/* Modern White Theme for EarthMC Guide */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;600;700&family=Noto+Sans+JP:wght@400;500;700&display=swap');

:root {
    --primary-color: #3b82f6; /* Modern Blue */
    --secondary-color: #64748b; /* Slate Gray */
    --accent-color: #10b981; /* Emerald Green for success/tips */
    --danger-color: #ef4444; /* Red for warnings */
    --background-color: #f8fafc; /* Very light blue-grey */
    --surface-color: #ffffff;
    --text-main: #1e293b;
    --text-muted: #475569;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --header-height: 70px;
}

body {
    font-family: 'Inter', 'Noto Sans JP', sans-serif;
    line-height: 1.7;
    background-color: var(--background-color);
    color: var(--text-main);
    margin: 0;
    padding: 0;
    -webkit-font-smoothing: antialiased;
}

/* Header & Nav */
header {
    background-color: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
    height: var(--header-height);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 5%;
    box-shadow: var(--shadow-sm);
}

header h1 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-main);
    margin: 0;
    white-space: nowrap;
}

/* Language Switcher */
.language-switcher {
    display: flex;
    gap: 0.5rem;
    margin-left: auto;
    margin-right: 1rem;
}

.lang-btn {
    padding: 0.4rem 0.8rem;
    font-size: 0.85rem;
    font-weight: 600;
    text-decoration: none;
    color: var(--text-muted);
    background-color: transparent;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    transition: all 0.2s ease;
}

.lang-btn:hover {
    background-color: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.lang-btn.active {
    background-color: var(--text-main);
    color: white;
    border-color: var(--text-main);
}

/* Navigation */
nav {
    display: flex;
    align-items: center;
}

nav ul {
    display: flex;
    list-style: none;
    margin: 0;
    padding: 0;
    gap: 1.5rem;
}

nav ul li a {
    text-decoration: none;
    color: var(--text-muted);
    font-weight: 500;
    font-size: 0.95rem;
    transition: color 0.2s;
    position: relative;
}

nav ul li a:hover {
    color: var(--primary-color);
}

nav ul li a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -4px;
    left: 0;
    background-color: var(--primary-color);
    transition: width 0.3s;
}

nav ul li a:hover::after {
    width: 100%;
}

/* Mobile Menu Toggle */
.menu-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 5px;
}

.menu-toggle span {
    width: 24px;
    height: 2px;
    background-color: var(--text-main);
    transition: all 0.3s ease;
}

/* Main Content */
main {
    max-width: 1000px;
    margin: 2rem auto;
    padding: 0 1.5rem;
}

section {
    background-color: var(--surface-color);
    border-radius: var(--radius-lg);
    padding: 2.5rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

section:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

section h2 {
    font-size: 1.8rem;
    color: var(--text-main);
    margin-top: 0;
    margin-bottom: 1.5rem;
    padding-bottom: 0.75rem;
    border-bottom: 2px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

section h3 {
    font-size: 1.4rem;
    color: var(--text-main);
    margin-top: 2rem;
    margin-bottom: 1rem;
}

section h4 {
    font-size: 1.1rem;
    color: var(--secondary-color);
    margin-top: 1.5rem;
    margin-bottom: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

p {
    margin-bottom: 1rem;
    color: var(--text-muted);
}

/* Images */
img {
    max-width: 100%;
    height: auto;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    margin: 1.5rem 0;
    display: block;
}

/* Lists */
ul, ol {
    margin-bottom: 1.5rem;
    padding-left: 1.5rem;
    color: var(--text-muted);
}

li {
    margin-bottom: 0.5rem;
}

/* Code Blocks */
code {
    background-color: #f1f5f9;
    color: #e11d48;
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    font-family: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
    font-size: 0.9em;
}

pre {
    background-color: #1e293b;
    color: #f8fafc;
    padding: 1.5rem;
    border-radius: var(--radius-md);
    overflow-x: auto;
    margin: 1.5rem 0;
}

pre code {
    background-color: transparent;
    color: inherit;
    padding: 0;
}

/* Definition Lists */
dl {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 1rem 2rem;
    align-items: baseline;
}

dt {
    font-weight: 700;
    color: var(--primary-color);
    grid-column: 1;
}

dd {
    margin: 0;
    grid-column: 2;
    color: var(--text-muted);
}

/* Footer */
footer {
    text-align: center;
    padding: 3rem 0;
    color: var(--secondary-color);
    font-size: 0.9rem;
    border-top: 1px solid var(--border-color);
    margin-top: 4rem;
}

/* Responsive Design */
@media (max-width: 900px) {
    header {
        padding: 0 1.5rem;
    }

    nav ul {
        gap: 1rem;
    }
}

@media (max-width: 768px) {
    header h1 {
        font-size: 1.2rem;
    }

    .menu-toggle {
        display: flex;
        order: 3;
    }

    .language-switcher {
        margin-right: 1rem;
        order: 2;
    }
    
    nav {
        order: 4;
        width: 100%;
    }

    nav ul {
        display: none;
        flex-direction: column;
        width: 100%;
        position: absolute;
        top: var(--header-height);
        left: 0;
        background-color: var(--surface-color);
        border-bottom: 1px solid var(--border-color);
        box-shadow: var(--shadow-lg);
        padding: 1rem 0;
        gap: 0;
    }

    nav ul.show {
        display: flex;
    }

    nav ul li {
        width: 100%;
    }

    nav ul li a {
        display: block;
        padding: 1rem 2rem;
        border-left: 3px solid transparent;
    }

    nav ul li a:hover {
        background-color: var(--background-color);
        border-left-color: var(--primary-color);
    }

    nav ul li a::after {
        display: none;
    }

    /* Hamburger Animation */
    .menu-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }

    .menu-toggle.active span:nth-child(2) {
        opacity: 0;
    }

    .menu-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(5px, -5px);
    }

    section {
        padding: 1.5rem;
    }
    
    dl {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }
    
    dt {
        grid-column: 1;
        margin-top: 1rem;
    }
    
    dd {
        grid-column: 1;
    }
}