/* ============================================================
   DESIGN TOKENS — students.iiitr.ac.in  (Revamp 2026)
   Institutional · flat · black + blue · ZERO gradients.
   One design system, one place.
   ============================================================ */

:root {
	/* --- Canvas & surfaces (blue-black, flat) --- */
	--bg: #05070e;
	--bg-2: #090c16;
	--surface: #0e1220;
	--surface-2: #141a2a;
	--surface-3: #1b2234;

	/* --- Hairlines --- */
	--border: rgba(255, 255, 255, 0.09);
	--border-strong: rgba(255, 255, 255, 0.18);

	/* --- Ink --- */
	--text: #eaeef7;
	--text-muted: #9aa4b8;
	--text-dim: #616a7e;
	--white: #ffffff;

	/* --- Accent: a single, solid institutional blue --- */
	--blue: #2f6dff;
	--blue-bright: #5688ff;
	--blue-deep: #1b4ed8;
	--blue-tint: rgba(47, 109, 255, 0.12);
	--blue-line: rgba(47, 109, 255, 0.4);

	/* --- Shadow (flat black only, no colored glow) --- */
	--shadow-soft: 0 8px 24px rgba(0, 0, 0, 0.35);
	--shadow: 0 22px 50px rgba(0, 0, 0, 0.5);
	--shadow-card: 0 18px 40px rgba(0, 0, 0, 0.45);

	/* --- Radius --- */
	--radius-sm: 8px;
	--radius: 14px;
	--radius-lg: 20px;
	--radius-pill: 999px;

	/* --- Spacing --- */
	--space-1: 8px;
	--space-2: 16px;
	--space-3: 24px;
	--space-4: 40px;
	--space-5: 72px;
	--section-gap-y: 120px;

	/* --- Type --- */
	--font-sans: 'Plain', system-ui, -apple-system, 'Segoe UI', sans-serif;
	--fs-hero: clamp(2.6rem, 6vw, 5rem);
	--fs-h2: clamp(1.9rem, 3.8vw, 2.9rem);
	--fs-h3: clamp(1.25rem, 2vw, 1.55rem);
	--fs-body: 1.06rem;
	--fs-small: 0.9rem;
	--fs-eyebrow: 0.78rem;

	/* --- Motion --- */
	--ease: cubic-bezier(0.22, 1, 0.36, 1);
	--reveal-duration: 750ms;
	--reveal-distance: 28px;

	/* --- Layout --- */
	--maxw: 1220px;
	--nav-h: 72px;
}

/* ---------- Reset / base ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

html {
	scroll-behavior: smooth;
	scroll-padding-top: calc(var(--nav-h) + 20px);
	-webkit-text-size-adjust: 100%;
}

body {
	margin: 0;
	background: var(--bg);
	color: var(--text);
	font-family: var(--font-sans);
	font-size: var(--fs-body);
	line-height: 1.65;
	-webkit-font-smoothing: antialiased;
	text-rendering: optimizeLegibility;
	overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
	line-height: 1.08;
	letter-spacing: -0.02em;
	color: var(--white);
	margin: 0 0 0.5em;
	font-weight: 700;
	text-wrap: balance;
}

p { margin: 0 0 1em; color: var(--text-muted); }

a {
	color: var(--blue-bright);
	text-decoration: none;
	transition: color 0.2s var(--ease);
}
a:hover { color: var(--white); }

img { max-width: 100%; display: block; }

/* ---------- Helpers ---------- */
.shell {
	width: 100%;
	max-width: var(--maxw);
	margin-inline: auto;
	padding-inline: clamp(20px, 5vw, 44px);
}

.section {
	padding-block: var(--section-gap-y);
	position: relative;
}

.eyebrow {
	display: inline-flex;
	align-items: center;
	gap: 10px;
	font-size: var(--fs-eyebrow);
	font-weight: 600;
	letter-spacing: 0.2em;
	text-transform: uppercase;
	color: var(--blue-bright);
	margin-bottom: 18px;
}
.eyebrow::before {
	content: '';
	width: 22px;
	height: 2px;
	background: var(--blue);
}

/* Buttons — solid, flat */
.btn-ds {
	display: inline-flex;
	align-items: center;
	gap: 10px;
	padding: 14px 28px;
	border-radius: var(--radius-pill);
	font-weight: 600;
	font-size: 0.96rem;
	border: 1px solid transparent;
	cursor: pointer;
	transition: transform 0.25s var(--ease), background 0.25s var(--ease), border-color 0.25s var(--ease);
}
.btn-ds--primary {
	background: var(--blue);
	color: #fff;
}
.btn-ds--primary:hover {
	background: var(--blue-deep);
	color: #fff;
	transform: translateY(-2px);
}
.btn-ds--ghost {
	background: transparent;
	border-color: var(--border-strong);
	color: var(--text);
}
.btn-ds--ghost:hover {
	border-color: var(--blue);
	color: #fff;
	transform: translateY(-2px);
}

/* ---------- Scroll reveal ---------- */
[data-reveal],
[data-aos] {
	opacity: 0;
	transform: translateY(var(--reveal-distance));
	transition: opacity var(--reveal-duration) var(--ease),
		transform var(--reveal-duration) var(--ease);
	will-change: opacity, transform;
}
[data-reveal].is-visible,
[data-aos].is-visible { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
	html { scroll-behavior: auto; }
	[data-reveal], [data-aos] { opacity: 1; transform: none; transition: none; }
	* { animation-duration: 0.001ms !important; }
}