy-900: #0a2038;
  --navy-850: #0e2947;
  --navy-800: #123454;
  --blue-600: #1268c3;
  --blue-500: #2185e5;
  --blue-100: #e7f1fc;
  --mint-400: #42d7ad;
  --mint-100: #ddf8ef;
  --ink-900: #10243a;
  --ink-700: #40546a;
  --ink-600: #5b6d80;
  --surface: #ffffff;
  --canvas: #f3f6fa;
  --border: #d8e1eb;
  --border-strong: #b9c8d8;
  --error: #a52b36;
  --error-bg: #fff1f2;
  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --shadow: 0 14px 38px rgba(6, 21, 37, 0.08);
  --focus: #e89b22;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-width: 280px;
  padding-right: env(safe-area-inset-right);
  padding-bottom: env(safe-area-inset-bottom);
  padding-left: env(safe-area-inset-left);
  background: var(--canvas);
  color: var(--ink-900);
  font-family: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

button,
input {
  font: inherit;
}

a {
  color: inherit;
  text-decoration: none;
}

button,
a,
input {
  -webkit-tap-highlight-color: transparent;
}

button {
  cursor: pointer;
}

button:disabled {
  cursor: not-allowed;
}

[hidden] {
  display: none !important;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.container {
  width: min(calc(100% - 32px), 1120px);
  margin-inline: auto;
}

.skip-link {
  position: fixed;
  top: 8px;
  left: 8px;
  z-index: 100;
  padding: 10px 16px;
  border-radius: var(--radius-sm);
  background: var(--surface);
  color: var(--navy-950);
  transform: translateY(-150%);
}

.skip-link:focus {
  transform: translateY(0);
}

:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 3px;
}

.site-header {
  background: var(--navy-950);
  color: #fff;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.header-inner {
  min-height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-height: 44px;
  font-weight: 750;
  letter-spacing: -0.025em;
}

.brand-mark {
  display: grid;
  width: 34px;
  height: 34px;
  flex: 0 0 auto;
  place-items: center;
  border: 1px solid rgba(255, 255, 255, 0.22);
  border-radius: 9px;
  background: var(--navy-800);
  color: var(--mint-400);
  font-size: 0.78rem;
  letter-spacing: 0.02em;
}

.brand-name {
  font-size: 1rem;
  white-space: nowrap;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 2px;
}

.site-nav a {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  padding: 8px 10px;
  border-radius: 8px;
  color: #c9d6e4;
  font-size: 0.86rem;
  font-weight: 600;
}

.site-nav a[aria-current="page"] {
  color: #fff;
  background: rgba(255, 255, 255, 0.08);
}

/* 窄屏隐藏 Calculators：用两条类提高优先级，避免被 .site-nav a 的 display 覆盖成死规则。 */
.site-nav .nav-calculators {
  display: none;
}

.hero {
  padding: 40px 0;
  background: var(--navy-900);
  color: #fff;
}

.hero-inner {
  position: relative;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  min-height: 28px;
  margin: 0 0 18px;
  padding: 3px 10px;
  border: 1px solid rgba(66, 215, 173, 0.3);
  border-radius: 999px;
  background: rgba(66, 215, 173, 0.08);
  color: var(--mint-400);
  font-size: 0.72rem;
  font-weight: 750;
  letter-spacing: 0.13em;
  line-height: 1.4;
  text-transform: uppercase;
}

.hero h1,
.tool-hero h1,
.products-hero h1 {
  max-width: 780px;
  margin: 0;
  font-size: clamp(2rem, 8vw, 3.7rem);
  line-height: 1.08;
  letter-spacing: -0.045em;
}

.hero-subtitle {
  max-width: 660px;
  margin: 18px 0 0;
  color: #c6d4e3;
  font-size: 1rem;
}

.search-wrap {
  position: relative;
  max-width: 720px;
  margin-top: 28px;
}

.search-wrap svg {
  position: absolute;
  top: 50%;
  left: 17px;
  width: 20px;
  height: 20px;
  color: var(--ink-600);
  pointer-events: none;
  transform: translateY(-50%);
}

.search-input {
  width: 100%;
  min-height: 54px;
  padding: 13px 16px 13px 48px;
  border: 2px solid transparent;
  border-radius: 12px;
  background: #fff;
  color: var(--ink-900);
  font-size: 16px;
  box-shadow: 0 10px 28px rgba(0, 0, 0, 0.14);
}

.search-input::placeholder {
  color: #64768a;
}

.search-input:focus {
  border-color: var(--blue-500);
}

.section {
  padding: 36px 0;
}

.section-heading {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 20px;
}

.section-heading h2 {
  margin: 0;
  font-size: 1.45rem;
  line-height: 1.25;
  letter-spacing: -0.025em;
}

.section-heading p {
  margin: 0;
  color: var(--ink-600);
  font-size: 0.92rem;
}

.tool-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

.tool-card {
  display: flex;
  min-height: 174px;
  flex-direction: column;
  padding: 22px;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: var(--surface);
  box-shadow: 0 3px 10px rgba(6, 21, 37, 0.025);
  transition: border-color 160ms ease, box-shadow 160ms ease;
}

.tool-card h3 {
  margin: 0 0 8px;
  font-size: 1.12rem;
  line-height: 1.3;
  letter-spacing: -0.015em;
}

.tool-card p {
  margin: 0 0 20px;
  color: var(--ink-600);
  font-size: 0.9rem;
  line-height: 1.55;
}

.tool-card-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-top: auto;
  color: var(--blue-600);
  font-size: 0.88rem;
  font-weight: 750;
}

.tool-card-link span {
  font-size: 1.1rem;
}

.empty-state {
  padding: 26px;
  border: 1px dashed var(--border-strong);
  border-radius: var(--radius-md);
  color: var(--ink-600);
  text-align: center;
}

.product-strip {
  padding: 0 0 36px;
}

.product-strip-inner {
  display: flex;
  flex-direction: column;
  gap: 20px;
  padding: 24px;
  border-radius: var(--radius-md);
  background: var(--navy-850);
  color: #fff;
}

.product-strip h2 {
  margin: 0 0 6px;
  font-size: 1.3rem;
}

.product-strip p {
  margin: 0;
  color: #c6d4e3;
  font-size: 0.9rem;
}

.button {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 18px;
  border: 1px solid transparent;
  border-radius: 10px;
  background: var(--blue-600);
  color: #fff;
  font-weight: 700;
  line-height: 1.3;
  text-align: center;
  transition: background-color 160ms ease, border-color 160ms ease;
}

.button-secondary {
  border-color: var(--border-strong);
  background: transparent;
  color: var(--ink-900);
}

.button-light {
  background: #fff;
  color: var(--navy-900);
}

.button-disabled,
.button[aria-disabled="true"] {
  border-color: var(--border);
  background: #e8edf2;
  color: #5a6b7c;
  cursor: not-allowed;
}

.button-full {
  width: 100%;
}

.tool-hero,
.products-hero {
  padding: 30px 0 34px;
  background: var(--navy-900);
  color: #fff;
}

.tool-hero h1,
.products-hero h1 {
  font-size: clamp(2rem, 7vw, 3.1rem);
}

.back-link {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  margin-bottom: 14px;
  color: #c6d4e3;
  font-size: 0.88rem;
  font-weight: 650;
}

.tool-hero p:not(.eyebrow),
.products-hero p:not(.eyebrow) {
  max-width: 680px;
  margin: 14px 0 0;
  color: #c6d4e3;
}

.calculator-section {
  padding: 24px 0 36px;
}

.calculator-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
  align-items: start;
}

.calculator-card,
.formula-card,
.product-card {
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: var(--surface);
  box-shadow: var(--shadow);
}

.calculator-card {
  padding: 22px;
}

.calculator-card h2,
.formula-card h2 {
  margin: 0 0 6px;
  font-size: 1.25rem;
  line-height: 1.35;
}

.card-intro {
  margin: 0 0 22px;
  color: var(--ink-600);
  font-size: 0.9rem;
}

.form-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

.field {
  display: flex;
  min-width: 0;
  flex-direction: column;
  gap: 7px;
  color: var(--ink-900);
  font-size: 0.88rem;
  font-weight: 700;
}

.field input {
  width: 100%;
  min-width: 0;
  min-height: 48px;
  padding: 11px 13px;
  border: 1px solid var(--border-strong);
  border-radius: 9px;
  background: #fff;
  color: var(--ink-900);
  font-size: 16px;
  font-weight: 500;
  font-variant-numeric: tabular-nums;
}

.field input::placeholder {
  color: #718194;
  font-weight: 400;
}

.field input:focus {
  border-color: var(--blue-500);
  box-shadow: 0 0 0 3px rgba(33, 133, 229, 0.12);
}

.field-note,
.form-note {
  margin: 0;
  color: var(--ink-600);
  font-size: 0.8rem;
  font-weight: 400;
}

.form-note {
  margin-top: 12px;
  line-height: 1.55;
}

.mode-fieldset {
  min-width: 0;
  margin: 0 0 20px;
  padding: 0;
  border: 0;
}

.mode-fieldset legend {
  margin-bottom: 8px;
  color: var(--ink-900);
  font-size: 0.88rem;
  font-weight: 700;
}

.mode-control {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4px;
  padding: 4px;
  border-radius: 11px;
  background: #eaf0f6;
}

.mode-option {
  position: relative;
  min-width: 0;
  cursor: pointer;
}

.mode-option input {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
}

.mode-option span {
  display: flex;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  padding: 8px;
  border: 1px solid transparent;
  border-radius: 8px;
  color: var(--ink-600);
  font-size: 0.82rem;
  font-weight: 700;
  text-align: center;
}

.mode-option input:checked + span {
  border-color: var(--border);
  background: #fff;
  color: var(--navy-900);
  box-shadow: 0 2px 6px rgba(6, 21, 37, 0.08);
}

.mode-option input:focus-visible + span {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
}

.mode-panel .form-grid {
  margin-bottom: 18px;
}

.form-actions {
  margin-top: 20px;
}

.error-message {
  margin-top: 16px;
  padding: 11px 13px;
  border: 1px solid #efc2c7;
  border-radius: 9px;
  background: var(--error-bg);
  color: var(--error);
  font-size: 0.85rem;
  line-height: 1.5;
}

.results-panel {
  padding: 24px;
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: var(--radius-md);
  background: var(--navy-850);
  color: #fff;
}

.results-kicker {
  margin: 0 0 4px;
  color: var(--mint-400);
  font-size: 0.72rem;
  font-weight: 750;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.results-panel h2 {
  margin: 0 0 18px;
  font-size: 1.25rem;
}

.result-list {
  margin: 0;
}

.result-row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  padding: 15px 0;
  border-top: 1px solid rgba(255, 255, 255, 0.12);
}

.result-row dt {
  color: #c6d4e3;
  font-size: 0.88rem;
}

.result-row dd {
  margin: 0;
  color: #fff;
  font-size: 1.25rem;
  font-weight: 750;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.025em;
  text-align: right;
  overflow-wrap: anywhere;
}

.results-note {
  margin: 16px 0 0;
  color: #aebfd0;
  font-size: 0.78rem;
  line-height: 1.55;
}

.export-cta {
  margin-top: 14px;
  padding: 18px;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: var(--surface);
}

.export-cta-text {
  margin: 0 0 12px;
  color: var(--navy-850);
  font-size: 0.88rem;
  font-weight: 700;
}

.export-cta .button {
  font-size: 0.88rem;
}

.export-cta-note {
  margin: 10px 0 0;
  color: var(--ink-600);
  font-size: 0.76rem;
  line-height: 1.5;
  text-align: center;
}

/* 未计算前只露出一行低调的 workbook 链接。 */
.export-lowkey {
  margin: 14px 0 0;
  text-align: center;
}

.export-lowkey a {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  color: var(--blue-600);
  font-size: 0.82rem;
  font-weight: 650;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.export-cta-link {
  display: flex;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  color: var(--blue-600);
  font-size: 0.82rem;
  font-weight: 700;
}

.formula-card {
  margin-top: 18px;
  padding: 22px;
  box-shadow: none;
}

.formula-list {
  display: grid;
  gap: 10px;
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
}

.formula-list li {
  padding: 12px 14px;
  border-left: 3px solid var(--blue-500);
  border-radius: 0 8px 8px 0;
  background: var(--blue-100);
  color: var(--navy-850);
  font-size: 0.88rem;
  font-weight: 650;
  overflow-wrap: anywhere;
}

.formula-note {
  margin: 16px 0 0;
  color: var(--ink-600);
  font-size: 0.85rem;
}

.tier-list {
  display: grid;
  gap: 14px;
}

.tier-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  padding: 16px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: #f8fafc;
}

.tier-heading {
  display: flex;
  grid-column: 1 / -1;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.tier-name {
  color: var(--navy-850);
  font-size: 0.86rem;
  font-weight: 750;
}

.remove-tier {
  min-width: 64px;
  min-height: 44px;
  padding: 6px 8px;
  border: 0;
  background: transparent;
  color: var(--error);
  font-size: 0.8rem;
  font-weight: 700;
}

.remove-tier:disabled {
  color: #8795a4;
}

.add-tier {
  width: 100%;
  margin-top: 12px;
}

.products-section {
  padding: 28px 0 40px;
}

.product-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
}

.product-card {
  display: flex;
  flex-direction: column;
  padding: 26px;
}

.product-type {
  margin: 0 0 10px;
  color: var(--blue-600);
  font-size: 0.72rem;
  font-weight: 750;
  letter-spacing: 0.11em;
  text-transform: uppercase;
}

.product-card h2 {
  margin: 0;
  font-size: 1.4rem;
  line-height: 1.3;
  letter-spacing: -0.025em;
}

.product-price {
  margin: 18px 0;
  color: var(--navy-900);
  font-size: 2.4rem;
  font-weight: 780;
  line-height: 1;
  letter-spacing: -0.04em;
}

.sheet-count {
  display: inline-block;
  margin-left: 6px;
  padding: 5px 9px;
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  color: var(--navy-850);
  font-size: 0.74rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  vertical-align: middle;
}

.product-card > p.product-meta {
  margin: -8px 0 18px;
  color: var(--ink-700);
  font-size: 0.8rem;
  font-weight: 600;
}

.proof-strip {
  display: grid;
  gap: 8px;
  margin: 0 0 22px;
  padding: 14px 18px;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: var(--surface);
  list-style: none;
  color: var(--ink-700);
  font-size: 0.82rem;
}

.proof-strip li {
  display: flex;
  gap: 8px;
  align-items: baseline;
}

.proof-strip strong {
  color: var(--navy-850);
}

@media (min-width: 600px) {
  .proof-strip {
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
  }
}

.hero-upsell {
  margin: 14px 0 0;
  color: #c6d4e3;
  font-size: 0.86rem;
}

.hero-upsell a {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  color: #fff;
  font-weight: 700;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.search-status-line {
  margin: 10px 0 0;
}

.product-card > p:not(.product-type) {
  margin: 0 0 18px;
  color: var(--ink-600);
}

.product-features {
  margin: 0 0 24px;
  padding-left: 20px;
  color: var(--ink-700);
  font-size: 0.9rem;
}

.product-features li + li {
  margin-top: 8px;
}

.product-card .button {
  width: 100%;
  margin-top: auto;
}

.checkout-note {
  margin: 14px 0 0;
  color: var(--ink-600);
  font-size: 0.78rem;
  text-align: center;
}

.product-card > p.product-upgrade {
  padding: 12px 14px;
  border-radius: 9px;
  background: var(--mint-100);
  color: var(--navy-850);
  font-size: 0.84rem;
  line-height: 1.55;
}

.faq-section {
  margin-top: 36px;
  padding-top: 32px;
  border-top: 1px solid var(--border);
}

.faq-section .section-heading {
  align-items: flex-start;
}

.faq-section .section-heading h2 {
  margin: 0;
}

.faq-eyebrow {
  margin-bottom: 10px;
  border-color: rgba(18, 104, 195, 0.22);
  background: var(--blue-100);
  color: var(--blue-600);
}

.faq-list {
  display: grid;
  gap: 10px;
}

.faq-item {
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--surface);
}

.faq-item summary {
  min-height: 54px;
  padding: 15px 18px;
  color: var(--navy-850);
  font-size: 0.92rem;
  font-weight: 700;
  cursor: pointer;
}

.faq-item summary::marker {
  color: var(--blue-600);
}

.faq-item p {
  margin: 0;
  padding: 0 18px 18px;
  color: var(--ink-600);
  font-size: 0.88rem;
  line-height: 1.65;
}

.faq-item[open] {
  border-color: var(--border-strong);
}

.monetization-slot {
  margin-top: 20px;
  padding: 18px;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: #edf2f7;
}

.slot-label {
  margin: 0 0 6px;
  color: var(--ink-600);
  font-size: 0.66rem;
  font-weight: 750;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.slot-title {
  margin: 0;
  font-size: 1rem;
}

.slot-text {
  margin: 5px 0 0;
  color: var(--ink-600);
  font-size: 0.85rem;
}

.slot-link {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  margin-top: 8px;
  color: var(--blue-600);
  font-size: 0.85rem;
  font-weight: 700;
}

.site-footer {
  padding: 28px 0;
  background: var(--navy-950);
  color: #aebfd0;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.footer-brand {
  color: #fff;
  font-weight: 750;
}

.footer-text {
  margin: 4px 0 0;
  font-size: 0.82rem;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 18px;
}

.footer-links a {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  font-size: 0.84rem;
}

.footer-links a[aria-disabled="true"] {
  cursor: default;
}

.footer-contact-note {
  margin-left: 6px;
  color: #8fa3b6;
  font-size: 0.72rem;
}

.footer-meta {
  margin: 0;
  font-size: 0.76rem;
}

.noscript-message {
  margin-top: 16px;
  padding: 12px;
  border-radius: 8px;
  background: var(--error-bg);
  color: var(--error);
}

@media (hover: hover) {
  .tool-card:hover {
    border-color: #91b6da;
    box-shadow: 0 12px 26px rgba(6, 21, 37, 0.08);
  }

  .site-nav a:hover,
  .back-link:hover,
  .footer-links a:hover {
    color: #fff;
  }

  .button:not([aria-disabled="true"]):hover {
    background: #0c57a3;
  }

  .button-light:not([aria-disabled="true"]):hover {
    background: var(--blue-100);
  }

  .button-secondary:not([aria-disabled="true"]):hover {
    background: #eaf0f6;
  }
}

@media (min-width: 480px) {
  .site-nav .nav-calculators {
    display: inline-flex;
  }

  .brand-name {
    font-size: 1.06rem;
  }

  .site-nav {
    gap: 6px;
  }

  .product-strip-inner {
    padding: 28px;
  }
}

@media (min-width: 600px) {
  .container {
    width: min(calc(100% - 48px), 1120px);
  }

  .hero {
    padding: 56px 0;
  }

  .tool-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .section-heading {
    flex-direction: row;
    align-items: end;
    justify-content: space-between;
  }

  .product-strip-inner {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
  }

  .product-strip-inner .button {
    flex: 0 0 auto;
  }

  .form-grid-two {
    grid-template-columns: repeat(2, 1fr);
  }

  .product-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .footer-inner {
    flex-direction: row;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
  }

  .footer-meta {
    width: 100%;
  }
}

@media (min-width: 900px) {
  .hero {
    padding: 72px 0;
  }

  .section {
    padding: 48px 0;
  }

  .tool-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 18px;
  }

  .tool-card {
    min-height: 190px;
  }

  .product-strip {
    padding-bottom: 48px;
  }

  .tool-hero,
  .products-hero {
    padding: 38px 0 44px;
  }

  .calculator-section {
    padding: 34px 0 48px;
  }

  .calculator-grid {
    grid-template-columns: minmax(0, 1.25fr) minmax(300px, 0.75fr);
    gap: 24px;
  }

  .calculator-card,
  .results-panel,
  .formula-card {
    padding: 28px;
  }

  .results-panel {
    position: sticky;
    top: 20px;
  }

  .formula-card {
    margin-top: 24px;
  }

  .products-section {
    padding: 38px 0 52px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }
}