* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --bg-primary: #0c0c0e;
    --bg-secondary: #1c1c1e;
    --bg-tertiary: #2c2c2e;
    --accent-primary: #ff3b30;
    --accent-secondary: #ff9500;
    --accent-tertiary: #30d158;
    --text-primary: #ffffff;
    --text-secondary: #a8a8aa;
    --text-tertiary: #6d6d70;
    --border-color: rgba(255, 255, 255, 0.08);
    --glass-bg: rgba(28, 28, 30, 0.8);
    --shadow-strong: 0 25px 50px -12px rgba(0, 0, 0, 0.8);
    --shadow-medium: 0 10px 25px -3px rgba(0, 0, 0, 0.4);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'Segoe UI', system-ui, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    font-size: 16px;
    font-weight: 400;
}

.bg-pattern {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: 
        conic-gradient(from 0deg at 50% 50%, 
            var(--accent-primary)10 0deg, 
            transparent 60deg, 
            transparent 300deg, 
            var(--accent-secondary)10 360deg),
        radial-gradient(circle at 20% 80%, var(--accent-tertiary)15 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, var(--accent-primary)15 0%, transparent 50%),
        linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
    z-index: -1;
    animation: bgShift 20s ease-in-out infinite;
}

@keyframes bgShift {
    0%, 100% { transform: scale(1) rotate(0deg); }
    50% { transform: scale(1.05) rotate(2deg); }
}
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 60px 24px;
    position: relative;
    z-index: 1;
}

.header {
    text-align: center;
    margin-bottom: 120px;
    padding: 80px 0;
    position: relative;
}

.header::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 600px;
    height: 600px;
    background: conic-gradient(from 0deg, var(--accent-primary)20, var(--accent-secondary)20, var(--accent-tertiary)20);
    border-radius: 50%;
    filter: blur(120px);
    opacity: 0.1;
    z-index: -1;
    animation: rotate 30s linear infinite;
}

@keyframes rotate {
    from { transform: translate(-50%, -50%) rotate(0deg); }
    to { transform: translate(-50%, -50%) rotate(360deg); }
}

.title {
    font-size: clamp(3.5rem, 10vw, 7rem);
    font-weight: 900;
    margin: 0;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary), var(--accent-tertiary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.05em;
    text-shadow: none;
    position: relative;
    z-index: 2;
}

.subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin: 32px auto 0;
    font-weight: 300;
    max-width: 700px;
    line-height: 1.5;
}

.tagline {
    color: var(--text-primary);
    font-weight: 600;
    margin-top: 24px;
    font-size: 1.1rem;
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border-color);
    border-radius: 50px;
    padding: 16px 32px;
    display: inline-block;
    box-shadow: var(--shadow-medium);
}
.section {
    margin: 100px 0;
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.8s ease-out forwards;
}

.section:nth-child(2) { animation-delay: 0.1s; }
.section:nth-child(3) { animation-delay: 0.2s; }
.section:nth-child(4) { animation-delay: 0.3s; }
.section:nth-child(5) { animation-delay: 0.4s; }

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

h2 {
    color: var(--text-primary);
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 48px;
    position: relative;
    padding-left: 0;
    text-align: center;
}

h2::after {
    content: '';
    position: absolute;
    bottom: -12px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background: linear-gradient(90deg, var(--accent-primary), var(--accent-secondary));
    border-radius: 2px;
}

h3 {
    color: var(--text-primary);
    font-size: 1.4rem;
    font-weight: 700;
    margin: 32px 0 20px 0;
}

.todo-list {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border-color);
    padding: 48px;
    border-radius: 24px;
    margin: 48px 0;
    box-shadow: var(--shadow-strong);
    position: relative;
    overflow: hidden;
}

.todo-list::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
}

.todo-item {
    margin: 16px 0;
    padding: 12px 0;
    font-size: 1rem;
    font-weight: 500;
    transition: all 0.3s ease;
    border-radius: 8px;
    padding-left: 16px;
}

.todo-item:hover {
    background: rgba(255, 255, 255, 0.05);
    padding-left: 24px;
}

.completed {
    color: var(--accent-tertiary);
}

.pending {
    color: var(--accent-primary);
}
.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 32px;
    margin: 60px 0;
}

.feature-card {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border-color);
    padding: 40px 32px;
    border-radius: 20px;
    text-align: center;
    transition: all 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    position: relative;
    overflow: hidden;
    cursor: pointer;
    box-shadow: var(--shadow-medium);
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.4), transparent);
}

.feature-card::after {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: conic-gradient(from 0deg, var(--accent-primary)05, transparent, var(--accent-secondary)05);
    opacity: 0;
    transition: opacity 0.4s ease;
    z-index: -1;
}

.feature-card:hover {
    transform: translateY(-12px) scale(1.02);
    background: rgba(28, 28, 30, 0.9);
    border-color: var(--accent-primary)40;
    box-shadow: var(--shadow-strong), 0 0 30px rgba(255, 59, 48, 0.2);
}

.feature-card:hover::after {
    opacity: 1;
    animation: rotate 3s linear infinite;
}

.feature-card h3 {
    margin-bottom: 16px;
    font-size: 1.2rem;
    font-weight: 700;
}

.feature-card p {
    color: var(--text-secondary);
    font-size: 1rem;
    line-height: 1.5;
}

.code-block {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 32px;
    border-radius: 16px;
    overflow-x: auto;
    margin: 32px 0;
    font-family: 'SF Mono', 'Monaco', 'Cascadia Code', 'Fira Code', monospace;
    font-size: 0.95rem;
    line-height: 1.6;
    position: relative;
    box-shadow: var(--shadow-medium);
}

.code-block::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--accent-secondary)40, transparent);
}

.cta-button {
    display: inline-block;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    color: white;
    padding: 18px 36px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 700;
    margin: 16px 12px;
    transition: all 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    border: 1px solid transparent;
    font-size: 1rem;
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-medium);
}

.cta-button::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.5s ease;
}

.cta-button:hover {
    transform: translateY(-4px) scale(1.05);
    box-shadow: var(--shadow-strong), 0 0 30px rgba(255, 59, 48, 0.4);
    background: linear-gradient(135deg, var(--accent-secondary), var(--accent-tertiary));
}

.cta-button:hover::before {
    left: 100%;
}

.footer {
    text-align: center;
    margin-top: 120px;
    padding: 60px 0;
    border-top: 1px solid var(--border-color);
    color: var(--text-tertiary);
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border-radius: 24px 24px 0 0;
}

/* レスポンシブデザイン */
@media (max-width: 768px) {
    .container {
        padding: 40px 16px;
    }
    
    .header {
        margin-bottom: 80px;
        padding: 60px 0;
    }
    
    .title {
        font-size: clamp(2.5rem, 8vw, 4rem);
    }
    
    .subtitle {
        font-size: 1.1rem;
        margin: 24px auto 0;
    }
    
    .features {
        grid-template-columns: 1fr;
        gap: 24px;
    }
    
    .feature-card {
        padding: 32px 24px;
    }
    
    .section {
        margin: 60px 0;
    }
    
    h2 {
        font-size: 2rem;
    }
    
    .todo-list {
        padding: 32px 24px;
    }
    
    .code-block {
        padding: 24px 20px;
        font-size: 0.9rem;
    }
}

/* ダークモード最適化 */
@media (prefers-color-scheme: dark) {
    :root {
        --bg-primary: #000000;
        --bg-secondary: #1a1a1a;
        --text-primary: #ffffff;
        --text-secondary: #b3b3b3;
    }
}

/* アクセシビリティ */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    .bg-pattern {
        animation: none;
    }
    
    .header::before {
        animation: none;
    }
}

/* フォーカススタイル */
.cta-button:focus-visible {
    outline: 2px solid var(--accent-primary);
    outline-offset: 4px;
}

/* セレクションスタイル */
::selection {
    background: var(--accent-primary)40;
    color: var(--text-primary);
}

/* スクロールバースタイル */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--accent-primary);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--accent-secondary);
}
