/*
 * =============================================
 * BookzCart — Design System
 * =============================================
 *
 * Editorial-first, literary aesthetic.
 * Dark ink & warm amber — a library at midnight.
 *
 * Naming: --bkz-{category}-{property}-{modifier}
 */

/* --- Google Fonts --- */
@import url('https://fonts.googleapis.com/css2?family=Playfair+Display:ital,wght@0,400;0,500;0,600;0,700;1,400;1,500&family=Inter:wght@300;400;500;600;700&family=Noto+Serif+Tamil:wght@400;500;600;700&display=swap');

/* =============================================
   1. CSS Custom Properties (Design Tokens)
   ============================================= */

:root {
    /* --- Color Palette --- */
    /* Ink: deep, rich darks */
    --bkz-ink-900: #07070d;
    --bkz-ink-800: #0c0c16;
    --bkz-ink-700: #111120;
    --bkz-ink-600: #17172a;
    --bkz-ink-500: #1e1e34;
    --bkz-ink-400: #2a2a44;
    --bkz-ink-300: #3a3a58;
    --bkz-ink-200: #52526e;
    --bkz-ink-100: #7a7a96;

    /* Amber: warm accent — the glow of a reading lamp */
    --bkz-amber-500: #c8a45a;
    --bkz-amber-400: #d4b06a;
    --bkz-amber-300: #e0c07e;
    --bkz-amber-200: #ecdba8;
    --bkz-amber-100: #f5edd0;
    --bkz-amber-600: #b08c40;
    --bkz-amber-700: #8a6e30;

    /* Terracotta: secondary warm tone */
    --bkz-terra-500: #b5654a;
    --bkz-terra-400: #c9785c;
    --bkz-terra-300: #d99478;

    /* Sage: muted green for success/nature */
    --bkz-sage-500: #6b8f71;
    --bkz-sage-400: #82a788;
    --bkz-sage-300: #a3c4a8;

    /* Parchment: warm text colors */
    --bkz-parch-50: #faf7f0;
    --bkz-parch-100: #f5f0e6;
    --bkz-parch-200: #e8e0d0;
    --bkz-parch-300: #d4cbb8;
    --bkz-parch-400: #b3a890;
    --bkz-parch-500: #918672;

    /* Error */
    --bkz-error: #d94f4f;
    --bkz-error-soft: rgba(217, 79, 79, 0.15);

    /* --- Semantic Colors --- */
    --bkz-bg: var(--bkz-ink-800);
    --bkz-bg-elevated: var(--bkz-ink-700);
    --bkz-bg-surface: var(--bkz-ink-600);
    --bkz-bg-card: var(--bkz-ink-600);
    --bkz-bg-card-hover: var(--bkz-ink-500);

    --bkz-text: var(--bkz-parch-100);
    --bkz-text-secondary: var(--bkz-parch-400);
    --bkz-text-muted: var(--bkz-ink-100);

    --bkz-accent: var(--bkz-amber-500);
    --bkz-accent-hover: var(--bkz-amber-400);
    --bkz-accent-text: var(--bkz-ink-900);

    --bkz-border: rgba(255, 255, 255, 0.06);
    --bkz-border-accent: rgba(200, 164, 90, 0.25);

    /* --- Typography --- */
    --bkz-font-display: 'Playfair Display', 'Noto Serif Tamil', Georgia, serif;
    --bkz-font-body: 'Inter', 'Noto Serif Tamil', system-ui, sans-serif;
    --bkz-font-tamil: 'Noto Serif Tamil', serif;

    /* Size scale (fluid) */
    --bkz-text-xs: clamp(0.7rem, 0.65rem + 0.25vw, 0.75rem);
    --bkz-text-sm: clamp(0.8rem, 0.75rem + 0.25vw, 0.875rem);
    --bkz-text-base: clamp(0.9rem, 0.85rem + 0.25vw, 1rem);
    --bkz-text-md: clamp(1rem, 0.9rem + 0.5vw, 1.125rem);
    --bkz-text-lg: clamp(1.15rem, 1rem + 0.75vw, 1.35rem);
    --bkz-text-xl: clamp(1.4rem, 1.15rem + 1.25vw, 1.75rem);
    --bkz-text-2xl: clamp(1.8rem, 1.4rem + 2vw, 2.5rem);
    --bkz-text-3xl: clamp(2.2rem, 1.6rem + 3vw, 3.5rem);
    --bkz-text-4xl: clamp(2.8rem, 2rem + 4vw, 5rem);

    /* Line heights */
    --bkz-leading-tight: 1.15;
    --bkz-leading-snug: 1.3;
    --bkz-leading-normal: 1.6;
    --bkz-leading-relaxed: 1.8;

    /* Letter spacing */
    --bkz-tracking-tight: -0.02em;
    --bkz-tracking-normal: 0;
    --bkz-tracking-wide: 0.04em;
    --bkz-tracking-wider: 0.08em;
    --bkz-tracking-caps: 0.12em;

    /* --- Spacing --- */
    --bkz-space-xs: 0.25rem;
    --bkz-space-sm: 0.5rem;
    --bkz-space-md: 1rem;
    --bkz-space-lg: 1.5rem;
    --bkz-space-xl: 2rem;
    --bkz-space-2xl: 3rem;
    --bkz-space-3xl: 4.5rem;
    --bkz-space-4xl: 6rem;
    --bkz-space-5xl: 8rem;

    /* --- Layout --- */
    --bkz-max-width: 1280px;
    --bkz-max-width-narrow: 800px;
    --bkz-max-width-wide: 1440px;
    --bkz-gutter: clamp(1rem, 2vw, 2.5rem);
    --bkz-header-height: 72px;

    /* --- Radius --- */
    --bkz-radius-sm: 4px;
    --bkz-radius-md: 8px;
    --bkz-radius-lg: 12px;
    --bkz-radius-xl: 20px;
    --bkz-radius-full: 9999px;

    /* --- Shadows --- */
    --bkz-shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
    --bkz-shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --bkz-shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.5);
    --bkz-shadow-glow: 0 0 30px rgba(200, 164, 90, 0.15);
    --bkz-shadow-card: 0 2px 8px rgba(0, 0, 0, 0.3), 0 0 0 1px var(--bkz-border);

    /* --- Transitions --- */
    --bkz-ease-out: cubic-bezier(0.22, 1, 0.36, 1);
    --bkz-ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
    --bkz-duration-fast: 150ms;
    --bkz-duration-normal: 250ms;
    --bkz-duration-slow: 400ms;

    /* --- z-index scale --- */
    --bkz-z-base: 0;
    --bkz-z-elevated: 10;
    --bkz-z-dropdown: 100;
    --bkz-z-sticky: 200;
    --bkz-z-overlay: 500;
    --bkz-z-modal: 1000;
    --bkz-z-toast: 1500;
}

/* =============================================
   2. Reset & Base
   ============================================= */

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

html {
    font-size: 16px;
    -webkit-text-size-adjust: 100%;
    scroll-behavior: smooth;
    scrollbar-color: var(--bkz-ink-400) var(--bkz-ink-800);
}

body {
    font-family: var(--bkz-font-body);
    font-size: var(--bkz-text-base);
    line-height: var(--bkz-leading-normal);
    color: var(--bkz-text);
    background-color: var(--bkz-bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
    min-height: 100vh;
}

/* Scrollbar styling */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: var(--bkz-ink-800); }
::-webkit-scrollbar-thumb { background: var(--bkz-ink-400); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--bkz-ink-300); }

img, video, svg { display: block; max-width: 100%; height: auto; }

a {
    color: var(--bkz-accent);
    text-decoration: none;
    transition: color var(--bkz-duration-fast) var(--bkz-ease-out);
}
a:hover { color: var(--bkz-accent-hover); }

button, input, select, textarea {
    font-family: inherit;
    font-size: inherit;
    color: inherit;
    background: none;
    border: none;
    outline: none;
}

button { cursor: pointer; }

ul, ol { list-style: none; }

/* Selection */
::selection {
    background: var(--bkz-amber-500);
    color: var(--bkz-ink-900);
}

/* Focus styles */
:focus-visible {
    outline: 2px solid var(--bkz-accent);
    outline-offset: 2px;
}

/* =============================================
   3. Typography
   ============================================= */

h1, h2, h3, h4, h5, h6 {
    font-family: var(--bkz-font-display);
    font-weight: 600;
    line-height: var(--bkz-leading-tight);
    letter-spacing: var(--bkz-tracking-tight);
    color: var(--bkz-parch-50);
}

h1 { font-size: var(--bkz-text-3xl); }
h2 { font-size: var(--bkz-text-2xl); }
h3 { font-size: var(--bkz-text-xl); }
h4 { font-size: var(--bkz-text-lg); }

p { margin-bottom: 1em; }
p:last-child { margin-bottom: 0; }

.text-editorial {
    font-family: var(--bkz-font-display);
    font-size: var(--bkz-text-md);
    line-height: var(--bkz-leading-relaxed);
    color: var(--bkz-parch-200);
    font-style: italic;
}

.text-label {
    font-size: var(--bkz-text-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: var(--bkz-tracking-caps);
    color: var(--bkz-amber-500);
}

.text-tamil {
    font-family: var(--bkz-font-tamil);
}

/* =============================================
   4. Layout Utilities
   ============================================= */

.container {
    width: 100%;
    max-width: var(--bkz-max-width);
    margin-inline: auto;
    padding-inline: var(--bkz-gutter);
}

.container--narrow { max-width: var(--bkz-max-width-narrow); }
.container--wide { max-width: var(--bkz-max-width-wide); }

.section {
    padding-block: var(--bkz-space-3xl);
}

.section--tight {
    padding-block: var(--bkz-space-2xl);
}

.section-header {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    margin-bottom: var(--bkz-space-xl);
    gap: var(--bkz-space-md);
    flex-wrap: wrap;
}

.section-header__title {
    font-size: var(--bkz-text-2xl);
    position: relative;
}

.section-header__link {
    font-size: var(--bkz-text-sm);
    font-weight: 500;
    letter-spacing: var(--bkz-tracking-wide);
    text-transform: uppercase;
    color: var(--bkz-amber-500);
    display: flex;
    align-items: center;
    gap: var(--bkz-space-xs);
    transition: gap var(--bkz-duration-normal) var(--bkz-ease-out);
}

.section-header__link:hover {
    gap: var(--bkz-space-sm);
}

.section-header__link::after {
    content: '→';
    transition: transform var(--bkz-duration-normal) var(--bkz-ease-out);
}

.section-header__link:hover::after {
    transform: translateX(4px);
}

/* Grid */
.grid {
    display: grid;
    gap: var(--bkz-space-lg);
}

.grid--books {
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
}

.grid--collections {
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
}

.grid--moods {
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: var(--bkz-space-md);
}

@media (min-width: 768px) {
    .grid--books { grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); }
}

@media (min-width: 1024px) {
    .grid--books { grid-template-columns: repeat(5, 1fr); }
}

/* Horizontal scroll */
.hscroll {
    display: flex;
    gap: var(--bkz-space-lg);
    overflow-x: auto;
    scroll-snap-type: x mandatory;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
    padding-bottom: var(--bkz-space-sm);
}

.hscroll::-webkit-scrollbar { display: none; }
.hscroll > * { scroll-snap-align: start; flex-shrink: 0; }

/* Visually hidden */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* Separator */
.divider {
    border: none;
    height: 1px;
    background: var(--bkz-border);
    margin-block: var(--bkz-space-2xl);
}