/* ═══════════════════════════════════════════════════════
   QOLI-KI — Academic & Clean Shared Styles
   ═══════════════════════════════════════════════════════ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

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

:root {
    /* Clean Academic Light Theme */
    --white: #ffffff;
    --bg: #ffffff;
    --bg-alt: #f8fafc;
    --text: #0f172a;
    --text-secondary: #475569;
    --text-tertiary: #64748b;
    --border: #e2e8f0;
    --border-light: #f1f5f9;
    
    /* Academic Blue Accent */
    --accent: #2563eb;
    --accent-soft: #eff6ff;
    --accent-mid: #93c5fd;
    --accent-dark: #1d4ed8;
    
    /* Semantic Colors (muted for cleanliness) */
    --green: #059669;
    --green-soft: #f0fdf4;
    --green-border: #bbf7d0;
    
    --amber: #d97706;
    --amber-soft: #fffbeb;
    --amber-border: #fde68a;
    --amber-text: #92400e;
    
    --rose: #e11d48;
    --rose-soft: #fff1f2;
    
    /* Minimalist Geometry */
    --radius: 8px;
    --radius-md: 6px;
    --radius-sm: 4px;
    
    /* Flat Design: Almost no shadows, just clean borders */
    --shadow-xs: 0 1px 2px rgba(0,0,0,0.02);
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.03);
    --shadow-md: 0 2px 4px rgba(0,0,0,0.04);
    --shadow-lg: 0 4px 12px rgba(0,0,0,0.05);
    --shadow-xl: 0 8px 24px rgba(0,0,0,0.06);
}

@media (prefers-color-scheme: dark) {
    :root {
        /* Clean Academic Dark Theme */
        --white: #1e1e1e;
        --bg: #121212;
        --bg-alt: #1a1a1a;
        --text: #e2e8f0;
        --text-secondary: #94a3b8;
        --text-tertiary: #64748b;
        --border: #333333;
        --border-light: #2a2a2a;
        
        --accent: #3b82f6;
        --accent-soft: #1e293b;
        --accent-mid: #2563eb;
        --accent-dark: #60a5fa;
        
        --green-soft: #064e3b;
        --green-border: #047857;
        --amber-soft: #451a03;
        --amber-border: #78350f;
        --amber-text: #fde68a;
        --rose-soft: #4c0519;
    }
    nav {
        background: rgba(18, 18, 18, 0.95) !important;
        border-bottom: 1px solid var(--border) !important;
    }
    .btn-ghost {
        background: transparent !important;
    }
    .btn-ghost:hover {
        background: var(--bg-alt) !important;
    }
}

html { scroll-behavior: smooth; }

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.65;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

::selection { background: var(--accent-soft); color: var(--accent-dark); }
a { text-decoration: none; color: inherit; }
img { max-width: 100%; display: block; }

.container { max-width: 1000px; margin: 0 auto; padding: 0 2rem; }
.container-sm { max-width: 720px; margin: 0 auto; padding: 0 2rem; }

/* ═══════════════════════ NAV ═══════════════════════ */
nav {
    position: fixed; top: 0; left: 0; right: 0; z-index: 100;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--border);
}

.nav-inner {
    max-width: 1000px; margin: 0 auto; padding: 0 2rem;
    display: flex; justify-content: space-between; align-items: center;
    height: 60px;
}

.nav-logo {
    display: flex; align-items: center; gap: 0.5rem;
    font-size: 1.05rem; font-weight: 700; letter-spacing: -0.3px;
    color: var(--text);
}
.nav-logo-icon {
    width: 24px; height: 24px; border-radius: 4px;
    background: var(--text);
    display: flex; align-items: center; justify-content: center;
    color: var(--white); font-size: 0.75rem; font-weight: 700;
}

.nav-links { display: flex; gap: 0.5rem; align-items: center; }
.nav-links a {
    font-size: 0.85rem; font-weight: 500; color: var(--text-secondary);
    padding: 0.35rem 0.6rem; border-radius: 4px; transition: all 0.2s;
}
.nav-links a:hover { color: var(--text); background: var(--bg-alt); }
.nav-links a.active { color: var(--text); font-weight: 600; }

.nav-cta {
    border: 1px solid var(--border) !important;
    background: var(--bg) !important; color: var(--text) !important;
    border-radius: 4px !important; padding: 0.35rem 0.8rem !important;
    font-weight: 600 !important; margin-left: 0.5rem;
}
.nav-cta:hover { background: var(--bg-alt) !important; border-color: var(--text-tertiary) !important; }

/* ═══════════════════════ BUTTONS ═══════════════════════ */
.btn {
    display: inline-flex; align-items: center; gap: 0.5rem;
    padding: 0.65rem 1.25rem; border-radius: 4px;
    font-size: 0.9rem; font-weight: 600; border: 1px solid transparent; cursor: pointer;
    font-family: inherit; transition: all 0.2s;
}
.btn svg { width: 16px; height: 16px; flex-shrink: 0; }

.btn-dark {
    background: var(--text); color: var(--white);
    border-color: var(--text);
}
.btn-dark:hover { background: var(--text-secondary); border-color: var(--text-secondary); }

.btn-ghost {
    background: transparent; color: var(--text);
    border: 1px solid var(--border);
}
.btn-ghost:hover { border-color: var(--text-tertiary); background: var(--bg-alt); }

/* ═══════════════════════ SECTIONS ═══════════════════════ */
.section { padding: 5rem 0; }
.section-alt { background: var(--bg-alt); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }

.section-label {
    font-size: 0.75rem; font-weight: 600; letter-spacing: 1px;
    text-transform: uppercase; color: var(--text-tertiary); margin-bottom: 0.75rem;
}
.section-title {
    font-size: 2rem; font-weight: 700; letter-spacing: -0.02em;
    margin-bottom: 0.75rem; line-height: 1.2; color: var(--text);
}
.section-desc {
    color: var(--text-secondary); font-size: 1rem;
    max-width: 600px; margin-bottom: 2.5rem; line-height: 1.6;
}
.section-center { text-align: center; }
.section-center .section-desc { margin-left: auto; margin-right: auto; }

/* ═══════════════════════ PAGE HEADER ═══════════════════════ */
.page-header {
    padding: 8rem 0 4rem; text-align: center;
}
.page-header h1 {
    font-size: clamp(2rem, 4vw, 2.5rem);
    font-weight: 700; letter-spacing: -0.02em;
    margin-bottom: 1rem; color: var(--text);
}
.page-header p {
    color: var(--text-secondary); font-size: 1.05rem;
    max-width: 600px; margin: 0 auto; line-height: 1.6;
}

/* ═══════════════════════ CARDS ═══════════════════════ */
.card {
    background: var(--white); border: 1px solid var(--border);
    border-radius: var(--radius); padding: 2rem;
    box-shadow: var(--shadow-sm);
}

/* ═══════════════════════ INLINE CODE ═══════════════════════ */
.inline-code {
    font-family: 'Consolas','Monaco', monospace;
    background: var(--bg-alt); padding: 0.15rem 0.35rem;
    border-radius: 3px; font-size: 0.85em;
    color: var(--text); border: 1px solid var(--border);
}

/* ═══════════════════════ CODE BLOCK ═══════════════════════ */
.cmd-block {
    background: var(--bg-alt); border: 1px solid var(--border);
    border-radius: var(--radius-sm); margin: 1rem 0; overflow: hidden;
}
.cmd-bar {
    display: flex; align-items: center; justify-content: space-between;
    padding: 0.5rem 1rem; background: var(--border-light);
    border-bottom: 1px solid var(--border);
}
.cmd-bar-label { font-size: 0.75rem; color: var(--text-secondary); font-weight: 600; font-family: 'Consolas', monospace; }

.copy-btn {
    background: transparent; border: 1px solid var(--border);
    color: var(--text-secondary); padding: 0.2rem 0.5rem; border-radius: 4px;
    font-size: 0.7rem; font-weight: 500; cursor: pointer;
    font-family: 'Inter', sans-serif; transition: all 0.2s;
    display: inline-flex; align-items: center; gap: 0.3rem;
}
.copy-btn:hover { background: var(--bg); color: var(--text); border-color: var(--text-tertiary); }
.copy-btn.copied { background: var(--green-soft); border-color: var(--green-border); color: var(--green); }
.copy-btn svg { width: 12px; height: 12px; }

.cmd-body { padding: 1rem; display: flex; align-items: flex-start; overflow-x: auto; }
.cmd-prompt {
    color: var(--text-tertiary); font-family: 'Consolas', monospace;
    font-size: 0.85rem; margin-right: 0.75rem;
    user-select: none; white-space: nowrap; font-weight: 400;
}
.cmd-code {
    font-family: 'Consolas', monospace; font-size: 0.85rem;
    color: var(--text); word-break: break-all; line-height: 1.6;
}

/* Syntax Highlighting - Muted Academic Theme */
.ck { color: #d97706; font-weight: 600; } /* keyword */
.cf { color: #2563eb; } /* function */
.cs { color: #059669; } /* string */
.cc { color: #64748b; font-style: italic; } /* comment */
.cn { color: #e11d48; } /* number */
.cv { color: #0f172a; font-weight: 600; } /* variable */
@media (prefers-color-scheme: dark) {
    .ck { color: #fbbf24; }
    .cf { color: #60a5fa; }
    .cs { color: #34d399; }
    .cc { color: #94a3b8; }
    .cn { color: #fb7185; }
    .cv { color: #f8fafc; }
}
.code-line { display: block; white-space: pre; }

/* ═══════════════════════ WARNING / TIP BOXES ═══════════════════════ */
.warning-box {
    background: var(--amber-soft); border: 1px solid var(--amber-border);
    border-radius: var(--radius-sm); padding: 1rem 1.25rem;
    margin: 1.25rem 0; display: flex; gap: 0.75rem;
}
.warning-box .box-icon { font-size: 1.2rem; flex-shrink: 0; line-height: 1.6; }
.warning-box strong { color: var(--amber-text); display: block; margin-bottom: 0.1rem; font-size: 0.85rem; }
.warning-box p { color: var(--amber-text); font-size: 0.85rem; line-height: 1.6; margin: 0; }

.tip-box {
    background: var(--green-soft); border: 1px solid var(--green-border);
    border-radius: var(--radius-sm); padding: 0.85rem 1.25rem;
    margin: 1rem 0; display: flex; gap: 0.75rem;
    font-size: 0.85rem; color: #065f46; line-height: 1.6;
}
.tip-box .box-icon { font-size: 1.1rem; flex-shrink: 0; line-height: 1.6; }

/* ═══════════════════════ FOOTER ═══════════════════════ */
footer {
    padding: 3rem 0; border-top: 1px solid var(--border);
    margin-top: 3rem; background: var(--bg-alt);
}
.footer-inner {
    display: flex; justify-content: space-between; align-items: center;
    flex-wrap: wrap; gap: 1rem;
}
.footer-text { font-size: 0.8rem; color: var(--text-tertiary); }
.footer-links { display: flex; gap: 1.5rem; }
.footer-links a { font-size: 0.8rem; color: var(--text-tertiary); transition: color 0.2s; }
.footer-links a:hover { color: var(--text); }

/* ═══════════════════════ ANIMATIONS ═══════════════════════ */
.reveal {
    opacity: 0; transform: translateY(10px);
    transition: opacity 0.5s ease-out, transform 0.5s ease-out;
}
.reveal.visible { opacity: 1; transform: translateY(0); }

/* ═══════════════════════ RESPONSIVE ═══════════════════════ */
@media (max-width: 900px) {
    .nav-links a:not(.nav-cta) { display: none; }
    .section { padding: 4rem 0; }
}
@media (max-width: 640px) {
    .page-header { padding: 6rem 0 2rem; }
    .page-header h1 { font-size: 1.75rem; }
}