:root {
    --bg-black: #000000;
    --bg-dark-gray: #0a0a0a;
    --text-white: #ffffff;
    --text-gray: #999999;
    --text-muted: #666666;
    --border: #333333;
    --accent: #ffffff;
    /* Primary action button / High contrast */
    --accent-gray: #444444;
    --radius: 0px;
    /* Modern sharp edges for 'cool' look, or very subtle 4px */
    --font-main: 'Inter', 'Noto Sans JP', sans-serif;
}

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

body {
    font-family: var(--font-main);
    background-color: var(--bg-black);
    color: var(--text-white);
    line-height: 1.7;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

/* Base Layout */
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 40px;
}

header {
    padding: 40px 0;
    background-color: transparent;
    position: absolute;
    top: 0;
    width: 100%;
    z-index: 100;
}

.nav-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.25rem;
    font-weight: 900;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--text-white);
    text-decoration: none;
}

/* Typography Extensions */
h1,
h2,
h3 {
    font-weight: 900;
    text-transform: uppercase;
    letter-spacing: -0.02em;
}

.title-large {
    font-size: clamp(3rem, 10vw, 8rem);
    line-height: 0.9;
    margin-bottom: 40px;
}

.title-mid {
    font-size: clamp(2rem, 5vw, 4rem);
    line-height: 1.1;
    margin-bottom: 24px;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 18px 48px;
    font-weight: 800;
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    text-decoration: none;
    transition: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    cursor: pointer;
    border: 1px solid transparent;
}

.btn-primary {
    background-color: var(--text-white);
    color: var(--bg-black);
}

.btn-primary:hover {
    background-color: #cccccc;
    transform: scale(1.02);
}

.btn-outline {
    border: 1px solid var(--border);
    color: var(--text-white);
    background-color: transparent;
}

.btn-outline:hover {
    border-color: var(--text-white);
    background-color: rgba(255, 255, 255, 0.05);
}

/* Sections */
section {
    padding: 120px 0;
}

.hero {
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    position: relative;
    padding-top: 100px;
}

.hero-content {
    z-index: 2;
}

.hero p {
    color: var(--text-gray);
    font-size: 1.125rem;
    max-width: 600px;
    margin: 0 auto 48px;
    letter-spacing: 0.05em;
}

.hero-image-wrap {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 100%;
    height: 100%;
    opacity: 0.4;
    z-index: 1;
    overflow: hidden;
}

.hero-image-wrap img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

/* Feature Grid */
.features {
    background-color: var(--bg-dark-gray);
    border-top: 1px solid var(--border);
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 40px;
}

.card {
    padding: 60px 40px;
    border: 1px solid var(--border);
    transition: all 0.4s;
    background-color: var(--bg-black);
}

.card:hover {
    border-color: var(--text-muted);
    background-color: #050505;
}

.card .num {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-bottom: 24px;
    display: block;
    letter-spacing: 0.2em;
}

.card h3 {
    margin-bottom: 16px;
    font-size: 1.5rem;
}

.card p {
    color: var(--text-gray);
    font-size: 0.9375rem;
}

/* Forms (Dark Mode) */
.form-container {
    max-width: 700px;
    margin: 80px auto;
    padding: 60px;
    border: 1px solid var(--border);
    background-color: var(--bg-dark-gray);
}

.form-group {
    margin-bottom: 40px;
}

.form-group label {
    display: block;
    margin-bottom: 12px;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-gray);
}

.input-field {
    width: 100%;
    background-color: transparent;
    border: none;
    border-bottom: 1px solid var(--border);
    padding: 14px 0;
    color: var(--text-white);
    font-size: 1rem;
    border-radius: 0;
    transition: border-color 0.3s;
}

.input-field:focus {
    outline: none;
    border-color: var(--text-white);
}

/* A/B Choice Buttons - Dark */
.choice-group {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-top: 16px;
}

.choice-btn {
    padding: 24px;
    border: 1px solid var(--border);
    text-align: left;
    cursor: pointer;
    transition: all 0.3s;
    background-color: var(--bg-black);
    color: var(--text-gray);
    font-weight: 600;
}

.choice-btn:hover {
    border-color: var(--text-muted);
    color: var(--text-white);
}

.choice-btn.selected {
    border-color: var(--text-white);
    color: var(--text-white);
    background-color: var(--bg-dark-gray);
}

/* Dashboard Theme List */
.theme-list {
    display: grid;
    gap: 24px;
    margin-top: 60px;
}

.theme-card {
    padding: 40px;
    border: 1px solid var(--border);
    background-color: var(--bg-dark-gray);
    transition: all 0.3s;
}

.theme-card:hover {
    border-color: var(--text-white);
}

.theme-card h3 {
    margin-bottom: 12px;
}

.theme-card p {
    color: var(--text-gray);
}

/* Footer */
footer {
    padding: 100px 0;
    background-color: var(--bg-black);
    border-top: 1px solid var(--border);
    text-align: center;
}

footer p {
    font-size: 0.75rem;
    letter-spacing: 0.1em;
    color: var(--text-muted);
    text-transform: uppercase;
}

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

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

.fade-in {
    animation: fadeInUp 1s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}