/* CSS Reset & Variables */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Green-Gray Color Scheme */
    --primary-text: #2D3A36;
    --secondary-text: #A8B0AB;
    --accent-color: #B5C0BA;
    --background-primary: #FAF9F6;
    --background-secondary: #F9F7F3;
    --background-warm: #F5F3EF;
    --border-subtle: #E8E6E2;
    --border-focus: #D4D2CE;
    
    /* Complementary accent colors */
    --accent-strong: #D85B47; /* Warm coral-red, complementary to green-gray */
    --accent-strong-hover: #C04C38;
    
    /* Spacing Scale */
    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 2rem;
    --space-lg: 4rem;
    --space-xl: 6rem;
    --space-xxl: 8rem;
    
    /* Typography Scale */
    --text-xs: 0.875rem;
    --text-sm: 1rem;
    --text-base: 1.125rem;
    --text-lg: 1.25rem;
    --text-xl: 1.5rem;
    --text-2xl: 2rem;
    --text-3xl: 2.5rem;
    --text-4xl: 3rem;
    
    /* Container */
    --container-max: 1000px;
    --container-padding: 5%;
}

/* Base Typography */
body {
    font-family: 'SF Pro Display', -apple-system, BlinkMacSystemFont, 'Inter', system-ui, sans-serif;
    font-size: var(--text-base);
    line-height: 1.8;
    color: var(--primary-text);
    background-color: var(--background-primary);
    font-weight: 400;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* SPA Styles */
.page-loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 400px;
    padding: var(--space-lg);
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border-subtle);
    border-top: 3px solid var(--accent-strong);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: var(--space-md);
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.page-error {
    text-align: center;
    padding: var(--space-lg);
    min-height: 400px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.page-error h2 {
    color: var(--accent-strong);
    margin-bottom: var(--space-md);
}

.page-error button {
    background: var(--accent-strong);
    color: white;
    border: none;
    padding: var(--space-sm) var(--space-md);
    border-radius: 8px;
    font-size: var(--text-sm);
    cursor: pointer;
    margin-top: var(--space-md);
    transition: background-color 0.2s ease;
}

.page-error button:hover {
    background: var(--accent-strong-hover);
}

/* Contact Page Styles */
.contact-hero {
    background: var(--background-secondary);
    padding: var(--space-xl) 0 var(--space-lg);
    margin-top: 80px;
    text-align: center;
}

.contact-hero h1 {
    font-size: var(--text-3xl);
    font-weight: 700;
    color: var(--primary-text);
    margin-bottom: var(--space-sm);
}

.contact-form-section {
    padding: var(--space-xl) 0;
}

.contact-form {
    max-width: 600px;
    margin: 0 auto;
}

.form-group {
    margin-bottom: var(--space-md);
}

.form-group label {
    display: block;
    margin-bottom: var(--space-xs);
    font-weight: 600;
    color: var(--primary-text);
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: var(--space-sm);
    border: 1px solid var(--border-subtle);
    border-radius: 8px;
    font-size: var(--text-sm);
    transition: border-color 0.2s ease;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--accent-strong);
}

.contact-submit-btn {
    background: var(--accent-strong);
    color: white;
    border: none;
    padding: var(--space-sm) var(--space-lg);
    border-radius: 8px;
    font-size: var(--text-sm);
    cursor: pointer;
    transition: background-color 0.2s ease;
    width: 100%;
}

.contact-submit-btn:hover {
    background: var(--accent-strong-hover);
}

.contact-submit-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.contact-status-message {
    margin-top: var(--space-md);
    padding: var(--space-sm);
    border-radius: 8px;
    text-align: center;
    display: none;
}

.contact-status-message.status-success {
    background: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.contact-status-message.status-error {
    background: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.contact-status-message.status-loading {
    background: var(--background-warm);
    color: var(--primary-text);
    border: 1px solid var(--border-subtle);
}

/* Not Found Page */
.not-found {
    text-align: center;
    padding: var(--space-xl) 0;
    margin-top: 80px;
    min-height: 400px;
    display: flex;
    align-items: center;
}

.not-found h1 {
    font-size: var(--text-3xl);
    color: var(--accent-strong);
    margin-bottom: var(--space-md);
}

.btn-primary {
    display: inline-block;
    background: var(--accent-strong);
    color: white;
    text-decoration: none;
    padding: var(--space-sm) var(--space-lg);
    border-radius: 8px;
    font-size: var(--text-sm);
    transition: background-color 0.2s ease;
    margin-top: var(--space-md);
}

.btn-primary:hover {
    background: var(--accent-strong-hover);
}

.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--container-padding);
}

/* Header - Lobsterr inspired minimal navigation */
.header {
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-subtle);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    transition: all 0.3s cubic-bezier(.165,.84,.44,1);
    height: 80px;
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 25px var(--container-padding);
    max-width: var(--container-max);
    margin: 0 auto;
    height: 100%;
}

.logo {
    font-size: var(--text-xl);
    font-weight: 600;
    color: var(--primary-text);
    text-decoration: none;
    letter-spacing: -0.02em;
}

.nav-links {
    display: flex;
    gap: var(--space-md);
    list-style: none;
}

.nav-links a {
    color: var(--secondary-text);
    text-decoration: none;
    font-weight: 500;
    font-size: var(--text-sm);
    position: relative;
    transition: color 0.3s ease;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0%;
    height: 1px;
    background: var(--primary-text);
    transition: width 0.3s cubic-bezier(.165,.84,.44,1);
}

.nav-links a:hover {
    color: var(--primary-text);
}

.nav-links a:hover::after,
.nav-links a.active::after {
    width: 100%;
}

.nav-links a.active {
    color: var(--primary-text);
}

/* Hero Section - Minimal and Intellectual */
.hero {
    padding: calc(80px + var(--space-xxl)) 0 var(--space-xl);
    text-align: center;
    background: var(--background-primary);
}

.hero-content {
    max-width: 700px;
    margin: 0 auto;
}

.hero h1 {
    font-size: clamp(var(--text-3xl), 5vw, var(--text-4xl));
    font-weight: 700;
    color: var(--primary-text);
    margin-bottom: var(--space-md);
    letter-spacing: -0.03em;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: var(--text-lg);
    color: var(--secondary-text);
    margin-bottom: var(--space-lg);
    line-height: 1.6;
    font-weight: 400;
}

/* Hero Newsletter Section */
.hero-newsletter {
    margin-top: var(--space-lg);
    max-width: 500px;
    margin-left: auto;
    margin-right: auto;
}

.newsletter-description {
    font-size: var(--text-base);
    color: var(--secondary-text);
    margin-bottom: var(--space-md);
    line-height: 1.6;
}

/* Hero Email Form */
.hero-email-form {
    display: flex;
    gap: var(--space-sm);
    margin-bottom: var(--space-sm);
}

.hero-email-input {
    flex: 1;
    padding: 14px 18px;
    border: 1px solid var(--border-subtle);
    border-radius: 10px;
    font-size: var(--text-base);
    background: var(--background-primary);
    transition: all 0.3s ease;
    font-family: inherit;
}

.hero-email-input:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(181, 192, 186, 0.1);
}

.hero-email-input::placeholder {
    color: var(--secondary-text);
    opacity: 0.7;
}

.hero-submit-btn {
    padding: 14px 28px;
    background: var(--accent-color);
    color: var(--primary-text);
    border: none;
    border-radius: 10px;
    font-size: var(--text-base);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    white-space: nowrap;
    font-family: inherit;
}

.hero-submit-btn:hover {
    background: #9FADA7;
    transform: translateY(-1px);
    box-shadow: 0 10px 30px rgba(181, 192, 186, 0.3);
}

.hero-submit-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

/* Hero Status Messages */
.hero-status-message {
    display: none;
    padding: var(--space-sm);
    border-radius: 8px;
    font-size: var(--text-sm);
    font-weight: 500;
    text-align: center;
}

/* Hero Stats - Lobsterr style metrics */
.hero-stats {
    display: flex;
    justify-content: center;
    gap: var(--space-lg);
    margin-top: var(--space-lg);
}

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

.stat-number {
    display: block;
    font-size: var(--text-2xl);
    font-weight: 700;
    color: var(--accent-color);
    line-height: 1;
    margin-bottom: var(--space-xs);
}

.stat-label {
    font-size: var(--text-xs);
    color: var(--secondary-text);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* Section Styling */
section {
    padding: var(--space-xl) 0;
}

section:nth-child(even) {
    background: var(--background-warm);
}

.section-header {
    text-align: center;
    margin-bottom: var(--space-lg);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.section-header h2 {
    font-size: var(--text-2xl);
    font-weight: 700;
    color: var(--primary-text);
    margin-bottom: var(--space-sm);
    letter-spacing: -0.02em;
    line-height: 1.3;
}

.section-header p {
    color: var(--secondary-text);
    font-size: var(--text-base);
    line-height: 1.6;
}

/* Features Section - Minimalist Grid */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--space-md);
    margin-top: var(--space-lg);
}

.feature-card {
    background: var(--background-primary);
    border: 1px solid var(--border-subtle);
    border-radius: 12px;
    padding: var(--space-md);
    text-align: left;
    transition: all 0.3s cubic-bezier(.165,.84,.44,1);
    position: relative;
    overflow: hidden;
}

.feature-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.1);
    border-color: var(--border-focus);
}

.feature-number {
    font-size: var(--text-xs);
    font-weight: 700;
    color: var(--accent-strong);
    margin-bottom: var(--space-sm);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

.feature-card h3 {
    font-size: var(--text-lg);
    font-weight: 600;
    color: var(--primary-text);
    margin-bottom: var(--space-sm);
    letter-spacing: -0.01em;
}

.feature-card p {
    color: var(--secondary-text);
    font-size: var(--text-sm);
    line-height: 1.6;
}

/* Past Issues Section */
.past-issues {
    background: var(--background-primary);
}

.issues-list {
    max-width: 700px;
    margin: 0 auto;
}

.issue-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-md) 0;
    border-bottom: 1px solid var(--border-subtle);
    transition: all 0.3s ease;
}

.issue-item:last-child {
    border-bottom: none;
}

.issue-item:hover {
    transform: translateX(4px);
    background: var(--background-warm);
    margin: 0 calc(-1 * var(--space-md));
    padding-left: var(--space-md);
    padding-right: var(--space-md);
    border-radius: 8px;
}

.issue-content {
    flex: 1;
}

.issue-title {
    font-size: var(--text-lg);
    font-weight: 600;
    color: var(--primary-text);
    margin-bottom: var(--space-xs);
    line-height: 1.4;
    letter-spacing: -0.01em;
}

.issue-date {
    font-size: var(--text-sm);
    color: var(--secondary-text);
    font-weight: 500;
}

.issue-link {
    color: var(--accent-strong);
    text-decoration: none;
    font-size: var(--text-sm);
    font-weight: 700;
    letter-spacing: 0.05em;
    transition: all 0.3s ease;
    white-space: nowrap;
    margin-left: var(--space-md);
    text-transform: uppercase;
}

.issue-link:hover {
    color: var(--accent-strong-hover);
    transform: translateX(6px);
}

/* Past Issues Loading States */
.loading-issues,
.error-issues,
.no-issues {
    text-align: center;
    padding: var(--space-lg);
    color: var(--secondary-text);
    font-size: var(--text-base);
}

.loading-issues {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
}

.error-issues {
    color: var(--accent-strong);
}

.issue-videos {
    font-size: var(--text-xs);
    color: var(--secondary-text);
    margin-top: var(--space-xs);
    font-weight: 500;
}

/* CTA Section */
.cta {
    background: var(--background-secondary);
    text-align: center;
}

.cta h2 {
    font-size: var(--text-2xl);
    font-weight: 700;
    color: var(--primary-text);
    margin-bottom: var(--space-sm);
    letter-spacing: -0.02em;
}

.cta p {
    color: var(--secondary-text);
    margin-bottom: var(--space-lg);
    font-size: var(--text-base);
}

/* Email Form */
.email-form {
    display: flex;
    gap: var(--space-sm);
    max-width: 400px;
    margin: 0 auto var(--space-md);
}

.email-input {
    flex: 1;
    padding: 12px 16px;
    border: 1px solid var(--border-subtle);
    border-radius: 8px;
    font-size: var(--text-sm);
    background: var(--background-primary);
    transition: all 0.3s ease;
}

.email-input:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(181, 192, 186, 0.1);
}

.submit-btn {
    padding: 12px 24px;
    background: var(--accent-color);
    color: var(--primary-text);
    border: none;
    border-radius: 8px;
    font-size: var(--text-sm);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    white-space: nowrap;
}

.submit-btn:hover {
    background: #9FADA7;
    transform: translateY(-1px);
}

.submit-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

/* Status Messages */
.status-message {
    display: none;
    padding: var(--space-sm);
    border-radius: 8px;
    font-size: var(--text-sm);
    font-weight: 500;
}

.status-success {
    background: #f0fdf4;
    color: #166534;
    border: 1px solid #bbf7d0;
}

.status-error {
    background: #fef2f2;
    color: #dc2626;
    border: 1px solid #fecaca;
}

/* About Section */
.about {
    background: var(--background-primary);
}

.about-content {
    max-width: 700px;
    margin: 0 auto;
    text-align: center;
}

.about h2 {
    font-size: var(--text-3xl);
    font-weight: 700;
    color: var(--primary-text);
    margin-bottom: var(--space-md);
    letter-spacing: -0.03em;
    line-height: 1.2;
}

.about-lead {
    font-size: var(--text-lg);
    color: var(--secondary-text);
    line-height: 1.7;
    margin-bottom: var(--space-lg);
}

/* About Metrics */
.about-metrics {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--space-md);
    margin-top: var(--space-lg);
}

.metric {
    text-align: center;
    padding: var(--space-md);
}

.metric-value {
    font-size: var(--text-lg);
    font-weight: 700;
    color: var(--primary-text);
    margin-bottom: var(--space-xs);
    letter-spacing: -0.01em;
}

.metric-label {
    font-size: var(--text-xs);
    color: var(--secondary-text);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* Footer */
.footer {
    background: var(--background-warm);
    border-top: 1px solid var(--border-subtle);
    padding: var(--space-lg) 0 var(--space-md);
}

.footer-content {
    text-align: center;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: var(--space-md);
    list-style: none;
    margin-bottom: var(--space-md);
}

.footer-links a {
    color: var(--secondary-text);
    text-decoration: none;
    font-size: var(--text-sm);
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: var(--primary-text);
}

.copyright {
    color: var(--secondary-text);
    font-size: var(--text-xs);
}

/* Mobile Hamburger Menu */
.hamburger-menu {
    display: none;
    position: fixed;
    top: 90px; /* headerの下に配置 */
    right: 20px;
    z-index: 1001;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-subtle);
    border-radius: 10px;
    width: 48px;
    height: 48px;
    cursor: pointer;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 4px;
    transition: all 0.3s ease;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
}

.hamburger-menu span {
    width: 24px;
    height: 2px;
    background: var(--primary-text);
    transition: all 0.3s ease;
}

.hamburger-menu:hover {
    background: rgba(255, 255, 255, 1);
    border-color: var(--border-focus);
    transform: translateY(-50%) scale(1.05);
    box-shadow: 0 6px 25px rgba(0, 0, 0, 0.2);
}


/* Letters Page Layout */
.letters-layout {
    display: grid;
    grid-template-columns: 350px 1fr;
    height: calc(100vh - 80px); /* 固定高さ */
    margin-top: 80px;
    gap: 0;
    position: relative;
    overflow: hidden; /* 全体のオーバーフローを制御 */
}

/* Sidebar Overlay */
.sidebar-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 999;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.sidebar-overlay.active {
    opacity: 1;
}

/* Letters Sidebar */
.letters-sidebar {
    background: var(--background-secondary);
    border-right: 1px solid var(--border-subtle);
    padding: var(--space-lg) var(--space-md);
    overflow-y: auto;
    position: relative;
}

.sidebar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--space-lg);
}

.sidebar-close {
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: none; /* PCビューでは非表示 */
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
    color: var(--secondary-text);
}

.sidebar-close:hover {
    background: var(--background-warm);
    color: var(--primary-text);
}

.sidebar-close span {
    font-size: 24px;
    line-height: 1;
}


.letters-sidebar h2 {
    font-size: var(--text-xl);
    font-weight: 700;
    color: var(--primary-text);
    margin-bottom: 0;
    letter-spacing: -0.02em;
}

/* Week List */
.week-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.week-item {
    padding: var(--space-md);
    border-radius: 12px;
    margin-bottom: var(--space-sm);
    cursor: pointer;
    transition: all 0.3s ease;
    border: 1px solid transparent;
}

.week-item:hover {
    background: var(--background-primary);
    border-color: var(--border-subtle);
    transform: translateX(4px);
}

.week-item.active {
    background: var(--background-primary);
    border-color: var(--accent-strong);
    box-shadow: 0 4px 20px rgba(216, 91, 71, 0.1);
}

.week-date {
    display: block;
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--primary-text);
    margin-bottom: var(--space-xs);
    line-height: 1.4;
}

.week-videos {
    font-size: var(--text-xs);
    color: var(--accent-strong);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* Loading and Error States */
.loading-item,
.error-item,
.no-letters {
    padding: var(--space-md);
    text-align: center;
    color: var(--secondary-text);
    font-size: var(--text-sm);
    font-style: italic;
}

.error-item {
    color: var(--accent-strong);
}

/* Letters Content */
.letters-content {
    background: var(--background-primary);
    position: relative;
    height: 100%; /* 親の高さを継承 */
    overflow: hidden; /* 親でのオーバーフローを制御 */
}

/* Letter Display Container */
.letter-display {
    width: 100%;
    height: 100%; /* 親の高さを継承 */
    background: #FAF9F6;
    overflow-y: auto; /* 縦スクロールを有効化 */
    -webkit-overflow-scrolling: touch;
    padding: 0;
    position: relative;
    z-index: 1; /* オーバーレイより下に配置 */
}

/* Loading and error states */
.loading-letter,
.error-letter,
.letter-fallback,
.no-letter-selected {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100%;
    text-align: center;
    color: var(--secondary-text);
    font-size: var(--text-base);
    background: var(--background-primary);
}

.error-letter {
    color: var(--accent-strong);
}

.no-letter-selected {
    color: var(--secondary-text);
    font-style: italic;
}

/* メール用のスタイルを完全に保持するため、追加のスタイルは最小限に */
.letter-display table {
    font-family: 'SF Pro Display', -apple-system, BlinkMacSystemFont, 'Inter', system-ui, sans-serif;
}

/* Mobile responsive adjustments */
.letter-display .mobile-padding {
    padding-left: 12px !important;
    padding-right: 12px !important;
    margin-top: 16px !important;
    margin-bottom: 0 !important;
}

.letter-display .mobile-text {
    font-size: 12px !important;
}

/* Thank You Page */
.thank-you {
    min-height: calc(100vh - 160px);
    padding: calc(80px + var(--space-xxl)) 0 var(--space-xxl);
    background: var(--background-primary);
    display: flex;
    align-items: center;
}

.thank-you-content {
    max-width: 600px;
    margin: 0 auto;
    text-align: center;
}

.thank-you-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto var(--space-lg);
    color: var(--accent-strong);
    background: rgba(216, 91, 71, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.thank-you-icon svg {
    width: 40px;
    height: 40px;
}

.thank-you h1 {
    font-size: var(--text-3xl);
    font-weight: 700;
    color: var(--primary-text);
    margin-bottom: var(--space-md);
    letter-spacing: -0.03em;
    line-height: 1.2;
}

.thank-you-message {
    font-size: var(--text-lg);
    color: var(--secondary-text);
    line-height: 1.7;
    margin-bottom: var(--space-xl);
}

/* Thank You Details */
.thank-you-details {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: var(--space-md);
    margin-bottom: var(--space-xl);
    padding: var(--space-lg);
    background: var(--background-secondary);
    border-radius: 16px;
    border: 1px solid var(--border-subtle);
}

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

.detail-item h3 {
    font-size: var(--text-sm);
    font-weight: 700;
    color: var(--accent-strong);
    margin-bottom: var(--space-xs);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.detail-item p {
    font-size: var(--text-base);
    color: var(--primary-text);
    font-weight: 600;
}

/* Thank You Actions */
.thank-you-actions {
    display: flex;
    gap: var(--space-md);
    justify-content: center;
    margin-bottom: var(--space-xl);
}

.primary-action {
    padding: 14px 28px;
    background: var(--accent-strong);
    color: var(--background-primary);
    text-decoration: none;
    border-radius: 10px;
    font-size: var(--text-base);
    font-weight: 600;
    transition: all 0.3s ease;
    border: 2px solid var(--accent-strong);
}

.primary-action:hover {
    background: var(--accent-strong-hover);
    border-color: var(--accent-strong-hover);
    transform: translateY(-1px);
    box-shadow: 0 10px 30px rgba(216, 91, 71, 0.3);
}

.secondary-action {
    padding: 14px 28px;
    background: transparent;
    color: var(--primary-text);
    text-decoration: none;
    border-radius: 10px;
    font-size: var(--text-base);
    font-weight: 600;
    transition: all 0.3s ease;
    border: 2px solid var(--border-subtle);
}

.secondary-action:hover {
    background: var(--background-secondary);
    border-color: var(--border-focus);
    transform: translateY(-1px);
}

/* Social Sharing */
.thank-you-social {
    padding-top: var(--space-lg);
    border-top: 1px solid var(--border-subtle);
}

.social-prompt {
    font-size: var(--text-base);
    color: var(--secondary-text);
    margin-bottom: var(--space-md);
}

.social-buttons {
    display: flex;
    gap: var(--space-sm);
    justify-content: center;
}

.social-btn {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    padding: 10px 20px;
    background: var(--background-secondary);
    color: var(--primary-text);
    text-decoration: none;
    border-radius: 8px;
    font-size: var(--text-sm);
    font-weight: 500;
    transition: all 0.3s ease;
    border: 1px solid var(--border-subtle);
}

.social-btn:hover {
    background: var(--background-warm);
    border-color: var(--border-focus);
    transform: translateY(-1px);
}

.social-btn svg {
    width: 16px;
    height: 16px;
}

/* Legal Pages Styling */
.legal-page {
    padding: calc(80px + var(--space-xl)) 0 var(--space-xl);
    background: var(--background-primary);
}

.legal-content {
    max-width: 800px;
    margin: 0 auto;
}

.legal-content h1 {
    font-size: var(--text-3xl);
    font-weight: 700;
    color: var(--primary-text);
    margin-bottom: var(--space-sm);
    letter-spacing: -0.03em;
    line-height: 1.2;
}

.last-updated {
    color: var(--secondary-text);
    font-size: var(--text-sm);
    margin-bottom: var(--space-xl);
    padding-bottom: var(--space-lg);
    border-bottom: 1px solid var(--border-subtle);
}

.legal-section {
    margin-bottom: var(--space-xl);
}

.legal-section h2 {
    font-size: var(--text-xl);
    font-weight: 700;
    color: var(--primary-text);
    margin-bottom: var(--space-md);
    letter-spacing: -0.02em;
}

.legal-section h3 {
    font-size: var(--text-lg);
    font-weight: 600;
    color: var(--primary-text);
    margin: var(--space-lg) 0 var(--space-sm) 0;
    letter-spacing: -0.01em;
}

.legal-section p {
    color: var(--primary-text);
    line-height: 1.8;
    margin-bottom: var(--space-md);
}

.legal-section ul {
    margin: var(--space-md) 0;
    padding-left: var(--space-lg);
}

.legal-section li {
    color: var(--primary-text);
    line-height: 1.7;
    margin-bottom: var(--space-xs);
}

.legal-section a {
    color: var(--accent-strong);
    text-decoration: none;
    transition: color 0.3s ease;
}

.legal-section a:hover {
    color: var(--accent-strong-hover);
    text-decoration: underline;
}

.legal-actions {
    margin-top: var(--space-xxl);
    padding-top: var(--space-lg);
    border-top: 1px solid var(--border-subtle);
    text-align: center;
}

.back-to-home {
    display: inline-block;
    padding: 12px 24px;
    background: var(--accent-color);
    color: var(--primary-text);
    text-decoration: none;
    border-radius: 8px;
    font-weight: 600;
    transition: all 0.3s ease;
    border: 1px solid var(--border-subtle);
}

.back-to-home:hover {
    background: var(--background-secondary);
    border-color: var(--border-focus);
    transform: translateY(-1px);
}

/* Contact Page Styling */
.contact-page {
    padding: calc(80px + var(--space-xl)) 0 var(--space-xl);
    background: var(--background-primary);
}

.contact-content {
    max-width: 1000px;
    margin: 0 auto;
}

.contact-header {
    text-align: center;
    margin-bottom: var(--space-xxl);
}

.contact-header h1 {
    font-size: var(--text-3xl);
    font-weight: 700;
    color: var(--primary-text);
    margin-bottom: var(--space-md);
    letter-spacing: -0.03em;
    line-height: 1.2;
}

.contact-subtitle {
    font-size: var(--text-lg);
    color: var(--secondary-text);
    line-height: 1.6;
}

/* Contact Methods Grid */
.contact-methods {
    margin-bottom: var(--space-xxl);
}

.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--space-md);
}

.contact-card {
    background: var(--background-secondary);
    border: 1px solid var(--border-subtle);
    border-radius: 12px;
    padding: var(--space-lg);
    text-align: center;
    transition: all 0.3s ease;
}

.contact-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 40px rgba(45, 58, 54, 0.1);
    border-color: var(--border-focus);
}

.contact-icon {
    width: 60px;
    height: 60px;
    margin: 0 auto var(--space-md);
    color: var(--accent-strong);
    background: rgba(216, 91, 71, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.contact-icon svg {
    width: 28px;
    height: 28px;
}

.contact-card h3 {
    font-size: var(--text-lg);
    font-weight: 600;
    color: var(--primary-text);
    margin-bottom: var(--space-sm);
    letter-spacing: -0.01em;
}

.contact-card p {
    color: var(--secondary-text);
    margin-bottom: var(--space-md);
    line-height: 1.6;
}

.contact-action {
    display: inline-block;
    color: var(--accent-strong);
    text-decoration: none;
    font-weight: 600;
    padding: 8px 16px;
    border-radius: 6px;
    transition: all 0.3s ease;
    background: rgba(216, 91, 71, 0.1);
}

.contact-action:hover {
    background: rgba(216, 91, 71, 0.2);
    transform: translateY(-1px);
}

/* Contact Form */
.contact-form-section {
    background: var(--background-secondary);
    border-radius: 16px;
    padding: var(--space-xl);
    margin-bottom: var(--space-xxl);
    border: 1px solid var(--border-subtle);
}

.contact-form-section h2 {
    font-size: var(--text-2xl);
    font-weight: 700;
    color: var(--primary-text);
    margin-bottom: var(--space-sm);
    letter-spacing: -0.02em;
}

.form-description {
    color: var(--secondary-text);
    margin-bottom: var(--space-lg);
    line-height: 1.6;
}

.contact-form {
    max-width: 600px;
}

.form-group {
    margin-bottom: var(--space-lg);
}

.form-group label {
    display: block;
    font-weight: 600;
    color: var(--primary-text);
    margin-bottom: var(--space-xs);
    font-size: var(--text-sm);
}

.required {
    color: var(--accent-strong);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border-subtle);
    border-radius: 8px;
    font-size: var(--text-base);
    background: var(--background-primary);
    transition: all 0.3s ease;
    font-family: inherit;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--accent-strong);
    box-shadow: 0 0 0 3px rgba(216, 91, 71, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

.form-actions {
    margin-top: var(--space-lg);
}

.contact-submit-btn {
    padding: 14px 28px;
    background: var(--accent-strong);
    color: var(--background-primary);
    border: none;
    border-radius: 8px;
    font-size: var(--text-base);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: inherit;
}

.contact-submit-btn:hover {
    background: var(--accent-strong-hover);
    transform: translateY(-1px);
    box-shadow: 0 10px 30px rgba(216, 91, 71, 0.3);
}

.contact-submit-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

.contact-status-message {
    display: none;
    margin-top: var(--space-md);
    padding: var(--space-sm);
    border-radius: 8px;
    font-size: var(--text-sm);
    font-weight: 500;
    border: 1px solid;
    text-align: center;
}

.contact-status-message.status-success {
    background: #d4edda;
    color: #155724;
    border-color: #c3e6cb;
}

.contact-status-message.status-error {
    background: #f8d7da;
    color: #721c24;
    border-color: #f5c6cb;
}

.contact-status-message.status-loading {
    background: #e2f3ff;
    color: #0c5460;
    border-color: #bee5eb;
}

.loading {
    display: inline-block;
    width: 14px;
    height: 14px;
    border: 2px solid transparent;
    border-top: 2px solid currentColor;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-right: 8px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* FAQ Section */
.contact-info h2 {
    font-size: var(--text-2xl);
    font-weight: 700;
    color: var(--primary-text);
    margin-bottom: var(--space-lg);
    letter-spacing: -0.02em;
}

.faq-list {
    display: grid;
    gap: var(--space-md);
}

.faq-item {
    background: var(--background-secondary);
    border: 1px solid var(--border-subtle);
    border-radius: 8px;
    padding: var(--space-md);
}

.faq-item h4 {
    font-size: var(--text-base);
    font-weight: 600;
    color: var(--primary-text);
    margin-bottom: var(--space-xs);
}

.faq-item p {
    color: var(--secondary-text);
    line-height: 1.6;
}

.faq-item a {
    color: var(--accent-strong);
    text-decoration: none;
}

.faq-item a:hover {
    text-decoration: underline;
}


/* Responsive Design */
@media (max-width: 768px) {
    /* スマホ用設定: 統一スクロールエリアを実現 */
    body.letters-page {
        overflow-y: auto; /* bodyレベルでの自然なスクロールを有効化 */
        height: auto; /* 高さ制限を解除 */
    }
    
    :root {
        --container-padding: 5%;
    }
    
    .nav {
        padding: 20px var(--container-padding);
    }
    
    .nav-links {
        gap: var(--space-sm);
    }
    
    .hero {
        padding: calc(80px + var(--space-lg)) 0 var(--space-lg);
    }
    
    .hero-stats {
        flex-direction: column;
        gap: var(--space-md);
        align-items: center;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
        gap: var(--space-sm);
    }
    
    .email-form {
        flex-direction: column;
        align-items: stretch;
    }
    
    .hero-email-form {
        flex-direction: column;
        gap: var(--space-sm);
    }
    
    .about-metrics {
        grid-template-columns: 1fr;
        gap: var(--space-sm);
    }
    
    .footer-links {
        flex-direction: column;
        gap: var(--space-sm);
    }
    
    .issue-item {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--space-sm);
    }
    
    .issue-item:hover {
        transform: none;
        margin: 0;
        padding: var(--space-md);
    }
    
    .issue-link {
        margin-left: 0;
        align-self: flex-end;
    }
    
    /* Mobile hamburger menu */
    .hamburger-menu {
        display: flex;
        top: 90px; /* headerの下に固定 */
        right: var(--container-padding);
        transform: none;
        transition: opacity 0.3s ease, visibility 0.3s ease;
    }
    
    .hamburger-menu.active {
        opacity: 0;
        visibility: hidden;
    }
    
    .hamburger-menu:hover {
        transform: scale(1.05);
    }
    
    /* Letters page responsive */
    .letters-layout {
        grid-template-columns: 1fr;
        margin-top: 80px;
        /* 高さ制限を完全に解除してfooterまで表示 */
        overflow: visible;
        position: relative;
    }
    
    .letters-sidebar {
        position: fixed;
        top: 0;
        left: -350px;
        width: 350px;
        height: 100vh;
        padding: var(--space-lg) var(--space-md);
        border-right: 1px solid var(--border-subtle);
        border-left: none;
        border-bottom: none;
        z-index: 1001; /* オーバーレイより上に配置 */
        transition: left 0.3s ease;
        overflow-y: auto;
    }
    
    .letters-sidebar.active {
        left: 0;
    }
    
    .sidebar-overlay {
        display: none; /* デフォルトは非表示 */
    }
    
    .sidebar-overlay.active {
        display: block; /* アクティブ時のみ表示 */
    }
    
    
    .letters-sidebar h2 {
        font-size: var(--text-lg);
    }
    
    .sidebar-close {
        display: flex; /* モバイルビューでは表示 */
    }
    
    .week-item {
        padding: var(--space-sm);
        margin-bottom: var(--space-xs);
    }
    
    .week-item:hover {
        transform: none;
    }
    
    .letters-content {
        grid-column: 1;
        width: 100%;
        /* 高さ制限を完全に解除してコンテンツに応じた自然な高さに */
        overflow: visible;
        position: relative;
    }
    
    .letter-display {
        width: 100%;
        /* レターコンテンツがない場合の最小高さのみ指定 */
        min-height: 60vh; /* 画面の60%程度を最小高さに */
        overflow: visible;
        position: relative;
        padding: 0;
        padding-bottom: calc(env(safe-area-inset-bottom) + 20px);
    }
    
    /* モバイル用のメール表示調整 */
    .letter-display .mobile-padding {
        padding-left: 12px !important;
        padding-right: 12px !important;
        margin-top: 16px !important;
        margin-bottom: 0 !important;
    }
    
    .letter-display .mobile-text {
        font-size: 12px !important;
    }
    
    /* レター内のiframeコンテンツが底部で隠れないように */
    .letter-display iframe {
        margin-bottom: calc(env(safe-area-inset-bottom) + 40px);
    }
    
    /* レターコンテンツ全体の余白調整 */
    .letter-display > * {
        margin-bottom: calc(env(safe-area-inset-bottom) + 20px);
    }
    
    /* 「レターを選択してください」状態での表示調整 */
    .no-letter-selected {
        display: flex;
        align-items: center;
        justify-content: center;
        min-height: 60vh; /* footerが見えるよう高さを調整 */
        text-align: center;
        padding: var(--space-lg);
        color: var(--secondary-text);
        font-style: italic;
    }
    
    /* Thank you page responsive */
    .thank-you-details {
        grid-template-columns: 1fr;
        gap: var(--space-sm);
        padding: var(--space-md);
    }
    
    .thank-you-actions {
        flex-direction: column;
        align-items: center;
    }
    
    .primary-action,
    .secondary-action {
        width: 100%;
        max-width: 250px;
        text-align: center;
    }
    
    .social-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .social-btn {
        width: 100%;
        max-width: 200px;
        justify-content: center;
    }
    
    /* Legal and contact pages responsive */
    .contact-grid {
        grid-template-columns: 1fr;
        gap: var(--space-sm);
    }
    
    .contact-form-section {
        padding: var(--space-md);
    }
    
    .legal-content,
    .contact-content {
        padding: 0 var(--space-sm);
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: var(--text-2xl);
    }
    
    .hero-subtitle {
        font-size: var(--text-base);
    }
    
    .stat-number {
        font-size: var(--text-xl);
    }
}

/* Unsubscribe Page Styles */
.unsubscribe-section {
    background: var(--background-primary);
    padding: var(--space-xxl) 0;
    min-height: 100vh;
    display: flex;
    align-items: center;
    margin-top: 80px;
}

.unsubscribe-content {
    max-width: 600px;
    margin: 0 auto;
    text-align: center;
    background: #FFFFFF;
    padding: var(--space-lg);
    border-radius: 16px;
    box-shadow: 0 10px 40px rgba(45, 58, 54, 0.08);
}

.unsubscribe-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto var(--space-lg);
    color: var(--accent-strong);
    background: rgba(216, 91, 71, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.unsubscribe-icon svg {
    width: 40px;
    height: 40px;
    stroke: currentColor;
    stroke-width: 2;
}

.unsubscribe-title {
    font-size: var(--text-3xl);
    font-weight: 700;
    color: var(--primary-text);
    margin-bottom: var(--space-md);
    letter-spacing: -0.03em;
}

.unsubscribe-description {
    font-size: var(--text-lg);
    color: var(--secondary-text);
    line-height: 1.7;
    margin-bottom: var(--space-lg);
}

.unsubscribe-form {
    max-width: 400px;
    margin: 0 auto var(--space-lg);
    text-align: left;
}

.form-group {
    margin-bottom: var(--space-md);
}

.form-label {
    display: block;
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--primary-text);
    margin-bottom: var(--space-xs);
}

.form-input,
.form-select {
    width: 100%;
    padding: 16px 20px;
    border: 2px solid var(--border-subtle);
    border-radius: 12px;
    font-size: var(--text-base);
    font-family: inherit;
    background: #FFFFFF;
    color: var(--primary-text);
    transition: all 0.3s ease;
}

.form-input:focus,
.form-select:focus {
    outline: none;
    border-color: var(--accent-strong);
    box-shadow: 0 0 0 3px rgba(216, 91, 71, 0.1);
}

.form-select {
    cursor: pointer;
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3e%3cpath stroke='%236b7280' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.5' d='m6 8 4 4 4-4'/%3e%3c/svg%3e");
    background-position: right 12px center;
    background-repeat: no-repeat;
    background-size: 16px;
    padding-right: 40px;
    appearance: none;
}

.unsubscribe-submit-btn {
    width: 100%;
    padding: 18px;
    background: var(--accent-strong);
    color: #FFFFFF;
    border: none;
    border-radius: 12px;
    font-size: var(--text-base);
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-bottom: var(--space-md);
}

.unsubscribe-submit-btn:hover:not(:disabled) {
    background: var(--accent-strong-hover);
    transform: translateY(-1px);
    box-shadow: 0 10px 30px rgba(216, 91, 71, 0.3);
}

.unsubscribe-submit-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}


.status-message {
    display: none;
    padding: 16px 20px;
    border-radius: 12px;
    font-size: var(--text-base);
    margin: var(--space-md) 0;
    text-align: center;
}

.status-message.success {
    background: rgba(34, 197, 94, 0.1);
    color: #059669;
    border: 1px solid rgba(34, 197, 94, 0.2);
}

.status-message.error {
    background: rgba(239, 68, 68, 0.1);
    color: #DC2626;
    border: 1px solid rgba(239, 68, 68, 0.2);
}

.unsubscribe-footer {
    text-align: center;
    color: var(--secondary-text);
    font-size: var(--text-sm);
    line-height: 1.6;
}

.unsubscribe-footer p {
    margin-bottom: var(--space-xs);
}

.unsubscribe-footer a {
    color: var(--accent-strong);
    text-decoration: none;
    font-weight: 500;
}

.unsubscribe-footer a:hover {
    text-decoration: underline;
}

/* Mobile Responsiveness for Unsubscribe Page */
@media (max-width: 768px) {
    .unsubscribe-section {
        padding: var(--space-lg) 0;
    }
    
    .unsubscribe-content {
        margin: 0 var(--space-sm);
        padding: var(--space-md);
    }
    
    .unsubscribe-title {
        font-size: var(--text-2xl);
    }
    
    .unsubscribe-description {
        font-size: var(--text-base);
    }
}

.past-issues {
    background-color: var(--background-secondary);
}

.naming {
    background-color: var(--background-warm);
    padding: var(--space-xl) 0;
}

.naming-content {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 var(--space-md);
}

.naming-content p {
    margin-bottom: var(--space-md);
    font-size: var(--text-base);
    line-height: 1.8;
    color: var(--primary-text);
}

.naming-content p:last-child {
    margin-bottom: 0;
}

@media (max-width: 768px) {
    .naming {
        padding: var(--space-lg) 0;
    }
    
    .naming-content {
        padding: 0 var(--space-sm);
    }
    
    .naming-content p {
        font-size: var(--text-sm);
    }
}