/* ========================================
   Base Layout & Common Styles
   ======================================== */

/* ========================================
   1. CSS Custom Properties (Variables)
   ======================================== */
:root {
    /* Brand Colors */
    --brand-blue: #1f3c88;
    --brand-black: #101820;
    --brand-yellow: #f2a104;

    /* Text Colors */
    --text-light: #ffffff;
    --text-muted: rgba(255, 255, 255, 0.7);

    /* Background Colors */
    --bg-page: #ffffff;
    --bg-section: #f5f8ff;
}

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

html {
    height: 100%;
}

body {
    margin: 0;
    padding: 0;
    font-family: 'Noto Sans JP', 'Segoe UI', 'Hiragino Kaku Gothic ProN', Meiryo, sans-serif;
    background: linear-gradient(135deg, rgba(31, 60, 136, 0.5) 0%, rgba(16, 24, 32, 0.6) 100%),
        url("../img/mission-bg.png");
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    background-repeat: no-repeat;
    color: var(--brand-black);
    line-height: 1.6;
    min-height: 100%;
}

/* ========================================
   3. Accessibility
   ======================================== */
.skip-link {
    position: absolute;
    left: -999px;
    top: 1rem;
    padding: 0.5rem 1rem;
    background: var(--brand-yellow);
    color: var(--brand-black);
    font-weight: 600;
    border-radius: 0.25rem;
    text-decoration: none;
}

.skip-link:focus {
    left: 1rem;
    z-index: 1000;
}

/* ========================================
   4. Layout Containers
   ======================================== */
.container {
    width: min(1120px, 92%);
    margin: 0 auto;
}

/* ========================================
   5. Site Header & Navigation
   ======================================== */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: var(--brand-blue);
    color: var(--text-light);
    border-bottom: 4px solid var(--brand-yellow);
    box-shadow: 0 2px 12px rgba(16, 24, 32, 0.2);
    margin: 0;
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 0;
    gap: 1.5rem;
}

.brand {
    font-size: 1.25rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--text-light);
    text-decoration: none;
}

.brand:hover,
.brand:focus {
    color: var(--brand-yellow);
}

.site-nav ul {
    display: flex;
    align-items: center;
    gap: 1.75rem;
    margin: 0;
    padding: 0;
    list-style: none;
}

.site-nav a {
    color: var(--text-light);
    text-decoration: none;
    font-weight: 600;
    letter-spacing: 0.05em;
    transition: color 0.2s ease;
}

.site-nav a:hover,
.site-nav a:focus {
    color: var(--brand-yellow);
}

/* ========================================
   6. Main Content Area
   ======================================== */
.site-main {
    padding: 0 0 4rem;
    margin-top: 80px;
    /* Header height offset */
}

/* ========================================
   7. Site Footer
   ======================================== */
.site-footer {
    background: linear-gradient(180deg, var(--brand-blue) 0%, #0c1f4a 100%);
    color: var(--text-light);
    border-top: 4px solid var(--brand-yellow);
    padding: 3rem 0 2rem;
}

.footer-container {
    display: grid;
    gap: 2rem;
}

.footer-brand {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
}

.footer-brand__name {
    font-size: 1.15rem;
    font-weight: 700;
    letter-spacing: 0.1em;
}

.footer-brand__tagline {
    color: var(--text-muted);
    font-size: 0.9rem;
}

.footer-links {
    display: flex;
    flex-wrap: wrap;
    gap: 1.25rem;
}

.footer-links a {
    color: var(--text-light);
    text-decoration: none;
    font-weight: 600;
}

.footer-links a:hover,
.footer-links a:focus {
    color: var(--brand-yellow);
}

.footer-copy {
    margin: 0;
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* ========================================
   8. Common UI Components
   ======================================== */

/* Button Components */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    border-radius: 999px;
    font-weight: 700;
    letter-spacing: 0.05em;
    text-decoration: none;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.btn:hover,
.btn:focus {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(16, 24, 32, 0.25);
}

.btn--primary {
    background: var(--brand-yellow);
    color: var(--brand-black);
}

.btn--secondary {
    background: transparent;
    color: var(--text-light);
    border: 2px solid rgba(255, 255, 255, 0.5);
}

/* Section Components */
.section {
    padding: 4rem 0;
    overflow: hidden;
    background: rgba(255, 255, 255, 0.85);
    margin-bottom: 5rem;
}

.section__body {
    margin: 0 auto;
    padding: 0;
    font-family: 'Noto Sans JP', 'Segoe UI', 'Hiragino Kaku Gothic ProN', Meiryo, sans-serif;
    color: var(--brand-black);
    line-height: 1.6;
    max-width: 1200px;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.section__title {
    margin: 0;
    font-size: 1.75rem;
    color: var(--brand-blue);
    text-align: center;
    font-weight: 700;
}

/* ========================================
   9. Responsive Design
   ======================================== */
@media (max-width: 768px) {

    /* Header & Navigation */
    .nav-container {
        flex-direction: column;
        align-items: flex-start;
    }

    .site-nav ul {
        flex-wrap: wrap;
        gap: 1rem;
    }

    /* Main Content */
    .site-main {
        margin-top: 120px;
        /* Increased header height on mobile */
    }

    .section__body {
        padding: 0 1rem;
    }

    /* Footer */
    .footer-container {
        gap: 1.5rem;
    }
}