/* ========================================
   CSS Variables
   ======================================== */
:root {
    /* Colors */
    --color-text: #333;
    --color-text-dark: #444;
    --color-text-light: #666;
    --color-text-muted: #888;
    --color-link: #333;
    --color-bg: #fff;
    --color-border: #ccc;
    --color-border-light: #e5e5e5;
    --color-code-bg: #f5f2f0;

    /* Typography */
    --font-serif: Georgia, "Times New Roman", Times, serif;
    --font-sans: "Helvetica Neue", Helvetica, Arial, sans-serif;
    --font-system: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --font-mono: Consolas, Monaco, "Courier New", monospace;

    /* Font Sizes */
    --fs-base: 16px;
    --fs-title: 48px;
    --fs-h1: 38px;
    --fs-h2: 32px;
    --fs-h3: 22px;
    --fs-nav: 15px;
    --fs-small: 14px;
    --fs-large: 20px;

    /* Font Weights */
    --fw-normal: 400;
    --fw-medium: 500;
    --fw-semibold: 600;
    --fw-bold: 700;

    /* Spacing */
    --container-max: 1100px;
    --container-pad: 30px;
    --gap: 40px;

    /* Components */
    --nav-pad: 10px 20px;
    --nav-radius: 25px;
}

/* Reset & Base */
* { margin: 0; padding: 0; box-sizing: border-box; }

body {
    font-family: var(--font-serif);
    font-size: var(--fs-base);
    line-height: 1.7;
    color: var(--color-text);
    background: var(--color-bg);
}

a { color: var(--color-link); text-decoration: underline; }
a:hover { color: #000; }
strong { font-weight: var(--fw-bold); }
em { font-style: italic; }

code {
    font-family: var(--font-mono);
    font-size: var(--fs-small);
    background: var(--color-code-bg);
    padding: 2px 6px;
    border-radius: 3px;
}

pre {
    background: var(--color-code-bg);
    padding: 15px 20px;
    border-radius: 5px;
    overflow-x: auto;
    margin-bottom: 18px;
}

pre code { padding: 0; background: none; }

/* Layout */
.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--container-pad);
}

/* Header */
header { padding: 35px 0 0 0; }

.site-title {
    font-family: var(--font-sans);
    font-size: var(--fs-title);
    font-weight: var(--fw-bold);
    color: var(--color-text);
    text-decoration: none;
    display: inline-block;
    line-height: 1;
    margin-bottom: 25px;
}

.site-title:hover { color: #000; text-decoration: none; }

.title-underline {
    border-bottom: 1px solid var(--color-border);
    margin-bottom: 20px;
}

/* Navigation */
.main-nav {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: var(--gap);
}

.main-nav a {
    font-family: var(--font-system);
    font-size: var(--fs-nav);
    font-weight: var(--fw-medium);
    color: var(--color-text-dark);
    text-decoration: none;
    padding: var(--nav-pad);
    border-radius: var(--nav-radius);
}

.main-nav a:hover { background: #eee; }
.main-nav a.active { background: #444; color: #fff; font-weight: var(--fw-semibold); }

/* Placeholder */
.placeholder {
    background: linear-gradient(180deg, #a8a8a8 0%, #888 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: var(--fs-small);
    font-family: var(--font-system);
}

/* Responsive */
@media (max-width: 768px) {
    :root {
        --fs-title: 32px;
        --fs-h1: 28px;
        --fs-h2: 26px;
        --container-pad: 20px;
    }
}