/* ===== CSS Variables - Apple-inspired palette ===== */
:root {
    --bg-primary: #fbfbfd;
    --bg-secondary: #ffffff;
    --bg-tertiary: #f5f5f7;
    --text-primary: #1d1d1f;
    --text-secondary: #6e6e73;
    --text-tertiary: #86868b;
    --accent: #0071e3;
    --accent-hover: #0077ed;
    --border-color: #d2d2d7;
    --card-shadow: 0 4px 24px rgba(0, 0, 0, 0.04);
    --card-shadow-hover: 0 8px 40px rgba(0, 0, 0, 0.08);
    --radius-lg: 20px;
    --radius-md: 12px;
    --radius-sm: 8px;
    --transition: 0.4s cubic-bezier(0.25, 0.1, 0.25, 1);
    --max-width: 1080px;
    --font-stack: -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'SF Pro Text',
        'Helvetica Neue', 'Helvetica', 'Arial', sans-serif;
}

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

html {
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-stack);
    font-size: 17px;
    line-height: 1.5;
    letter-spacing: -0.022em;
    color: var(--text-primary);
    background-color: var(--bg-primary);
}

a {
    color: var(--accent);
    text-decoration: none;
    transition: color var(--transition);
}

a:hover {
    text-decoration: underline;
    text-underline-offset: 3px;
}

/* ===== Container ===== */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
}

@media (min-width: 1068px) {
    .container {
        padding: 0 40px;
    }
}

/* ===== Header - Frosted Glass Navbar ===== */
header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(251, 251, 253, 0.8);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    border-bottom: 1px solid var(--border-color);
}

header .container {
    display: flex;
    align-items: center;
    height: 52px;
}

header h1 {
    font-size: 21px;
    font-weight: 600;
    letter-spacing: -0.01em;
    color: var(--text-primary);
}

header h1 a {
    color: inherit;
    text-decoration: none;
}

header h1 a:hover {
    color: inherit;
    text-decoration: none;
}

/* ===== Hero Section ===== */
.hero {
    padding: 80px 0 60px;
    text-align: center;
}

.hero-title {
    font-size: 56px;
    font-weight: 700;
    letter-spacing: -0.04em;
    line-height: 1.07;
    color: var(--text-primary);
    margin-bottom: 16px;
}

.hero-subtitle {
    font-size: 21px;
    font-weight: 400;
    color: var(--text-secondary);
    line-height: 1.38;
    max-width: 600px;
    margin: 0 auto;
}

.hero-subtitle-en {
    font-size: 17px;
    color: var(--text-tertiary);
    margin-top: 8px;
}

/* ===== Main Content ===== */
main {
    padding: 0 0 3rem;
}

section {
    margin-bottom: 80px;
}

section h2 {
    font-size: 32px;
    font-weight: 700;
    letter-spacing: -0.03em;
    color: var(--text-primary);
    margin-bottom: 8px;
    border-bottom: none;
    padding-bottom: 0;
}

.section-subtitle {
    font-size: 17px;
    color: var(--text-secondary);
    margin-bottom: 32px;
}

/* ===== Reports Grid ===== */
.reports-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 24px;
}

.report-card {
    background: var(--bg-secondary);
    border: none;
    border-radius: var(--radius-lg);
    padding: 32px;
    box-shadow: var(--card-shadow);
    cursor: pointer;
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

.report-card.visible {
    opacity: 1;
    transform: translateY(0);
}

.report-card:hover {
    box-shadow: var(--card-shadow-hover);
    transform: translateY(-2px);
}

.report-card.visible:hover {
    transform: translateY(-2px);
}

.report-date {
    font-size: 28px;
    font-weight: 700;
    letter-spacing: -0.025em;
    color: var(--text-primary);
    margin-bottom: 8px;
    line-height: 1.15;
}

.report-stats {
    display: flex;
    gap: 16px;
    margin: 16px 0;
    font-size: 14px;
    color: var(--text-secondary);
}

.stat-item {
    display: flex;
    align-items: center;
    gap: 6px;
}

.report-link {
    display: inline-block;
    margin-top: 20px;
    padding: 0;
    background: none;
    color: var(--accent);
    text-decoration: none;
    font-size: 17px;
    font-weight: 400;
    transition: color var(--transition);
}

.report-link::after {
    content: ' \203A';
    display: inline-block;
    transition: transform var(--transition);
}

.report-link:hover {
    color: var(--accent-hover);
    text-decoration: underline;
    text-underline-offset: 3px;
}

.report-link:hover::after {
    transform: translateX(3px);
}

/* ===== Report Detail Page ===== */
.breadcrumb {
    margin-bottom: 40px;
    padding-top: 32px;
}

.breadcrumb a {
    color: var(--accent);
    text-decoration: none;
    font-size: 17px;
}

.breadcrumb a:hover {
    text-decoration: underline;
    text-underline-offset: 3px;
}

.report-detail {
    background: var(--bg-secondary);
    padding: 48px 56px;
    border-radius: var(--radius-lg);
    box-shadow: var(--card-shadow);
    max-width: 800px;
    margin: 0 auto;
}

.report-detail h1 {
    font-size: 40px;
    font-weight: 700;
    letter-spacing: -0.03em;
    line-height: 1.1;
    margin-bottom: 24px;
    color: var(--text-primary);
}

.report-detail h2 {
    font-size: 28px;
    font-weight: 700;
    letter-spacing: -0.025em;
    margin-top: 48px;
    margin-bottom: 16px;
    border-bottom: none;
    padding-bottom: 0;
    color: var(--text-primary);
}

.report-detail h3 {
    font-size: 21px;
    font-weight: 600;
    letter-spacing: -0.01em;
    margin-top: 32px;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.report-detail p {
    margin-bottom: 16px;
    line-height: 1.65;
    font-size: 17px;
    color: var(--text-primary);
}

.report-detail ul,
.report-detail ol {
    margin-left: 24px;
    margin-bottom: 16px;
}

.report-detail li {
    margin-bottom: 8px;
    line-height: 1.65;
}

.report-detail a {
    color: var(--accent);
    text-decoration: none;
    transition: color var(--transition);
}

.report-detail a:hover {
    text-decoration: underline;
    text-underline-offset: 3px;
}

.report-detail table {
    width: 100%;
    border-collapse: collapse;
    margin: 32px 0;
    font-size: 15px;
    overflow-x: auto;
    display: block;
}

.report-detail th,
.report-detail td {
    padding: 12px 16px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.report-detail th {
    background: transparent;
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 12px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.report-detail blockquote {
    border-left: 3px solid var(--border-color);
    padding-left: 24px;
    margin: 32px 0;
    font-style: normal;
    color: var(--text-secondary);
    font-size: 17px;
}

.report-detail hr {
    border: none;
    border-top: 1px solid var(--border-color);
    margin: 48px 0;
}

/* ===== About Section ===== */
#about {
    background: var(--bg-tertiary);
    border-radius: var(--radius-lg);
    padding: 48px;
}

#about h2 {
    margin-bottom: 8px;
}

#about .section-subtitle {
    margin-bottom: 24px;
}

#about p {
    margin-bottom: 16px;
    line-height: 1.65;
    font-size: 17px;
    color: var(--text-secondary);
}

#about ul {
    list-style: none;
    padding-left: 0;
    margin-top: 24px;
}

#about li {
    padding: 12px 0;
    border-bottom: 1px solid var(--border-color);
    font-size: 15px;
    color: var(--text-secondary);
}

#about li:last-child {
    border-bottom: none;
}

.source-link {
    margin-top: 24px;
    font-size: 14px;
    color: var(--text-tertiary);
}

.source-link a {
    color: var(--accent);
    text-decoration: none;
}

.source-link a:hover {
    text-decoration: underline;
    text-underline-offset: 3px;
}

/* ===== Loading & Error States ===== */
.loading {
    text-align: center;
    padding: 80px 24px;
    color: var(--text-tertiary);
    font-size: 17px;
}

.error {
    background-color: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 24px;
    border-radius: var(--radius-md);
    margin: 32px 0;
}

/* ===== Footer ===== */
footer {
    background-color: var(--bg-tertiary);
    color: var(--text-tertiary);
    padding: 24px 0;
    text-align: center;
    font-size: 12px;
    border-top: 1px solid var(--border-color);
}

/* ===== Responsive Design ===== */
@media (max-width: 1068px) {
    .hero-title {
        font-size: 44px;
    }

    .report-detail {
        padding: 40px;
    }
}

@media (max-width: 768px) {
    header .container {
        height: 48px;
    }

    header h1 {
        font-size: 18px;
    }

    .hero {
        padding: 60px 0 40px;
    }

    .hero-title {
        font-size: 36px;
    }

    .hero-subtitle {
        font-size: 19px;
    }

    section {
        margin-bottom: 60px;
    }

    section h2 {
        font-size: 24px;
    }

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

    .report-card {
        padding: 24px;
    }

    .report-date {
        font-size: 22px;
    }

    .report-detail {
        padding: 24px 20px;
        border-radius: var(--radius-md);
    }

    .report-detail h1 {
        font-size: 28px;
    }

    .report-detail h2 {
        font-size: 22px;
        margin-top: 32px;
    }

    #about {
        padding: 32px 24px;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 28px;
    }

    .hero-subtitle {
        font-size: 17px;
    }

    .report-date {
        font-size: 20px;
    }

    .report-detail h1 {
        font-size: 24px;
    }
}