/* ================================================
   DEVOPS-IELTS — Premium Design System v3
   Professional EdTech Platform Aesthetic
   ================================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600&family=Poppins:wght@700;800;900&display=swap');

:root {
    /* Core Brand */
    --primary:        #6366f1;
    --primary-dark:   #4f46e5;
    --primary-light:  #a5b4fc;
    --secondary:      #8b5cf6;
    --accent-green:   #10b981;
    --accent-orange:  #f59e0b;

    /* Neutral Scale */
    --text-main:      #0f172a;
    --text-muted:     #64748b;
    --text-light:     #94a3b8;
    --border:         #e2e8f0;
    --bg-soft:        #f8fafc;
    --bg-white:       #ffffff;

    /* Gradients */
    --gradient-brand: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
    --gradient-subtle: linear-gradient(135deg, rgba(99,102,241,0.06) 0%, rgba(139,92,246,0.04) 100%);

    /* Shadows */
    --shadow-xs:  0 1px 2px rgba(0,0,0,0.04);
    --shadow-sm:  0 4px 6px -1px rgba(0,0,0,0.04), 0 2px 4px -1px rgba(0,0,0,0.02);
    --shadow-md:  0 10px 20px -5px rgba(0,0,0,0.06), 0 4px 8px -2px rgba(0,0,0,0.03);
    --shadow-lg:  0 20px 35px -10px rgba(0,0,0,0.08), 0 8px 16px -4px rgba(0,0,0,0.04);
    --shadow-brand: 0 12px 28px -6px rgba(99,102,241,0.35);

    /* Radii */
    --r-sm:   0.5rem;
    --r-md:   0.875rem;
    --r-lg:   1.25rem;
    --r-xl:   1.75rem;
    --r-full: 9999px;

    /* Typography */
    --font-sans:    'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-display: 'Poppins', sans-serif;

    /* Transitions */
    --ease-out: all 0.3s cubic-bezier(0.22, 1, 0.36, 1);
    --ease-spring: all 0.45s cubic-bezier(0.34, 1.56, 0.64, 1);
}

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

html { scroll-behavior: smooth; overflow-y: scroll; }

body {
    font-family: var(--font-sans);
    background: var(--bg-soft);
    color: var(--text-muted);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    color: var(--text-main);
    line-height: 1.2;
    font-weight: 800;
}

a { text-decoration: none; color: inherit; transition: var(--ease-out); }
ul { list-style: none; }
img { max-width: 100%; height: auto; display: block; }

/* ── Layout ── */
.container {
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* ── Navbar ── */
.navbar {
    background: rgba(255, 255, 255, 0.88);
    backdrop-filter: blur(16px) saturate(180%);
    -webkit-backdrop-filter: blur(16px) saturate(180%);
    border-bottom: 1px solid rgba(226, 232, 240, 0.8);
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 100;
    padding: 1rem 0;
    transition: var(--ease-out);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

/* ── Logo ── */
.logo {
    display: flex;
    flex: 1;
    align-items: center;
    gap: 0.625rem;
    font-family: var(--font-display);
    font-weight: 900;
    font-size: 1.35rem;
    letter-spacing: -0.03em;
    color: var(--text-main);
}

.logo .text-primary { color: var(--primary); }

.logo span {
    font-family: var(--font-display);
    font-weight: 900;
}

/* ── Nav Links ── */
.nav-links {
    display: flex;
    gap: 0.25rem;
    align-items: center;
}

.nav-links a {
    font-weight: 500;
    font-size: 0.9rem;
    color: var(--text-muted);
    padding: 0.5rem 0.875rem;
    border-radius: var(--r-full);
    transition: var(--ease-out);
}

.nav-links a:hover {
    color: var(--text-main);
    background: rgba(15, 23, 42, 0.05);
}

.nav-links a.active {
    color: var(--primary);
    background: rgba(99, 102, 241, 0.08);
    font-weight: 600;
}

.nav-right {
    display: flex;
    flex: 1;
    justify-content: flex-end;
    align-items: center;
    gap: 1rem;
}

/* ── Buttons ── */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.625rem 1.375rem;
    border-radius: var(--r-full);
    font-family: var(--font-sans);
    font-weight: 600;
    font-size: 0.9rem;
    border: none;
    cursor: pointer;
    transition: var(--ease-spring);
    white-space: nowrap;
    line-height: 1;
}

.btn-primary {
    background: var(--gradient-brand);
    color: white;
    box-shadow: var(--shadow-brand);
}

.btn-primary:hover {
    transform: translateY(-2px) scale(1.02);
    box-shadow: 0 16px 32px -8px rgba(99, 102, 241, 0.45);
}

.btn-primary:active { transform: scale(0.98); }

.btn-outline {
    background: white;
    border: 1.5px solid var(--border);
    color: var(--text-main);
    box-shadow: var(--shadow-xs);
}

.btn-outline:hover {
    border-color: var(--primary);
    color: var(--primary);
    background: rgba(99, 102, 241, 0.04);
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
}

.btn-lg {
    padding: 0.875rem 2.5rem;
    font-size: 1rem;
    border-radius: var(--r-full);
}

/* ── Language Switcher ── */
.lang-switcher {
    display: flex;
    background: var(--bg-soft);
    border: 1px solid var(--border);
    padding: 3px;
    border-radius: var(--r-full);
    gap: 2px;
}

.lang-btn {
    border: none;
    background: transparent;
    padding: 0.35rem 0.8rem;
    border-radius: var(--r-full);
    font-size: 0.75rem;
    font-weight: 700;
    color: var(--text-muted);
    cursor: pointer;
    transition: var(--ease-out);
    letter-spacing: 0.03em;
}

.lang-btn.active {
    background: var(--primary);
    color: white;
    box-shadow: 0 2px 8px rgba(99, 102, 241, 0.35);
}

/* ── Mobile Menu Btn ── */
.mobile-menu-btn {
    display: none;
    background: transparent;
    border: 1.5px solid var(--border);
    cursor: pointer;
    color: var(--text-main);
    padding: 0.5rem;
    border-radius: var(--r-md);
    position: relative;
    z-index: 101;
    transition: var(--ease-out);
}

.mobile-menu-btn:hover { background: var(--bg-soft); }

/* ── Mobile Menu ── */
.mobile-menu {
    display: flex;
    position: fixed;
    top: 0;
    right: -110%;
    width: 100%;
    max-width: 360px;
    height: 100dvh;
    background: white;
    box-shadow: -20px 0 50px -10px rgba(0,0,0,0.1);
    padding: 5.5rem 1.5rem 2rem;
    flex-direction: column;
    gap: 0.5rem;
    z-index: 90;
    transition: right 0.4s cubic-bezier(0.22, 1, 0.36, 1);
    border-left: 1px solid var(--border);
}

.mobile-menu.active { right: 0; }

.mobile-menu a {
    padding: 1rem 1.25rem;
    border-radius: var(--r-lg);
    font-weight: 600;
    color: var(--text-muted);
    font-size: 1rem;
    transition: var(--ease-out);
}

.mobile-menu a:hover,
.mobile-menu a.active {
    background: rgba(99, 102, 241, 0.07);
    color: var(--primary);
}

.mobile-menu .btn-primary {
    text-align: center;
    margin-top: 0.5rem;
    border-radius: var(--r-xl);
    padding: 0.875rem;
}

.mobile-menu .lang-switcher {
    margin-top: auto;
    justify-content: center;
    align-self: stretch;
}

/* ── Section ── */
.section { padding: 7rem 0; }

/* ── Hero ── */
.hero {
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background:
        radial-gradient(ellipse 80% 60% at 20% 20%, rgba(99,102,241,0.12) 0%, transparent 60%),
        radial-gradient(ellipse 60% 80% at 80% 80%, rgba(139,92,246,0.09) 0%, transparent 60%);
    z-index: 0;
}

.hero > * { position: relative; z-index: 1; }

/* ── Floating Badge ── */
.badge-pill {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: white;
    color: var(--primary);
    padding: 0.45rem 1.1rem;
    border-radius: var(--r-full);
    font-size: 0.85rem;
    font-weight: 600;
    box-shadow: var(--shadow-sm);
    border: 1px solid rgba(99,102,241,0.15);
    animation: float-y 5s ease-in-out infinite;
}

@keyframes float-y {
    0%, 100% { transform: translateY(0); }
    50%       { transform: translateY(-6px); }
}

/* ── Feature Cards ── */
.card {
    background: var(--bg-white);
    border: 1px solid var(--border);
    border-radius: var(--r-xl);
    padding: 2.5rem;
    transition: var(--ease-spring);
}

.card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: rgba(99,102,241,0.2);
}

.icon-box {
    width: 3.5rem;
    height: 3.5rem;
    border-radius: var(--r-md);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.5rem;
    transition: var(--ease-spring);
}

.card:hover .icon-box {
    transform: scale(1.1) rotate(-5deg);
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.75rem;
}

/* ── Section Header ── */
.section-header {
    text-align: center;
    max-width: 640px;
    margin: 0 auto 4.5rem;
}

.section-label {
    display: inline-block;
    color: var(--primary);
    font-weight: 700;
    font-size: 0.78rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    margin-bottom: 1rem;
    background: rgba(99,102,241,0.08);
    padding: 0.3rem 0.9rem;
    border-radius: var(--r-full);
}

/* ── Animate in on scroll ── */
@keyframes fade-up {
    from { opacity: 0; transform: translateY(28px); }
    to   { opacity: 1; transform: translateY(0); }
}

.animate-up {
    animation: fade-up 0.6s var(--ease-out) both;
}
.animate-up:nth-child(2) { animation-delay: 0.1s; }
.animate-up:nth-child(3) { animation-delay: 0.2s; }

/* ── Footer ── */
.footer {
    background: white;
    border-top: 1px solid var(--border);
    padding: 4rem 0 2.5rem;
}

.footer-content {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    gap: 3rem;
    margin-bottom: 3.5rem;
}

/* ── Learning Path (learn.html) ── */
.learning-path { position: relative; max-width: 800px; margin: 4rem auto; padding: 2rem 0; }

.learning-path::before {
    content: '';
    position: absolute;
    top: 50px;
    bottom: 50px;
    left: 50%;
    transform: translateX(-50%);
    width: 4px;
    background: var(--border);
    border-radius: 100px;
    z-index: 0;
}

.path-node-wrapper {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    margin-bottom: 4rem;
    position: relative;
    z-index: 1;
}

.path-node-wrapper:nth-child(odd) .node-content  { flex-direction: row-reverse; text-align: right; padding-right: 3rem; }
.path-node-wrapper:nth-child(even) .node-content { flex-direction: row; text-align: left; padding-left: 3rem; margin-left: auto; }

.node-content {
    width: 50%;
    display: flex;
    align-items: center;
    gap: 2rem;
    text-decoration: none;
}

.node-bubble {
    width: 90px;
    height: 90px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: white;
    box-shadow: var(--shadow-md);
    border: 3px solid white;
    transition: var(--ease-spring);
    flex-shrink: 0;
}

.node-content:hover .node-bubble {
    transform: scale(1.12) translateY(-6px);
    box-shadow: var(--shadow-lg);
}

.node-icon-wrapper {
    width: 58px;
    height: 58px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
}

.node-info h3 { font-size: 1.4rem; margin-bottom: 0.4rem; }
.node-info p  { font-size: 0.95rem; color: var(--text-muted); }

.bg-blue   { background: #3b82f6; }
.bg-green  { background: #10b981; }
.bg-purple { background: #8b5cf6; }
.bg-orange { background: #f59e0b; }

/* ── Responsive ── */
@media (max-width: 1024px) {
    .hero-content { gap: 3rem; }
}

@media (max-width: 768px) {
    .nav-links,
    .nav-right .btn-primary,
    .nav-right .lang-switcher { display: none; }

    .mobile-menu-btn {
        display: flex;
        align-items: center;
        justify-content: center;
    }

    .container { padding: 0 1.25rem; }
    .section    { padding: 5rem 0; }

    .learning-path::before { left: 50px; }

    .path-node-wrapper { justify-content: flex-start; margin-bottom: 2.5rem; }

    .node-content,
    .path-node-wrapper:nth-child(even) .node-content,
    .path-node-wrapper:nth-child(odd) .node-content {
        width: 100%;
        flex-direction: row;
        text-align: left;
        padding-left: 0;
        padding-right: 0;
        margin-left: 0;
    }
}

@media (max-width: 640px) {
    .section-header h2 { font-size: 2rem; }
    .btn-lg { padding: 0.875rem 2rem; font-size: 0.95rem; }
}