:root {
    --bg-deep: #0a0f1e;
    --bg-main: #0f172a;
    --bg-card: #1e293b;
    --bg-card2: #162032;
    --bg-hover: #243447;
    --accent: #38bdf8;
    --accent2: #818cf8;
    --success: #22c55e;
    --warning: #f59e0b;
    --danger: #f43f5e;
    --text-main: #e2e8f0;
    --text-muted: #94a3b8;
    --text-dim: #64748b;
    --border: rgba(56, 189, 248, 0.15);
    --glow: rgba(56, 189, 248, 0.25);
    --radius: 16px;
    --radius-sm: 10px;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Space Grotesk', sans-serif;
    background: var(--bg-main);
    color: var(--text-main);
    line-height: 1.75;
    overflow-x: hidden;
}

::-webkit-scrollbar {
    width: 6px;
}

::-webkit-scrollbar-track {
    background: var(--bg-deep);
}

::-webkit-scrollbar-thumb {
    background: var(--accent);
    border-radius: 3px;
}

body::before {
    content: '';
    position: fixed;
    inset: 0;
    z-index: 0;
    background-image:
        linear-gradient(rgba(56, 189, 248, 0.04) 1px, transparent 1px),
        linear-gradient(90deg, rgba(56, 189, 248, 0.04) 1px, transparent 1px);
    background-size: 40px 40px;
    pointer-events: none;
}

.bg-orb {
    position: fixed;
    border-radius: 50%;
    filter: blur(120px);
    opacity: 0.18;
    pointer-events: none;
    z-index: 0;
}

.bg-orb-1 {
    width: 600px;
    height: 600px;
    background: #818cf8;
    top: -200px;
    left: -200px;
}

.bg-orb-2 {
    width: 500px;
    height: 500px;
    background: #38bdf8;
    bottom: -200px;
    right: -200px;
}

.bg-orb-3 {
    width: 300px;
    height: 300px;
    background: #f59e0b;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

/* NAVBAR */
.course-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(10, 15, 30, 0.85);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    padding: 14px 0;
}

.course-nav .brand {
    font-family: 'Syne', sans-serif;
    font-weight: 800;
    font-size: 1.1rem;
    color: var(--accent);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 10px;
}

.course-nav .brand .brand-icon {
    width: 34px;
    height: 34px;
    background: linear-gradient(135deg, #818cf8, #38bdf8);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
    color: #fff;
}

.chapter-badge {
    background: linear-gradient(135deg, #818cf8, #38bdf8);
    color: #fff;
    font-size: 0.7rem;
    font-weight: 700;
    padding: 4px 12px;
    border-radius: 20px;
    letter-spacing: 1px;
}

/* HERO */
.hero-section {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 120px 0 80px;
    position: relative;
    overflow: hidden;
}

.chapter-number-pill {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: rgba(129, 140, 248, 0.1);
    border: 1px solid rgba(129, 140, 248, 0.3);
    color: var(--accent2);
    font-weight: 700;
    letter-spacing: 2px;
    font-size: 0.75rem;
    text-transform: uppercase;
    padding: 6px 18px;
    border-radius: 30px;
    margin-bottom: 24px;
}

.hero-title {
    font-family: 'Syne', sans-serif;
    font-size: clamp(2.6rem, 6vw, 5rem);
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 24px;
}

.hero-title .gradient-text {
    background: linear-gradient(135deg, #818cf8 0%, #38bdf8 50%, #f59e0b 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-desc {
    font-size: 1.1rem;
    color: var(--text-muted);
    max-width: 560px;
    margin-bottom: 40px;
}

.hero-code-window {
    background: #0d1b2a;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: 0 40px 80px rgba(0, 0, 0, 0.5), 0 0 60px rgba(129, 140, 248, 0.1);
}

.window-bar {
    background: #1a2535;
    padding: 12px 16px;
    display: flex;
    align-items: center;
    gap: 8px;
    border-bottom: 1px solid var(--border);
}

.dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
}

.dot-r {
    background: #f43f5e;
}

.dot-y {
    background: #f59e0b;
}

.dot-g {
    background: #22c55e;
}

.window-title {
    margin-left: 8px;
    font-size: 0.75rem;
    color: var(--text-dim);
    font-family: 'Fira Code', monospace;
}

.window-body {
    padding: 24px;
    font-family: 'Fira Code', monospace;
    font-size: 0.85rem;
}

.code-line {
    display: flex;
    margin-bottom: 8px;
}

.ln {
    color: #2d4a6b;
    margin-right: 20px;
    user-select: none;
    min-width: 20px;
    text-align: right;
}

.kw {
    color: #c792ea;
}

.fn {
    color: #82aaff;
}

.str {
    color: #c3e88d;
}

.cm {
    color: #546e7a;
    font-style: italic;
}

.op {
    color: #89ddff;
}

.num {
    color: #f78c6c;
}

.ot {
    color: #e2e8f0;
}

.floating-badge {
    position: absolute;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 12px 18px;
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 0.82rem;
    font-weight: 600;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
    animation: floatBadge 3s ease-in-out infinite;
}

.floating-badge-1 {
    top: -20px;
    right: -20px;
    animation-delay: 0s;
}

.floating-badge-2 {
    bottom: -20px;
    left: -20px;
    animation-delay: 1.5s;
}

@keyframes floatBadge {

    0%,
    100% {
        transform: translateY(0)
    }

    50% {
        transform: translateY(-8px)
    }
}

/* OBJECTIVES */
.obj-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 16px;
}

.obj-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 18px 20px;
    display: flex;
    align-items: flex-start;
    gap: 14px;
    transition: all 0.3s;
}

.obj-card:hover {
    border-color: var(--accent);
    transform: translateY(-4px);
    box-shadow: 0 12px 30px rgba(56, 189, 248, 0.1);
}

.obj-icon {
    width: 38px;
    height: 38px;
    min-width: 38px;
    background: linear-gradient(135deg, rgba(129, 140, 248, 0.2), rgba(56, 189, 248, 0.2));
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent2);
    font-size: 0.9rem;
}

/* SECTION HEADERS */
.section-label {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 0.72rem;
    font-weight: 700;
    letter-spacing: 2px;
    text-transform: uppercase;
    color: var(--accent2);
    background: rgba(129, 140, 248, 0.1);
    border: 1px solid rgba(129, 140, 248, 0.2);
    padding: 5px 14px;
    border-radius: 20px;
    margin-bottom: 14px;
}

.section-title {
    font-family: 'Syne', sans-serif;
    font-size: clamp(1.8rem, 4vw, 2.8rem);
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 16px;
}

.section-sub {
    color: var(--text-muted);
    font-size: 1rem;
    max-width: 600px;
}

.section-divider {
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, #818cf8, #38bdf8);
    border-radius: 2px;
    margin: 20px 0;
}

/* CARDS */
.glass-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px;
    transition: all 0.35s;
}

.glass-card:hover {
    border-color: rgba(129, 140, 248, 0.4);
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.3), 0 0 30px rgba(129, 140, 248, 0.07);
    transform: translateY(-5px);
}

.info-card {
    background: var(--bg-card2);
    border-radius: var(--radius);
    border: 1px solid var(--border);
    padding: 24px;
    height: 100%;
    transition: all 0.3s;
}

.info-card:hover {
    border-color: rgba(129, 140, 248, 0.4);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    transform: translateY(-4px);
}

.info-card .card-icon {
    width: 52px;
    height: 52px;
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.3rem;
    margin-bottom: 18px;
}

/* CALLOUTS */
.callout {
    border-radius: var(--radius-sm);
    padding: 18px 22px;
    display: flex;
    gap: 14px;
    align-items: flex-start;
    margin: 20px 0;
}

.callout-icon {
    font-size: 1.2rem;
    margin-top: 2px;
    min-width: 22px;
}

.callout-blue {
    background: rgba(56, 189, 248, 0.08);
    border-left: 4px solid #38bdf8;
}

.callout-green {
    background: rgba(34, 197, 94, 0.08);
    border-left: 4px solid #22c55e;
}

.callout-warn {
    background: rgba(245, 158, 11, 0.08);
    border-left: 4px solid #f59e0b;
}

.callout-red {
    background: rgba(244, 63, 94, 0.08);
    border-left: 4px solid #f43f5e;
}

.callout-purple {
    background: rgba(129, 140, 248, 0.08);
    border-left: 4px solid #818cf8;
}

.callout .callout-title {
    font-weight: 700;
    font-size: 0.88rem;
    letter-spacing: 0.5px;
}

.callout .callout-body {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-top: 4px;
}

/* KEYWORD HIGHLIGHT */
.kw-highlight {
    background: rgba(56, 189, 248, 0.12);
    color: var(--accent);
    padding: 1px 8px;
    border-radius: 5px;
    font-family: 'Fira Code', monospace;
    font-size: 0.88em;
    font-weight: 500;
}

.kw-green {
    background: rgba(34, 197, 94, 0.12);
    color: #22c55e;
    padding: 1px 8px;
    border-radius: 5px;
    font-family: 'Fira Code', monospace;
    font-size: 0.88em;
}

.kw-warn {
    background: rgba(245, 158, 11, 0.12);
    color: #f59e0b;
    padding: 1px 8px;
    border-radius: 5px;
    font-family: 'Fira Code', monospace;
    font-size: 0.88em;
}

.kw-purple {
    background: rgba(129, 140, 248, 0.12);
    color: #818cf8;
    padding: 1px 8px;
    border-radius: 5px;
    font-family: 'Fira Code', monospace;
    font-size: 0.88em;
}

.kw-red {
    background: rgba(244, 63, 94, 0.12);
    color: #f43f5e;
    padding: 1px 8px;
    border-radius: 5px;
    font-family: 'Fira Code', monospace;
    font-size: 0.88em;
}

/* CONCEPT CARDS */
.concept-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    transition: all 0.35s;
}

.concept-card:hover {
    border-color: rgba(129, 140, 248, 0.4);
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.3);
    transform: translateY(-5px);
}

.concept-header {
    padding: 20px 24px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    gap: 14px;
}

.concept-num {
    width: 36px;
    height: 36px;
    border-radius: 10px;
    background: linear-gradient(135deg, #818cf8, #38bdf8);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    font-size: 0.85rem;
    color: #fff;
}

.concept-body {
    padding: 24px;
}

/* CODE BLOCKS */
.code-block {
    background: #0d1b2a;
    border: 1px solid rgba(129, 140, 248, 0.15);
    border-radius: var(--radius-sm);
    overflow: hidden;
    margin: 16px 0;
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.3);
}

.code-topbar {
    background: #1a2535;
    padding: 10px 16px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid rgba(129, 140, 248, 0.1);
}

.code-lang {
    font-size: 0.72rem;
    font-weight: 700;
    letter-spacing: 1px;
    color: var(--accent2);
    text-transform: uppercase;
    display: flex;
    align-items: center;
    gap: 8px;
}

.code-dots {
    display: flex;
    gap: 6px;
}

.code-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
}

.copy-btn {
    background: rgba(129, 140, 248, 0.1);
    border: 1px solid rgba(129, 140, 248, 0.2);
    color: var(--accent2);
    font-size: 0.72rem;
    font-weight: 600;
    padding: 5px 12px;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.2s;
    font-family: 'Space Grotesk', sans-serif;
    letter-spacing: 0.5px;
}

.copy-btn:hover {
    background: rgba(129, 140, 248, 0.2);
}

.copy-btn.copied {
    background: rgba(34, 197, 94, 0.2);
    border-color: rgba(34, 197, 94, 0.3);
    color: #22c55e;
}

.code-content {
    padding: 20px 20px 20px 0;
    overflow-x: auto;
    font-family: 'Fira Code', monospace;
    font-size: 0.84rem;
    line-height: 1.8;
}

.code-row {
    display: flex;
    padding: 0 16px;
    margin: 0;
}

.code-row:hover {
    background: rgba(129, 140, 248, 0.04);
}

.line-no {
    min-width: 36px;
    color: #2d4a6b;
    text-align: right;
    padding-right: 20px;
    user-select: none;
}

.code-text {
    flex: 1;
    white-space: pre;
}

.s-kw {
    color: #c792ea;
}

.s-fn {
    color: #82aaff;
}

.s-str {
    color: #c3e88d;
}

.s-cm {
    color: #546e7a;
    font-style: italic;
}

.s-op {
    color: #89ddff;
}

.s-num {
    color: #f78c6c;
}

.s-mod {
    color: #ffcb6b;
}

.s-ot {
    color: #e2e8f0;
}

.s-bool {
    color: #f78c6c;
}

.s-none {
    color: #546e7a;
}

/* OUTPUT BOX */
.output-box {
    background: #060e1a;
    border: 1px solid rgba(34, 197, 94, 0.2);
    border-radius: var(--radius-sm);
    padding: 16px 20px;
    margin-top: 14px;
}

.output-label {
    font-size: 0.7rem;
    font-weight: 700;
    letter-spacing: 2px;
    color: #22c55e;
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    gap: 6px;
    text-transform: uppercase;
}

.output-label::before {
    content: '';
    width: 8px;
    height: 8px;
    background: #22c55e;
    border-radius: 50%;
    animation: blink 1.5s ease-in-out infinite;
}

@keyframes blink {

    0%,
    100% {
        opacity: 1
    }

    50% {
        opacity: 0.3
    }
}

.output-text {
    font-family: 'Fira Code', monospace;
    font-size: 0.84rem;
    color: #22c55e;
    line-height: 1.7;
}

/* EXAMPLE CARDS */
.example-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    transition: all 0.3s;
}

.example-card:hover {
    border-color: rgba(129, 140, 248, 0.35);
    box-shadow: 0 14px 40px rgba(0, 0, 0, 0.25);
}

.example-header {
    background: linear-gradient(135deg, rgba(129, 140, 248, 0.1), rgba(56, 189, 248, 0.1));
    padding: 18px 24px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    gap: 12px;
}

.example-num {
    width: 32px;
    height: 32px;
    background: linear-gradient(135deg, #818cf8, #38bdf8);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    font-size: 0.8rem;
    color: #fff;
}

.example-body {
    padding: 24px;
}

/* FEATURE CARDS */
.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 16px;
}

.feature-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 22px;
    transition: all 0.3s;
    text-align: center;
}

.feature-card:hover {
    border-color: rgba(129, 140, 248, 0.4);
    transform: translateY(-6px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.25);
}

.feature-card .f-icon {
    width: 54px;
    height: 54px;
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.4rem;
    margin: 0 auto 16px;
}

.feature-card h6 {
    font-weight: 700;
    margin-bottom: 8px;
}

.feature-card p {
    font-size: 0.83rem;
    color: var(--text-muted);
    margin: 0;
}

/* DATA TYPE CARDS */
.dtype-card {
    background: var(--bg-card);
    border-radius: var(--radius);
    border: 1px solid var(--border);
    overflow: hidden;
    transition: all 0.3s;
    height: 100%;
}

.dtype-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.3);
}

.dtype-header {
    padding: 18px 22px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    gap: 14px;
}

.dtype-icon {
    width: 44px;
    height: 44px;
    min-width: 44px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
}

.dtype-body {
    padding: 20px 22px;
}

.dtype-examples {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 14px;
}

.dtype-tag {
    font-family: 'Fira Code', monospace;
    font-size: 0.8rem;
    padding: 4px 10px;
    border-radius: 6px;
}

/* OPERATOR TABLE */
.op-table {
    width: 100%;
    border-collapse: collapse;
}

.op-table th,
.op-table td {
    padding: 12px 16px;
    border-bottom: 1px solid var(--border);
    text-align: left;
    font-size: 0.88rem;
}

.op-table th {
    background: rgba(129, 140, 248, 0.08);
    color: var(--accent2);
    font-weight: 700;
    font-size: 0.78rem;
    letter-spacing: 1px;
    text-transform: uppercase;
}

.op-table tbody tr {
    transition: background 0.2s;
}

.op-table tbody tr:hover {
    background: rgba(129, 140, 248, 0.04);
}

.op-table td:first-child {
    font-family: 'Fira Code', monospace;
    color: var(--accent);
    font-weight: 600;
}

.op-table td:nth-child(3) {
    font-family: 'Fira Code', monospace;
    color: #22c55e;
    font-size: 0.82rem;
}

/* FLOW CONTAINER */
.flow-container {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
    justify-content: center;
}

.flow-step {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 18px 22px;
    text-align: center;
    min-width: 120px;
    flex: 1;
    transition: all 0.3s;
    position: relative;
}

.flow-step:hover {
    border-color: var(--accent2);
    transform: translateY(-4px);
    box-shadow: 0 12px 28px rgba(129, 140, 248, 0.12);
}

.flow-step .step-icon {
    width: 44px;
    height: 44px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    margin: 0 auto 10px;
}

.flow-step .step-num {
    position: absolute;
    top: -10px;
    left: -10px;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: linear-gradient(135deg, #818cf8, #38bdf8);
    font-size: 0.7rem;
    font-weight: 800;
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
}

.flow-arrow {
    color: var(--accent2);
    font-size: 1.4rem;
    animation: arrowPulse 1.5s ease-in-out infinite;
}

@keyframes arrowPulse {

    0%,
    100% {
        opacity: 1;
        transform: translateX(0)
    }

    50% {
        opacity: 0.5;
        transform: translateX(4px)
    }
}

/* TERMINAL */
.terminal-box {
    background: #050f1a;
    border: 1px solid rgba(34, 197, 94, 0.2);
    border-radius: var(--radius-sm);
    overflow: hidden;
}

.terminal-bar {
    background: #0a1628;
    padding: 10px 16px;
    display: flex;
    align-items: center;
    gap: 8px;
    border-bottom: 1px solid rgba(34, 197, 94, 0.1);
}

.terminal-title {
    font-size: 0.72rem;
    color: var(--text-dim);
    font-family: 'Fira Code', monospace;
    margin-left: 8px;
}

.terminal-body {
    padding: 20px;
    font-family: 'Fira Code', monospace;
    font-size: 0.84rem;
    line-height: 2;
}

.t-prompt {
    color: #22c55e;
}

.t-cmd {
    color: #e2e8f0;
}

.t-output {
    color: #94a3b8;
}

/* COMPARE TABLE */
.compare-table {
    width: 100%;
    border-collapse: collapse;
}

.compare-table th,
.compare-table td {
    padding: 14px 18px;
    border-bottom: 1px solid var(--border);
    text-align: left;
    font-size: 0.9rem;
}

.compare-table th {
    background: rgba(129, 140, 248, 0.08);
    color: var(--accent2);
    font-weight: 700;
    font-size: 0.8rem;
    letter-spacing: 1px;
    text-transform: uppercase;
}

.compare-table tbody tr {
    transition: background 0.2s;
}

.compare-table tbody tr:hover {
    background: rgba(129, 140, 248, 0.04);
}

.compare-table td:first-child {
    font-family: 'Fira Code', monospace;
    color: var(--accent);
}

/* MISTAKE CARDS */
.mistake-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
}

.mistake-header {
    padding: 16px 22px;
    font-weight: 700;
    font-size: 0.9rem;
    display: flex;
    align-items: center;
    gap: 10px;
}

.mistake-wrong .mistake-header {
    background: rgba(244, 63, 94, 0.12);
    color: #f43f5e;
    border-bottom: 1px solid rgba(244, 63, 94, 0.2);
}

.mistake-right .mistake-header {
    background: rgba(34, 197, 94, 0.12);
    color: #22c55e;
    border-bottom: 1px solid rgba(34, 197, 94, 0.2);
}

.mistake-body {
    padding: 20px;
}

/* ACCORDION */
.qa-accordion .accordion-item {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm) !important;
    margin-bottom: 12px;
    overflow: hidden;
}

.qa-accordion .accordion-button {
    background: var(--bg-card);
    color: var(--text-main);
    font-weight: 600;
    font-size: 0.93rem;
    padding: 18px 22px;
    box-shadow: none;
}

.qa-accordion .accordion-button:not(.collapsed) {
    background: rgba(129, 140, 248, 0.08);
    color: var(--accent2);
}

.qa-accordion .accordion-button::after {
    filter: invert(1) brightness(0.6);
}

.qa-accordion .accordion-body {
    background: var(--bg-card2);
    color: var(--text-muted);
    font-size: 0.9rem;
    padding: 18px 22px;
    border-top: 1px solid var(--border);
}

.q-num {
    background: linear-gradient(135deg, #818cf8, #38bdf8);
    color: #fff;
    width: 26px;
    height: 26px;
    border-radius: 6px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 0.72rem;
    font-weight: 800;
    margin-right: 12px;
    flex-shrink: 0;
}

/* PRACTICE CARDS */
.practice-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    transition: all 0.3s;
    height: 100%;
}

.practice-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.3);
}

.practice-header {
    padding: 18px 22px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid var(--border);
}

.diff-badge {
    font-size: 0.68rem;
    font-weight: 800;
    padding: 4px 12px;
    border-radius: 20px;
    letter-spacing: 1px;
    text-transform: uppercase;
}

.diff-easy {
    background: rgba(34, 197, 94, 0.15);
    color: #22c55e;
    border: 1px solid rgba(34, 197, 94, 0.3);
}

.diff-medium {
    background: rgba(245, 158, 11, 0.15);
    color: #f59e0b;
    border: 1px solid rgba(245, 158, 11, 0.3);
}

.diff-hard {
    background: rgba(244, 63, 94, 0.15);
    color: #f43f5e;
    border: 1px solid rgba(244, 63, 94, 0.3);
}

.practice-body {
    padding: 22px;
}

.practice-body h6 {
    font-weight: 700;
    margin-bottom: 12px;
}

.practice-body p {
    font-size: 0.88rem;
    color: var(--text-muted);
    margin: 0;
}

.practice-hint {
    margin-top: 14px;
    padding: 12px 16px;
    background: rgba(129, 140, 248, 0.06);
    border-radius: 8px;
    border-left: 3px solid var(--accent2);
    font-size: 0.82rem;
    color: var(--text-muted);
}

/* REVISION */
.revision-item {
    display: flex;
    align-items: flex-start;
    gap: 14px;
    padding: 16px 20px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    margin-bottom: 12px;
    transition: all 0.3s;
}

.revision-item:hover {
    border-color: rgba(129, 140, 248, 0.35);
    transform: translateX(6px);
    background: var(--bg-hover);
}

.revision-check {
    width: 28px;
    height: 28px;
    min-width: 28px;
    background: rgba(34, 197, 94, 0.15);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #22c55e;
    font-size: 0.85rem;
}

/* PROGRESS */
.progress-section {
    background: linear-gradient(135deg, rgba(129, 140, 248, 0.08), rgba(56, 189, 248, 0.08));
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 36px;
    position: relative;
    overflow: hidden;
}

.progress-section::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -100px;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(129, 140, 248, 0.15), transparent 70%);
    pointer-events: none;
}

.progress-steps {
    display: flex;
    gap: 0;
    position: relative;
    margin: 30px 0;
    overflow: hidden;
}

.progress-steps::before {
    content: '';
    position: absolute;
    top: 20px;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--bg-hover);
    z-index: 0;
}

.progress-step {
    flex: 1;
    text-align: center;
    position: relative;
    z-index: 1;
}

.ps-circle {
    width: 42px;
    height: 42px;
    border-radius: 50%;
    margin: 0 auto 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.85rem;
    font-weight: 700;
    border: 3px solid;
    position: relative;
    background: var(--bg-main);
}

.ps-done {
    border-color: #22c55e;
    color: #22c55e;
    background: rgba(34, 197, 94, 0.1);
}

.ps-active {
    border-color: #818cf8;
    color: #818cf8;
    background: rgba(129, 140, 248, 0.1);
    box-shadow: 0 0 20px rgba(129, 140, 248, 0.4);
    animation: pulse2 2s infinite;
}

.ps-pending {
    border-color: var(--text-dim);
    color: var(--text-dim);
}

@keyframes pulse2 {

    0%,
    100% {
        box-shadow: 0 0 15px rgba(129, 140, 248, 0.3)
    }

    50% {
        box-shadow: 0 0 30px rgba(129, 140, 248, 0.6)
    }
}

.ps-label {
    font-size: 0.72rem;
    color: var(--text-muted);
    font-weight: 600;
}

.big-progress {
    height: 12px;
    background: var(--bg-hover);
    border-radius: 6px;
    overflow: hidden;
}

.big-progress-bar {
    height: 100%;
    background: linear-gradient(90deg, #818cf8, #38bdf8);
    border-radius: 6px;
    animation: growBar 1.5s ease-out forwards;
    transform-origin: left;
}

@keyframes growBar {
    from {
        width: 0
    }

    to {
        width: 16.66%
    }
}

/* CHECKLIST */
.check-item {
    display: flex;
    align-items: center;
    gap: 12px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 14px 18px;
    transition: all 0.3s;
    cursor: pointer;
}

.check-item:hover {
    border-color: rgba(34, 197, 94, 0.4);
    background: rgba(34, 197, 94, 0.04);
}

.check-box {
    width: 22px;
    height: 22px;
    border-radius: 6px;
    border: 2px solid var(--text-dim);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s;
    flex-shrink: 0;
    font-size: 0.75rem;
    color: transparent;
}

.check-item.checked .check-box {
    background: #22c55e;
    border-color: #22c55e;
    color: #fff;
}

.check-item.checked .check-label {
    text-decoration: line-through;
    color: var(--text-dim);
}

.check-label {
    font-size: 0.88rem;
    font-weight: 500;
}

/* USECASE CARD */
.usecase-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 26px;
    text-align: center;
    transition: all 0.35s;
    height: 100%;
}

.usecase-card:hover {
    border-color: rgba(129, 140, 248, 0.4);
    transform: translateY(-8px);
    box-shadow: 0 25px 50px rgba(0, 0, 0, 0.3);
}

.uc-icon {
    width: 64px;
    height: 64px;
    border-radius: 18px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.6rem;
    margin: 0 auto 18px;
}

/* MEMORY BOX */
.memory-visual {
    background: var(--bg-card2);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
}

.mem-row {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-bottom: 14px;
}

.mem-label {
    font-family: 'Fira Code', monospace;
    font-size: 0.85rem;
    color: var(--accent2);
    min-width: 80px;
}

.mem-arrow {
    color: var(--text-dim);
    font-size: 0.9rem;
}

.mem-box {
    border-radius: 8px;
    padding: 8px 18px;
    font-family: 'Fira Code', monospace;
    font-size: 0.88rem;
    font-weight: 600;
    border: 1px solid;
}

/* CASTING FLOW */
.cast-flow {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
    justify-content: center;
}

.cast-box {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 12px 20px;
    text-align: center;
}

.cast-fn {
    font-family: 'Fira Code', monospace;
    font-size: 0.8rem;
    color: var(--accent2);
    margin-bottom: 4px;
    font-weight: 700;
}

.cast-result {
    font-family: 'Fira Code', monospace;
    font-size: 0.82rem;
}

.cast-arrow {
    color: var(--accent);
    font-size: 1rem;
}

/* ROADMAP */
.roadmap {
    position: relative;
    padding-left: 32px;
}

.roadmap::before {
    content: '';
    position: absolute;
    left: 12px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: linear-gradient(180deg, #818cf8, #38bdf8, #22c55e);
}

.roadmap-item {
    position: relative;
    margin-bottom: 28px;
}

.roadmap-dot {
    position: absolute;
    left: -26px;
    top: 4px;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: linear-gradient(135deg, #818cf8, #38bdf8);
    box-shadow: 0 0 12px rgba(129, 140, 248, 0.4);
}

.roadmap-content {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 18px 22px;
    transition: all 0.3s;
}

.roadmap-content:hover {
    border-color: rgba(129, 140, 248, 0.35);
    transform: translateX(6px);
}

/* FOOTER */
.site-footer {
    background: var(--bg-deep);
    border-top: 1px solid var(--border);
    padding: 50px 0 30px;
}

/* BACK TO TOP */
#backToTop {
    position: fixed;
    bottom: 28px;
    right: 28px;
    z-index: 999;
    width: 48px;
    height: 48px;
    border-radius: 12px;
    background: linear-gradient(135deg, #818cf8, #38bdf8);
    border: none;
    color: #fff;
    font-size: 1.1rem;
    cursor: pointer;
    opacity: 0;
    transform: translateY(20px);
    transition: all 0.3s;
    box-shadow: 0 8px 24px rgba(129, 140, 248, 0.35);
}

#backToTop.visible {
    opacity: 1;
    transform: translateY(0);
}

#backToTop:hover {
    transform: translateY(-4px);
}

.section-gap {
    padding: 80px 0;
}

.section-gap-sm {
    padding: 50px 0;
}

.mb-section {
    margin-bottom: 56px;
}

.illustration-wrap {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px 0;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px)
    }

    to {
        opacity: 1;
        transform: translateY(0)
    }
}

.animate-hero {
    animation: fadeInUp 0.8s ease-out forwards;
}

.animate-hero-delay-1 {
    animation: fadeInUp 0.8s 0.2s ease-out both;
}

.animate-hero-delay-2 {
    animation: fadeInUp 0.8s 0.4s ease-out both;
}

.animate-hero-delay-3 {
    animation: fadeInUp 0.8s 0.6s ease-out both;
}

@media(max-width:768px) {
    .hero-title {
        font-size: 2.2rem;
    }

    .flow-container {
        flex-direction: column;
    }

    .flow-arrow {
        transform: rotate(90deg);
    }

    .floating-badge-1,
    .floating-badge-2 {
        display: none;
    }

    .progress-steps {
        gap: 0;
    }

    .ps-label {
        font-size: 0.62rem;
    }

    .cast-flow {
        flex-direction: column;
    }
}

/* ===========================
   FULL FOOTER (updated)
=========================== */
.footer-grid {
  display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 40px;
  margin-bottom: 40px;
}
.footer-brand-name {
  font-family: 'Syne', sans-serif; font-size: 1.4rem; font-weight: 800;
  background: linear-gradient(135deg, #38bdf8, #818cf8);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text; margin-bottom: 12px;
}
.footer-tagline { font-size: 0.88rem; color: var(--text-muted); margin-bottom: 20px; }
.footer-social { display: flex; gap: 10px; }
.footer-social-link {
  width: 36px; height: 36px; border-radius: 8px;
  background: var(--bg-card); border: 1px solid var(--border);
  display: flex; align-items: center; justify-content: center;
  color: var(--text-muted); font-size: 0.9rem; text-decoration: none;
  transition: all 0.25s;
}
.footer-social-link:hover { border-color: var(--accent); color: var(--accent); }
.footer-col-title { font-weight: 700; font-size: 0.85rem; margin-bottom: 16px; color: var(--text-main); }
.footer-link {
  display: block; color: var(--text-muted); font-size: 0.85rem;
  text-decoration: none; margin-bottom: 10px; transition: color 0.2s;
}
.footer-link:hover { color: var(--accent); }
.footer-bottom {
  border-top: 1px solid var(--border); padding-top: 24px;
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: 12px;
}
.footer-copy { font-size: 0.8rem; color: var(--text-dim); }
.footer-love { font-size: 0.85rem; color: var(--text-muted); }
.footer-love a { color: var(--accent); text-decoration: none; }
.footer-love a:hover { color: #818cf8; }
@media(max-width:992px){ .footer-grid { grid-template-columns: 1fr 1fr; } }
@media(max-width:576px){ .footer-grid { grid-template-columns: 1fr; gap: 28px; } }