/* ═══════════════════════════════════════════════════════════════════════════
   BHARAT ECOFUELS — DESIGN SYSTEM
   Premium International Green Energy Brand
   ═══════════════════════════════════════════════════════════════════════════ */

/* ─── DESIGN TOKENS ───────────────────────────────────────────────────────── */
:root {
    /* Primary — Deep emerald luxury */
    --eco-ink:        #0a1f1c;   /* deepest background */
    --eco-deep:       #0d3b2e;   /* forest green */
    --eco-corporate:  #115e3b;   /* corporate green */
    --eco-primary:    #15803d;   /* primary action */
    --eco-bright:     #16a34a;   /* CTA bright */
    --eco-glow:       #34d399;   /* glow / highlight */
    --eco-mint:       #d1fae5;   /* soft tint */
    --eco-fog:        #ecfdf5;   /* faintest tint */

    /* Neutral & luxury */
    --ink:            #0b1014;
    --slate-900:      #111827;
    --slate-700:      #374151;
    --slate-500:      #6b7280;
    --slate-400:      #9ca3af;
    --slate-300:      #d1d5db;
    --slate-200:      #e5e7eb;
    --slate-100:      #f3f4f6;
    --slate-50:       #f9fafb;
    --cream:          #faf7f0;
    --pure:           #ffffff;

    /* Gold luxury accent */
    --gold:           #d4af37;
    --gold-soft:      #e6c869;
    --gold-deep:      #a98a2c;

    /* Status */
    --success:        #10b981;
    --danger:         #dc2626;
    --warning:        #f59e0b;

    /* Premium gradients */
    --grad-hero:      linear-gradient(135deg, #0a1f1c 0%, #0d3b2e 45%, #115e3b 100%);
    --grad-emerald:   linear-gradient(135deg, #15803d 0%, #16a34a 50%, #34d399 100%);
    --grad-dark:      linear-gradient(180deg, #0a1f1c 0%, #0d3b2e 100%);
    --grad-mesh:      radial-gradient(at 18% 12%, rgba(52,211,153,0.18) 0px, transparent 50%),
                      radial-gradient(at 82% 88%, rgba(212,175,55,0.10) 0px, transparent 50%),
                      radial-gradient(at 50% 50%, rgba(17,94,59,0.25) 0px, transparent 60%);
    --grad-cream:     linear-gradient(180deg, #faf7f0 0%, #ffffff 100%);

    /* Glassmorphism */
    --glass-bg:       rgba(255, 255, 255, 0.06);
    --glass-bg-light: rgba(255, 255, 255, 0.85);
    --glass-border:   rgba(255, 255, 255, 0.12);
    --glass-blur:     20px;

    /* Typography scale */
    --font-display:   'Cormorant Garamond', 'Playfair Display', Georgia, serif;
    --font-body:      'Manrope', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;

    --fs-xs:    0.75rem;     /* 12 */
    --fs-sm:    0.875rem;    /* 14 */
    --fs-base:  1rem;        /* 16 */
    --fs-md:    1.125rem;    /* 18 */
    --fs-lg:    1.25rem;     /* 20 */
    --fs-xl:    1.5rem;      /* 24 */
    --fs-2xl:   2rem;        /* 32 */
    --fs-3xl:   2.5rem;      /* 40 */
    --fs-4xl:   3.25rem;     /* 52 */
    --fs-5xl:   4.25rem;     /* 68 */
    --fs-hero:  clamp(2.5rem, 5.5vw + 1rem, 5.25rem);

    --lh-tight: 1.08;
    --lh-snug:  1.25;
    --lh-base:  1.6;
    --lh-loose: 1.85;

    --tracking-tight: -0.02em;
    --tracking-snug:  -0.01em;
    --tracking-wide:  0.08em;
    --tracking-eyebrow: 0.18em;

    /* Spacing — 4-pt grid */
    --space-1:  0.25rem;
    --space-2:  0.5rem;
    --space-3:  0.75rem;
    --space-4:  1rem;
    --space-5:  1.25rem;
    --space-6:  1.5rem;
    --space-8:  2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;
    --space-24: 6rem;
    --space-32: 8rem;

    /* Radius */
    --r-xs:  4px;
    --r-sm:  8px;
    --r-md:  12px;
    --r-lg:  18px;
    --r-xl:  24px;
    --r-2xl: 32px;
    --r-pill: 999px;

    /* Shadows — softer, more premium (less dark, more diffused) */
    --shadow-sm:    0 1px 2px rgba(10, 31, 28, 0.04);
    --shadow:       0 2px 10px rgba(10, 31, 28, 0.05);
    --shadow-md:    0 8px 24px rgba(10, 31, 28, 0.06);
    --shadow-lg:    0 16px 40px rgba(10, 31, 28, 0.08);
    --shadow-xl:    0 24px 60px rgba(10, 31, 28, 0.10);
    --shadow-glow:  0 8px 32px rgba(52, 211, 153, 0.18);
    --shadow-gold:  0 8px 24px rgba(212, 175, 55, 0.22);
    --shadow-inner: inset 0 1px 0 rgba(255,255,255,0.08);

    /* Layout */
    --maxw:     1320px;
    --maxw-md:  1080px;
    --maxw-sm:  860px;
    --maxw-xl:  1560px;
    --nav-h:    96px;
    --nav-h-mobile: 72px;

    /* ─── BREAKPOINT SCALE (for documentation; @media can't use vars) ──────
       --bp-xs:  360px   compact phones (iPhone SE)
       --bp-sm:  480px   large phones (iPhone Plus, Pixel)
       --bp-md:  768px   tablets (iPad portrait)
       --bp-lg:  1024px  laptops (iPad Pro, small laptops)
       --bp-xl:  1280px  desktops
       --bp-2xl: 1680px  ultra-wide
       Use only these values in @media queries. ─────────────────────────── */

    /* ─── Z-INDEX SCALE (single source of truth) ───────────────────────── */
    --z-base:         1;
    --z-raised:      10;
    --z-floating:    80;
    --z-nav:        100;
    --z-drawer:     105;
    --z-drawer-top: 115;  /* close button + above-drawer chrome */
    --z-popup:      200;
    --z-popup-top:  210;  /* popup close button */
    --z-toast:      300;
    --z-cursor:     999;

    /* Motion */
    --ease-out:    cubic-bezier(0.16, 1, 0.3, 1);
    --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);
    --t-fast: 180ms;
    --t-base: 320ms;
    --t-slow: 600ms;
}

/* ─── RESET + RESPONSIVE FOUNDATION ──────────────────────────────────────── */
*, *::before, *::after {
    box-sizing: border-box;
    /* Prevent any element from being wider than its parent — kills horizontal overflow */
    min-width: 0;
}
* { margin: 0; padding: 0; }

html {
    -webkit-text-size-adjust: 100%;
    scroll-behavior: smooth;
    scroll-padding-top: var(--nav-h);
    -webkit-overflow-scrolling: touch;
    /* Guarantee no horizontal scroll bug from off-canvas children */
    overflow-x: hidden;
    /* Use dynamic viewport units when available (responds to Safari URL-bar) */
    height: 100%;
}

body {
    font-family: var(--font-body);
    font-size: var(--fs-base);
    line-height: var(--lh-base);
    color: var(--slate-900);
    background: var(--pure);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
    overflow-x: hidden;
    overflow-x: clip;       /* preferred — doesn't kill scroll containers */
    -webkit-tap-highlight-color: transparent;
    min-height: 100vh;
    min-height: 100dvh;
    width: 100%;
    max-width: 100vw;
    position: relative;
}

/* Lock to viewport-width — prevents accidental horizontal overflow from
   absolutely-positioned decorative SVGs / glows that extend past viewport edges. */
main, section, header, footer, .container, .container-md, .container-sm, .container-xl {
    max-width: 100%;
}

/* Media defaults — never let images or videos exceed their container */
img, picture, video, canvas, svg, iframe {
    max-width: 100%;
}
img, picture, video, canvas, svg { height: auto; }

/* Touch-friendly tap targets on phones (Apple HIG: 44px / Material: 48px) */
@media (hover: none) and (pointer: coarse) {
    a, button, [role="button"], input[type="submit"], input[type="button"] {
        -webkit-tap-highlight-color: rgba(21, 128, 61, 0.08);
    }
}

img, picture, svg, video { display: block; max-width: 100%; height: auto; }
button { cursor: pointer; background: none; border: 0; font: inherit; color: inherit; }
a { color: inherit; text-decoration: none; transition: color var(--t-fast) var(--ease-out); }
ul, ol { list-style: none; }
input, textarea, select, button { font: inherit; color: inherit; }
::selection { background: var(--eco-glow); color: var(--ink); }

.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;
}

.skip-link {
    position: absolute; top: -40px; left: 0;
    background: var(--eco-deep); color: var(--pure);
    padding: var(--space-2) var(--space-4);
    z-index: 9999; transition: top var(--t-fast);
}
.skip-link:focus { top: 0; }

/* ─── TYPOGRAPHY ──────────────────────────────────────────────────────────── */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-body);
    font-weight: 700;
    line-height: var(--lh-tight);
    letter-spacing: var(--tracking-tight);
    color: var(--ink);
}

.display {
    font-family: var(--font-display);
    font-weight: 500;
    letter-spacing: -0.015em;
    line-height: 1.05;
}

.eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-size: 0.7rem;
    font-weight: 700;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--eco-primary);
}
.eyebrow::before {
    content: '';
    width: 24px; height: 1px;
    background: currentColor;
    opacity: 0.6;
}
.eyebrow.is-light { color: var(--eco-glow); }
.eyebrow.is-gold  { color: var(--gold); }

.lede {
    font-size: var(--fs-lg);
    line-height: var(--lh-base);
    color: var(--slate-500);
    max-width: 60ch;
}

/* ─── LAYOUT ──────────────────────────────────────────────────────────────── */
.container { width: 100%; max-width: var(--maxw); margin-inline: auto; padding-inline: clamp(1rem, 3vw, 1.5rem); }
.container-md { width: 100%; max-width: var(--maxw-md); margin-inline: auto; padding-inline: clamp(1rem, 3vw, 1.5rem); }
.container-sm { width: 100%; max-width: var(--maxw-sm); margin-inline: auto; padding-inline: clamp(1rem, 3vw, 1.5rem); }
.container-xl { width: 100%; max-width: var(--maxw-xl); margin-inline: auto; padding-inline: clamp(1rem, 3vw, 1.5rem); }

/* Ultra-wide: increase max-widths slightly so layout doesn't feel cramped on 4K */
@media (min-width: 1680px) {
    :root { --maxw: 1440px; --maxw-xl: 1680px; }
}

.section { padding-block: clamp(4rem, 8vw, 7rem); }
.section-tight { padding-block: clamp(3rem, 5vw, 4.5rem); }

.section-header { text-align: center; max-width: 720px; margin: 0 auto var(--space-12); }
.section-header.is-left { text-align: left; margin-inline: 0; }
.section-header h2 {
    font-size: clamp(2rem, 3.5vw + 0.5rem, 3.5rem);
    margin-block: var(--space-3) var(--space-4);
    letter-spacing: var(--tracking-tight);
}
.section-header p { color: var(--slate-500); font-size: var(--fs-md); }

/* ─── GRID SYSTEM (mobile-first) ──────────────────────────────────────────
   Default: single column on mobile. Scales up at md/lg breakpoints. */
.grid { display: grid; gap: var(--space-6); grid-template-columns: 1fr; }
.grid-2, .grid-3, .grid-4, .grid-split, .grid-aside { grid-template-columns: 1fr; }

@media (min-width: 768px) {
    .grid-2 { grid-template-columns: repeat(2, 1fr); }
    .grid-3 { grid-template-columns: repeat(2, 1fr); }
    .grid-4 { grid-template-columns: repeat(2, 1fr); }
    /* 1fr 1fr split layout (used on contact/about) */
    .grid-split { grid-template-columns: 1fr 1fr; }
    /* 1fr 2fr aside layout (used on news section) */
    .grid-aside { grid-template-columns: 1fr 2fr; }
}
@media (min-width: 1024px) {
    .grid-3 { grid-template-columns: repeat(3, 1fr); }
    .grid-4 { grid-template-columns: repeat(4, 1fr); }
}

/* ─── BUTTONS ─────────────────────────────────────────────────────────────── */
.btn {
    display: inline-flex; align-items: center; gap: var(--space-2);
    padding: 0.95rem 1.6rem;
    border-radius: var(--r-pill);
    font-size: var(--fs-sm);
    font-weight: 600;
    letter-spacing: 0.01em;
    line-height: 1;
    cursor: pointer;
    transition: all var(--t-base) var(--ease-out);
    white-space: nowrap;
    border: 1px solid transparent;
    position: relative;
    overflow: hidden;
    isolation: isolate;
}

.btn-sm  { padding: 0.7rem 1.2rem; font-size: var(--fs-xs); letter-spacing: 0.06em; text-transform: uppercase; }
.btn-lg  { padding: 1.15rem 2rem;  font-size: var(--fs-base); }
.btn-block { width: 100%; justify-content: center; }

.btn-primary {
    background: var(--grad-emerald);
    color: var(--pure);
    box-shadow: var(--shadow-glow);
}
.btn-primary::before {
    content: '';
    position: absolute; inset: 0; z-index: -1;
    background: linear-gradient(135deg, #0d3b2e, #15803d);
    opacity: 0; transition: opacity var(--t-base) var(--ease-out);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 14px 40px rgba(52,211,153,0.35); }
.btn-primary:hover::before { opacity: 1; }

.btn-outline {
    background: transparent;
    border-color: var(--eco-primary);
    color: var(--eco-primary);
}
.btn-outline:hover { background: var(--eco-primary); color: var(--pure); transform: translateY(-2px); }

.btn-ghost {
    background: var(--glass-bg-light);
    color: var(--eco-deep);
    backdrop-filter: blur(8px);
    border-color: rgba(13, 59, 46, 0.10);
}
.btn-ghost:hover { background: var(--pure); transform: translateY(-2px); box-shadow: var(--shadow-md); }

.btn-light {
    background: var(--pure);
    color: var(--eco-deep);
    box-shadow: var(--shadow);
}
.btn-light:hover { background: var(--cream); transform: translateY(-2px); box-shadow: var(--shadow-lg); }

.btn-gold {
    background: linear-gradient(135deg, var(--gold) 0%, var(--gold-soft) 100%);
    color: var(--ink);
    box-shadow: var(--shadow-gold);
}
.btn-gold:hover { transform: translateY(-2px); box-shadow: 0 14px 40px rgba(212,175,55,0.40); }

.btn-link {
    padding: 0; border-radius: 0;
    color: var(--eco-primary);
    border-bottom: 1px solid currentColor;
    padding-bottom: 2px;
}
.btn-link:hover { color: var(--eco-bright); transform: translateX(4px); }

.btn:disabled, .btn[aria-disabled="true"] {
    opacity: 0.55; pointer-events: none;
}

/* ─── FORMS ───────────────────────────────────────────────────────────────── */
.form { display: grid; gap: var(--space-4); }
/* form-row is mobile-first (1 col) — 2 cols at md+ handled in responsive.css */
.form-row { display: grid; gap: var(--space-4); }

.form input,
.form select,
.form textarea {
    width: 100%;
    padding: 0.95rem 1.1rem;
    background: var(--pure);
    border: 1px solid var(--slate-200);
    border-radius: var(--r-md);
    font-size: 16px; /* prevent iOS zoom on focus */
    color: var(--slate-900);
    transition: border-color var(--t-fast), box-shadow var(--t-fast), background var(--t-fast);
    font-family: inherit;
}
@media (min-width: 768px) {
    .form input, .form select, .form textarea { font-size: var(--fs-sm); }
}
.form input::placeholder,
.form textarea::placeholder { color: var(--slate-400); }

.form input:focus,
.form select:focus,
.form textarea:focus {
    outline: none;
    border-color: var(--eco-primary);
    box-shadow: 0 0 0 4px rgba(21, 128, 61, 0.08);
    background: var(--pure);
}

.form textarea { resize: vertical; min-height: 110px; }

.form label {
    display: block;
    font-size: var(--fs-xs);
    font-weight: 600;
    color: var(--slate-700);
    margin-bottom: var(--space-2);
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

.form-msg {
    font-size: var(--fs-sm);
    margin-top: var(--space-2);
    min-height: 1.4em;
}
.form-msg.is-success { color: var(--success); }
.form-msg.is-error   { color: var(--danger); }

/* ─── REVEAL ANIMATIONS ───────────────────────────────────────────────────── */
[data-reveal] {
    opacity: 0;
    transform: translateY(28px);
    transition: opacity 0.9s var(--ease-out), transform 0.9s var(--ease-out);
    will-change: opacity, transform;
}
[data-reveal].is-visible { opacity: 1; transform: translateY(0); }

[data-reveal="left"]  { transform: translateX(-40px); }
[data-reveal="right"] { transform: translateX(40px); }
[data-reveal="left"].is-visible,
[data-reveal="right"].is-visible { transform: translateX(0); }

[data-reveal-delay="100"] { transition-delay: 0.10s; }
[data-reveal-delay="200"] { transition-delay: 0.20s; }
[data-reveal-delay="300"] { transition-delay: 0.30s; }
[data-reveal-delay="400"] { transition-delay: 0.40s; }
[data-reveal-delay="500"] { transition-delay: 0.50s; }

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
    html { scroll-behavior: auto; }
}

/* ─── KEYFRAMES ───────────────────────────────────────────────────────────── */
@keyframes glow-pulse {
    0%, 100% { opacity: 0.35; transform: scale(1); }
    50%      { opacity: 0.6;  transform: scale(1.08); }
}
@keyframes float-slow {
    0%, 100% { transform: translateY(0); }
    50%      { transform: translateY(-12px); }
}
@keyframes shimmer {
    0%   { background-position: -200% center; }
    100% { background-position: 200% center; }
}
@keyframes marquee {
    0%   { transform: translateX(0); }
    100% { transform: translateX(-50%); }
}
@keyframes fade-up {
    from { opacity: 0; transform: translateY(20px); }
    to   { opacity: 1; transform: translateY(0); }
}

/* ─── UTILS ───────────────────────────────────────────────────────────────── */
.text-center { text-align: center; }
.text-left   { text-align: left; }
.flex { display: flex; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-2 { gap: var(--space-2); }
.gap-3 { gap: var(--space-3); }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }
.gap-8 { gap: var(--space-8); }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mt-8 { margin-top: var(--space-8); }
.mt-10 { margin-top: var(--space-10); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }
.mb-8 { margin-bottom: var(--space-8); }
.mb-10 { margin-bottom: var(--space-10); }
.text-emerald { color: var(--eco-primary); }
.text-gold { color: var(--gold); }
.text-light { color: var(--slate-500); }
.bg-cream { background: var(--cream); }
.bg-dark  { background: var(--eco-ink); color: var(--pure); }