/* ============================================
   東大航空宇宙入試ガイド - Design System
   Professional + Personal Aesthetic
   ============================================ */

/* --- CSS Custom Properties --- */
:root {
    /* Colors - Dark Navy + Coral Red */
    --color-primary: #0A0631;
    --color-primary-light: #1A1654;
    --color-primary-dark: #050318;

    --color-accent: #E53E3E;
    --color-accent-light: #F56565;
    --color-accent-dark: #C53030;

    --color-secondary: #4a5568;
    --color-muted: #718096;

    --color-background: #f7fafc;
    --color-surface: #ffffff;
    --color-surface-alt: #edf2f7;

    --color-text: #1a202c;
    --color-text-light: #4a5568;
    --color-text-inverse: #ffffff;

    --color-success: #38a169;
    --color-error: #e53e3e;

    /* Typography */
    --font-primary: 'Noto Sans JP', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-accent: 'Zen Maru Gothic', serif;

    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 1.875rem;
    --text-4xl: 2.25rem;
    --text-5xl: 3rem;

    --leading-tight: 1.25;
    --leading-normal: 1.6;
    --leading-relaxed: 1.75;

    /* Spacing */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;
    --space-24: 6rem;

    /* Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 400ms ease;

    /* Container */
    --container-max: 1200px;
    --container-narrow: 800px;
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-primary);
    font-size: var(--text-base);
    line-height: var(--leading-normal);
    color: var(--color-text);
    background-color: var(--color-background);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

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

a:hover {
    color: var(--color-accent);
}

ul,
ol {
    list-style: none;
}

/* --- Typography --- */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-family: var(--font-primary);
    font-weight: 700;
    line-height: var(--leading-tight);
    color: var(--color-primary);
}

h1 {
    font-size: var(--text-4xl);
    margin-bottom: var(--space-6);
}

h2 {
    font-size: var(--text-3xl);
    margin-bottom: var(--space-4);
}

h3 {
    font-size: var(--text-2xl);
    margin-bottom: var(--space-3);
}

h4 {
    font-size: var(--text-xl);
    margin-bottom: var(--space-2);
}

p {
    margin-bottom: var(--space-4);
    color: var(--color-text-light);
}

.text-accent {
    font-family: var(--font-accent);
}

/* --- Layout --- */
.container {
    width: 100%;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--space-6);
}

.container-narrow {
    max-width: var(--container-narrow);
}

.section {
    padding: var(--space-20) 0;
}

.section-alt {
    background-color: var(--color-surface);
}

/* --- Header & Navigation --- */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-sm);
    z-index: 1000;
    transition: all var(--transition-base);
}

.header.scrolled {
    box-shadow: var(--shadow-md);
}

.pen-name {
    font-size: var(--text-sm);
    color: rgba(255, 255, 255, 0.9);
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    position: absolute;
    top: var(--space-4);
    right: var(--space-4);
}

@media (max-width: 768px) {
    .pen-name {
        font-size: var(--text-xs);
        top: var(--space-2);
        right: var(--space-2);
    }
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-4) 0;
}

.nav-logo {
    font-size: var(--text-xl);
    font-weight: 700;
    color: var(--color-primary);
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.nav-logo span {
    color: var(--color-accent);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: var(--space-8);
}

.nav-link {
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--color-secondary);
    position: relative;
    padding: var(--space-2) 0;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--color-accent);
    transition: width var(--transition-base);
}

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

.nav-link:hover,
.nav-link.active {
    color: var(--color-primary);
}

/* Mobile Navigation */
.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--space-2);
}

.nav-toggle span {
    width: 24px;
    height: 2px;
    background-color: var(--color-primary);
    transition: all var(--transition-fast);
}

@media (max-width: 768px) {
    .nav-toggle {
        display: flex;
    }

    .nav-links {
        position: fixed;
        top: 60px;
        left: 0;
        right: 0;
        background-color: var(--color-surface);
        flex-direction: column;
        padding: var(--space-6);
        gap: var(--space-4);
        box-shadow: var(--shadow-lg);
        transform: translateY(-100%);
        opacity: 0;
        pointer-events: none;
        transition: all var(--transition-base);
    }

    .nav-links.active {
        transform: translateY(0);
        opacity: 1;
        pointer-events: auto;
    }
}

/* --- Hero Section --- */
.hero {
    padding-top: calc(var(--space-24) + 60px);
    padding-bottom: var(--space-20);
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
    color: var(--color-text-inverse);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 700px;
}

.hero h1 {
    color: var(--color-text-inverse);
    font-size: var(--text-5xl);
    margin-bottom: var(--space-4);
}

.hero-subtitle {
    font-size: var(--text-xl);
    opacity: 0.9;
    margin-bottom: var(--space-8);
    color: var(--color-text-inverse);
}

.hero-journey {
    display: inline-flex;
    align-items: center;
    gap: var(--space-3);
    background-color: rgba(255, 255, 255, 0.15);
    padding: var(--space-3) var(--space-5);
    border-radius: var(--radius-full);
    font-size: var(--text-sm);
    margin-bottom: var(--space-6);
}

.hero-journey .arrow {
    color: var(--color-accent-light);
    font-weight: bold;
}

/* --- Cards --- */
.card {
    background-color: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: var(--space-8);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
}

.card-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--color-accent) 0%, var(--color-accent-light) 100%);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--space-4);
    font-size: var(--text-2xl);
}

.card-title {
    font-size: var(--text-xl);
    margin-bottom: var(--space-2);
}

.card-text {
    font-size: var(--text-sm);
    color: var(--color-muted);
    margin-bottom: var(--space-4);
}

.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--space-6);
}

/* --- Buttons --- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-6);
    font-size: var(--text-sm);
    font-weight: 600;
    border-radius: var(--radius-md);
    border: none;
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-accent) 0%, var(--color-accent-dark) 100%);
    color: var(--color-text-inverse);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(229, 62, 62, 0.4);
    color: var(--color-text-inverse);
}

.btn-secondary {
    background-color: var(--color-surface);
    color: var(--color-primary);
    border: 2px solid var(--color-primary);
}

.btn-secondary:hover {
    background-color: var(--color-primary);
    color: var(--color-text-inverse);
}

.btn-outline {
    background-color: transparent;
    color: var(--color-text-inverse);
    border: 2px solid var(--color-text-inverse);
}

.btn-outline:hover {
    background-color: var(--color-text-inverse);
    color: var(--color-primary);
}

.btn-lg {
    padding: var(--space-4) var(--space-8);
    font-size: var(--text-base);
}

/* --- Timeline --- */
.timeline {
    position: relative;
    padding-left: var(--space-8);
}

.timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 3px;
    background: linear-gradient(to bottom, var(--color-accent), var(--color-primary));
    border-radius: var(--radius-full);
}

.timeline-item {
    position: relative;
    padding-bottom: var(--space-10);
}

.timeline-item:last-child {
    padding-bottom: 0;
}

.timeline-dot {
    position: absolute;
    left: calc(-1 * var(--space-8) - 6px);
    width: 15px;
    height: 15px;
    background-color: var(--color-accent);
    border-radius: 50%;
    border: 3px solid var(--color-surface);
    box-shadow: var(--shadow-md);
}

.timeline-content {
    background-color: var(--color-surface);
    padding: var(--space-6);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.timeline-date {
    font-size: var(--text-sm);
    color: var(--color-accent);
    font-weight: 600;
    margin-bottom: var(--space-2);
}

.timeline-title {
    font-size: var(--text-lg);
    margin-bottom: var(--space-2);
}

/* --- Info Boxes --- */
.info-box {
    background-color: var(--color-surface-alt);
    border-left: 4px solid var(--color-accent);
    padding: var(--space-6);
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
    margin: var(--space-6) 0;
}

.info-box-title {
    font-size: var(--text-lg);
    color: var(--color-primary);
    margin-bottom: var(--space-2);
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.info-box p {
    margin-bottom: 0;
}

/* --- Subject List --- */
.subject-list {
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
}

.subject-item {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: var(--space-4);
    background-color: var(--color-surface);
    border-radius: var(--radius-md);
    border: 1px solid var(--color-surface-alt);
    transition: all var(--transition-fast);
}

.subject-item:hover {
    border-color: var(--color-accent);
    box-shadow: var(--shadow-sm);
}

.subject-number {
    width: 32px;
    height: 32px;
    background-color: var(--color-primary);
    color: var(--color-text-inverse);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--text-sm);
    font-weight: 600;
    flex-shrink: 0;
}

.subject-name {
    font-weight: 500;
    color: var(--color-text);
}

/* --- Score Table --- */
.score-table {
    width: 100%;
    border-collapse: collapse;
    margin: var(--space-6) 0;
}

.score-table th,
.score-table td {
    padding: var(--space-4);
    text-align: left;
    border-bottom: 1px solid var(--color-surface-alt);
}

.score-table th {
    background-color: var(--color-primary);
    color: var(--color-text-inverse);
    font-weight: 600;
}

.score-table th:first-child {
    border-radius: var(--radius-md) 0 0 0;
}

.score-table th:last-child {
    border-radius: 0 var(--radius-md) 0 0;
}

.score-table tr:hover td {
    background-color: var(--color-surface-alt);
}

/* --- Forms --- */
.form-group {
    margin-bottom: var(--space-5);
}

.form-label {
    display: block;
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--color-text);
    margin-bottom: var(--space-2);
}

.form-input,
.form-textarea {
    width: 100%;
    padding: var(--space-3) var(--space-4);
    font-size: var(--text-base);
    font-family: var(--font-primary);
    border: 2px solid var(--color-surface-alt);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    background-color: var(--color-surface);
}

.form-input:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px rgba(229, 62, 62, 0.2);
}

.form-textarea {
    min-height: 150px;
    resize: vertical;
}

.form-error {
    font-size: var(--text-sm);
    color: var(--color-error);
    margin-top: var(--space-1);
}

/* --- Footer --- */
.footer {
    background-color: var(--color-primary-dark);
    color: var(--color-text-inverse);
    padding: var(--space-12) 0 var(--space-6);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--space-8);
    margin-bottom: var(--space-8);
}

.footer-section h4 {
    color: var(--color-text-inverse);
    margin-bottom: var(--space-4);
}

.footer-section a {
    color: rgba(255, 255, 255, 0.7);
    display: block;
    padding: var(--space-1) 0;
}

.footer-section a:hover {
    color: var(--color-accent-light);
}

.footer-bottom {
    text-align: center;
    padding-top: var(--space-6);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    font-size: var(--text-sm);
    opacity: 0.7;
}

/* --- Utility Classes --- */
.text-center {
    text-align: center;
}

.text-accent-color {
    color: var(--color-accent);
}

.mb-0 {
    margin-bottom: 0;
}

.mb-4 {
    margin-bottom: var(--space-4);
}

.mb-8 {
    margin-bottom: var(--space-8);
}

.mt-4 {
    margin-top: var(--space-4);
}

.mt-8 {
    margin-top: var(--space-8);
}

.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity var(--transition-slow), transform var(--transition-slow);
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* --- Responsive --- */
@media (max-width: 768px) {
    :root {
        --text-4xl: 1.875rem;
        --text-5xl: 2.25rem;
    }

    .hero {
        padding-top: calc(var(--space-16) + 60px);
        padding-bottom: var(--space-12);
    }

    .section {
        padding: var(--space-12) 0;
    }

    .cards-grid {
        grid-template-columns: 1fr;
    }

    .hero-journey {
        flex-direction: column;
        gap: var(--space-2);
    }
}

/* --- Animations --- */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

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

@keyframes pulse {

    0%,
    100% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.05);
    }
}

.animate-fade-in-up {
    animation: fadeInUp 0.6s ease-out forwards;
}

.animate-pulse:hover {
    animation: pulse 0.5s ease-in-out;
}

/* Coming Soon Badge */
.coming-soon-badge {
    display: inline-block;
    background: linear-gradient(135deg, var(--color-muted), var(--color-secondary));
    color: var(--color-text-inverse);
    font-size: var(--text-sm);
    padding: var(--space-2) var(--space-4);
    border-radius: var(--radius-full);
    font-weight: 500;
}

/* CTA Section */
.cta-section {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
    padding: var(--space-16) 0;
    text-align: center;
    color: var(--color-text-inverse);
}

.cta-section h2 {
    color: var(--color-text-inverse);
}

.cta-section p {
    color: rgba(255, 255, 255, 0.9);
    max-width: 600px;
    margin: 0 auto var(--space-8);
}

/* Q&A Section */
.qa-item {
    background-color: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: var(--space-6);
    margin-bottom: var(--space-4);
    border-left: 4px solid var(--color-primary);
}

.qa-question {
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: var(--space-3);
    display: flex;
    gap: var(--space-3);
}

.qa-question::before {
    content: 'Q';
    background-color: var(--color-primary);
    color: var(--color-text-inverse);
    width: 24px;
    height: 24px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--text-sm);
    flex-shrink: 0;
}

.qa-answer {
    padding-left: 36px;
    color: var(--color-text-light);
}

.qa-answer::before {
    content: 'A';
    background-color: var(--color-accent);
    color: var(--color-text-inverse);
    width: 24px;
    height: 24px;
    border-radius: 50%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: var(--text-sm);
    margin-right: var(--space-3);
    margin-left: -36px;
}