/* ===== Reset & Base ===== */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --color-primary: #1a6b4a;
    --color-primary-light: #e8f5ee;
    --color-primary-hover: #145839;
    --color-accent: #d4a843;
    --color-bg: #f7f8fa;
    --color-surface: #ffffff;
    --color-text: #2c3e50;
    --color-text-muted: #6b7b8d;
    --color-border: #e2e6ea;
    --color-footer-bg: #2c3e50;
    --color-footer-text: #cfd8dc;
    --shadow-card: 0 2px 8px rgba(0, 0, 0, 0.06);
    --shadow-card-hover: 0 6px 20px rgba(0, 0, 0, 0.1);
    --radius: 10px;
    --max-width: 1080px;
    --transition: 0.25s ease;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Noto Sans JP', 'Hiragino Kaku Gothic ProN', 'Yu Gothic', sans-serif;
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.8;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    -webkit-font-smoothing: antialiased;
}

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

/* ===== Header ===== */
.header {
    background: linear-gradient(135deg, var(--color-primary) 0%, #1e7e56 100%);
    color: #fff;
    position: sticky;
    top: 0;
    padding: 0;
    z-index: 100;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.12);
}

.header__inner {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 14px 24px;
    display: flex;
    align-items: center;
    gap: 14px;
}

.header__inner--index {
    padding: 18px 24px;
}

.header__icon {
    font-size: 24px;
    flex-shrink: 0;
}

.header__inner--index .header__icon {
    font-size: 28px;
}

.header__home {
    display: flex;
    align-items: center;
    gap: 10px;
    color: #fff;
    transition: opacity var(--transition);
}

.header__home:hover {
    opacity: 0.85;
}

.header__title {
    font-size: 18px;
    font-weight: 700;
}

.header__inner--index .header__title {
    font-size: 20px;
    letter-spacing: 0.02em;
}

.header__subtitle {
    font-size: 12px;
    opacity: 0.85;
    font-weight: 400;
    display: block;
    margin-top: 2px;
    letter-spacing: 0.04em;
}

/* ===== Sub-navigation ===== */
.subnav {
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.subnav__inner {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    gap: 0;
}

.subnav__link {
    padding: 12px 18px;
    font-size: 13px;
    font-weight: 500;
    color: var(--color-text-muted);
    white-space: nowrap;
    border-bottom: 3px solid transparent;
    transition: color var(--transition), border-color var(--transition);
}

.subnav__link:hover {
    color: var(--color-primary);
}

.subnav__link--active {
    color: var(--color-primary);
    border-bottom-color: var(--color-primary);
    font-weight: 700;
}

/* ===== Breadcrumb ===== */
.breadcrumb {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 14px 24px 0;
    font-size: 12px;
    color: var(--color-text-muted);
    width: 100%;
}

.breadcrumb a {
    color: var(--color-primary);
    text-decoration: underline;
}

.breadcrumb a:hover {
    text-decoration: none;
}

/* ===== Main Content ===== */
.main {
    flex: 1;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 20px 24px 56px;
    width: 100%;
}

.page-title {
    font-size: 26px;
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: 8px;
    line-height: 1.4;
}

.page-subtitle {
    font-size: 14px;
    color: var(--color-text-muted);
    margin-bottom: 28px;
}

/* ===== Tool Card ===== */
.tool-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    box-shadow: var(--shadow-card);
    padding: 32px 28px;
    margin-bottom: 32px;
}

.tool-card__heading {
    font-size: 18px;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: 2px solid var(--color-primary-light);
}

/* ===== Form Controls ===== */
.form-row {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    align-items: flex-end;
    margin-bottom: 16px;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.form-group label {
    font-size: 13px;
    font-weight: 500;
    color: var(--color-text-muted);
}

.form-group select,
.form-group input[type="number"],
.form-group input[type="text"],
.form-group input[type="email"],
.form-group textarea {
    padding: 10px 14px;
    border: 1px solid var(--color-border);
    border-radius: 6px;
    font-size: 15px;
    font-family: inherit;
    background: var(--color-bg);
    color: var(--color-text);
    transition: border-color var(--transition);
    min-width: 160px;
}

.form-group select:focus,
.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(26, 107, 74, 0.12);
}

.form-group-row {
    display: flex;
    gap: 8px;
    align-items: center;
}

.reset-btn {
    padding: 10px 14px;
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: 6px;
    font-size: 14px;
    cursor: pointer;
    transition: all var(--transition);
    color: var(--color-text-muted);
    font-family: inherit;
    white-space: nowrap;
}

.reset-btn:hover {
    background: #e2e6ea;
    color: var(--color-text);
}

.checkbox-group {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 0;
}

.checkbox-group input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: var(--color-primary);
    cursor: pointer;
}

.checkbox-group label {
    font-size: 14px;
    cursor: pointer;
    color: var(--color-text);
}

/* ===== Result Display ===== */
.result-box {
    background: var(--color-primary-light);
    border: 1px solid #c8e6d5;
    border-radius: 8px;
    padding: 20px 24px;
    margin-top: 20px;
    display: none;
}

.result-box.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

.result-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 16px;
}

.result-item {
    text-align: center;
}

.result-item__label {
    font-size: 12px;
    color: var(--color-text-muted);
    margin-bottom: 4px;
}

.result-item__value {
    font-size: 28px;
    font-weight: 700;
    color: var(--color-primary);
    line-height: 1.3;
}

.result-item__sub {
    font-size: 13px;
    color: var(--color-text-muted);
    margin-top: 2px;
}

.scroll-to-table-btn {
    display: inline-block;
    margin-top: 20px;
    padding: 10px 24px;
    background: #fff;
    border: 1px solid var(--color-primary);
    color: var(--color-primary);
    border-radius: 20px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition);
    text-align: center;
    font-family: inherit;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.scroll-to-table-btn:hover {
    background: var(--color-primary-light);
    transform: translateY(-1px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.08);
}

/* ===== Table ===== */
.table-section {
    margin-bottom: 32px;
}

.table-section__heading {
    font-size: 18px;
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: 16px;
    padding-left: 14px;
    border-left: 4px solid var(--color-primary);
}

.table-wrapper {
    overflow-x: auto;
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    box-shadow: var(--shadow-card);
}

.age-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 14px;
    background: var(--color-surface);
}

.age-table thead {
    background: var(--color-primary);
    color: #fff;
}

.age-table th {
    padding: 12px 14px;
    font-weight: 500;
    font-size: 13px;
    white-space: nowrap;
    text-align: center;
    position: sticky;
    top: 0;
}

.age-table td {
    padding: 10px 14px;
    text-align: center;
    border-bottom: 1px solid var(--color-border);
    white-space: nowrap;
}

.age-table tbody tr:nth-child(even) {
    background: #f9fbfa;
}

.age-table tbody tr:hover {
    background: var(--color-primary-light);
}

.age-table tbody tr.highlight {
    background: #fff3cd;
    font-weight: 700;
}

.age-table tbody tr.highlight.pulse {
    animation: pulseHighlight 0.8s ease-in-out 2;
}

@keyframes pulseHighlight {
    0% {
        background-color: #fff3cd;
    }

    50% {
        background-color: #ffe680;
    }

    100% {
        background-color: #fff3cd;
    }
}

.era-reiwa {
    color: var(--color-primary);
    font-weight: 500;
}

.era-heisei {
    color: #2e7d9c;
    font-weight: 500;
}

.era-showa {
    color: #8b6914;
    font-weight: 500;
}

.era-taisho {
    color: #7b5ea7;
    font-weight: 500;
}

.era-meiji {
    color: #b85450;
    font-weight: 500;
}

/* ===== Article ===== */
.article {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    box-shadow: var(--shadow-card);
    padding: 36px 32px;
    margin-bottom: 32px;
}

.article h2 {
    font-size: 22px;
    font-weight: 700;
    color: var(--color-text);
    margin: 36px 0 16px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--color-primary-light);
}

.article h2:first-child {
    margin-top: 0;
}

.article h3 {
    font-size: 17px;
    font-weight: 700;
    color: var(--color-primary);
    margin: 24px 0 10px;
    padding-left: 12px;
    border-left: 3px solid var(--color-accent);
}

.article p {
    font-size: 15px;
    line-height: 2;
    margin-bottom: 16px;
    color: var(--color-text);
}

.article ul,
.article ol {
    margin: 0 0 16px 24px;
    font-size: 15px;
    line-height: 2;
}

.article .tip-box,
.note {
    background: #fffce8;
    border-left: 4px solid var(--color-accent);
    padding: 16px 20px;
    border-radius: 0 8px 8px 0;
    margin: 20px 0;
    font-size: 14px;
}

.article .tip-box strong,
.note strong {
    color: var(--color-accent);
}

/* ===== Ad Placeholder ===== */
.ad-slot {
    text-align: center;
    padding: 20px;
    margin: 28px 0;
    color: var(--color-text-muted);
    font-size: 12px;
}

/* ===== Footer ===== */
.footer {
    background: var(--color-footer-bg);
    color: var(--color-footer-text);
    font-size: 13px;
}

.footer__inner {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 32px 24px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
}

.footer__nav {
    display: flex;
    gap: 24px;
    flex-wrap: wrap;
    justify-content: center;
}

.footer__nav a {
    color: var(--color-footer-text);
    transition: color var(--transition);
    font-size: 13px;
    text-decoration: none;
}

.footer__nav a:hover {
    color: #fff;
}

.footer__copy {
    opacity: 0.7;
    font-size: 12px;
}

/* ===== Animations ===== */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ===== Responsive ===== */
@media (max-width: 640px) {
    .header__inner {
        padding: 12px 16px;
    }

    .header__inner--index {
        padding: 14px 16px;
    }

    .header__title {
        font-size: 16px;
    }

    .header__inner--index .header__title {
        font-size: 17px;
    }

    .header__subtitle {
        font-size: 11px;
    }

    .subnav__inner {
        padding: 0 12px;
    }

    .subnav__link {
        padding: 10px 12px;
        font-size: 12px;
    }

    .main {
        padding: 16px 16px 40px;
    }

    .page-title {
        font-size: 20px;
    }

    .tool-card {
        padding: 22px 16px;
    }

    .form-row {
        flex-direction: column;
    }

    .form-group select,
    .form-group input[type="number"],
    .form-group input[type="text"],
    .form-group input[type="email"],
    .form-group textarea {
        width: 100%;
        min-width: unset;
    }

    .result-item__value {
        font-size: 22px;
    }

    .article {
        padding: 24px 18px;
    }

    .article h2 {
        font-size: 18px;
    }

    .article h3 {
        font-size: 15px;
    }

    .age-table {
        font-size: 12px;
    }

    .age-table th,
    .age-table td {
        padding: 8px 8px;
    }

    .footer__nav {
        gap: 16px;
    }
}
/* Quick Links inside Quick Use */
.quick-links {
    margin-top: 16px;
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    align-items: center;
    justify-content: center;
}
.quick-links p {
    color: var(--color-text-muted);
    font-size: 0.9rem;
    margin: 0;
    width: 100%;
    text-align: center;
    margin-bottom: 4px;
}
.quick-links a {
    color: var(--color-primary);
    text-decoration: none;
    font-size: 0.95rem;
    padding: 4px 8px;
}
.quick-links a:hover {
    text-decoration: underline;
}
@media (max-width: 640px) {
    .quick-links {
        flex-direction: column;
        align-items: center;
    }
}

/* Back to Top Button */
#back-to-top {
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--color-primary);
  color: #fff;
  border: none;
  font-size: 1.4rem;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s, visibility 0.3s, transform 0.3s;
  z-index: 1000;
  box-shadow: 0 2px 8px rgba(0,0,0,0.15);
  display: flex;
  align-items: center;
  justify-content: center;
}
#back-to-top.visible {
  opacity: 1;
  visibility: visible;
}
#back-to-top:hover {
  background: var(--color-primary-hover);
  transform: translateY(-4px);
}

/* Mobile Sub-Nav Scroll Mask */
@media (max-width: 640px) {
  .sub-nav {
    position: relative;
  }
  .sub-nav::after {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 40px;
    height: 100%;
    background: linear-gradient(to right, transparent, var(--color-bg, #ffffff));
    pointer-events: none;
    z-index: 2;
    transition: opacity 0.3s;
  }
  .sub-nav.scrolled-end::after {
    opacity: 0;
    visibility: hidden;
  }
}

/* Copy Button */
.btn-copy {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--color-primary);
    color: var(--color-primary);
    background: transparent;
    border-radius: 6px;
    padding: 8px 16px;
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: background var(--transition), color var(--transition);
    margin: 16px auto 0;
    max-width: max-content;
}
.btn-copy:hover {
    background: var(--color-primary-light);
}
.btn-copy-wrapper {
    text-align: center;
}

/* ===== Dark Mode Variables ===== */
[data-theme="dark"] {
    --color-primary: #2ecc71;
    --color-primary-light: #1a3a2a;
    --color-primary-hover: #27ae60;
    --color-bg: #1a1a2e;
    --color-surface: #16213e;
    --color-text: #e0e0e0;
    --color-text-muted: #8899aa;
    --color-border: #2a2a4a;
    --color-footer-bg: #0f0f23;
    --color-footer-text: #8899aa;
    --color-accent: #f0c040;
    --shadow-card: 0 2px 12px rgba(0, 0, 0, 0.3);
    --shadow-card-hover: 0 8px 24px rgba(0, 0, 0, 0.4);
}

/* ===== Theme Toggle Button ===== */
.theme-toggle {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: rgba(255,255,255,0.15);
    border: 1px solid rgba(255,255,255,0.25);
    cursor: pointer;
    font-size: 1.2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s;
    margin-left: auto;
    flex-shrink: 0;
    line-height: 1;
    padding: 0;
}
.theme-toggle:hover {
    transform: rotate(15deg);
    background: rgba(255,255,255,0.25);
}

/* ===== Scroll Reveal Animations ===== */
.reveal {
    opacity: 0;
    transform: translateY(40px);
    transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}
.reveal.revealed {
    opacity: 1;
    transform: translateY(0);
}

/* ===== Card Icon Bounce ===== */
@keyframes iconBounce {
    0%   { transform: translateY(0); }
    30%  { transform: translateY(-4px); }
    50%  { transform: translateY(0); }
    70%  { transform: translateY(-2px); }
    100% { transform: translateY(0); }
}

/* ===== Dark Mode Adaptations ===== */
[data-theme="dark"] .subnav {
    background: var(--color-surface);
}

[data-theme="dark"] .age-table tbody tr:nth-child(even),
[data-theme="dark"] .ref-table tbody tr:nth-child(even),
[data-theme="dark"] .tl-table tbody tr:nth-child(even) {
    background: rgba(255,255,255,0.03);
}

[data-theme="dark"] .age-table tbody tr:hover,
[data-theme="dark"] .ref-table tbody tr:hover,
[data-theme="dark"] .tl-table tbody tr:hover {
    background: rgba(46,204,113,0.08);
}

[data-theme="dark"] .tool-card {
    background: var(--color-surface);
    border-color: var(--color-border);
}

[data-theme="dark"] .btn-copy {
    border-color: var(--color-primary);
    color: var(--color-primary);
}
[data-theme="dark"] .btn-copy:hover {
    background: var(--color-primary-light);
}

[data-theme="dark"] #back-to-top {
    box-shadow: 0 2px 8px rgba(0,0,0,0.4);
}

[data-theme="dark"] .tip-box {
    background: var(--color-surface);
    border-color: var(--color-border);
}

[data-theme="dark"] .mini-card {
    background: var(--color-surface);
    border-color: var(--color-border);
}

[data-theme="dark"] .info-box {
    background: var(--color-surface);
    border-color: var(--color-border);
}

[data-theme="dark"] .year-banner {
    background: var(--color-surface);
    border-color: var(--color-border);
}

[data-theme="dark"] select,
[data-theme="dark"] input[type="number"],
[data-theme="dark"] input[type="text"] {
    background: var(--color-surface);
    color: var(--color-text);
    border-color: var(--color-border);
}

[data-theme="dark"] .gender-tab {
    background: var(--color-surface);
    color: var(--color-text);
    border-color: var(--color-border);
}

[data-theme="dark"] .result-box {
    background: var(--color-surface);
    border-color: var(--color-border);
}

[data-theme="dark"] .hayaumare-note {
    background: var(--color-surface);
    border-color: var(--color-border);
}

[data-theme="dark"] .article {
    background: var(--color-surface);
}