:root {
    /* Color Palette: Obsidian & Ember */
    --bg-dark: #0f0e0d;
    --bg-card: #181615;
    --bg-card-hover: #221f1d;
    --text-primary: #f0ebe1;
    --text-secondary: #a39e93;
    --text-muted: #7a766d;
    --accent-orange: #E85D04;
    --accent-orange-bright: #F48C06;
    --accent-orange-dim: rgba(232, 93, 4, 0.15);
    --accent-glow: rgba(232, 93, 4, 0.4);
    --accent-blue: #0088ff;
    --border-color: #2e2a27;

    /* Fonts */
    --font-main: 'LXGW WenKai TC', 'Noto Serif TC', serif;
    --font-serif: 'Noto Serif TC', "Times New Roman", serif;

    --transition-fast: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-smooth: all 0.5s cubic-bezier(0.2, 0.8, 0.2, 1);
    --transition-slow: all 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}

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

html {
    scroll-behavior: smooth;
    background-color: var(--bg-dark);
}

body {
    background-color: var(--bg-dark);
    color: var(--text-primary);
    font-family: var(--font-main);
    line-height: 1.7;
    overflow-x: hidden;
    position: relative;
    background-image:
        radial-gradient(circle at 15% 50%, rgba(255, 85, 0, 0.03) 0%, transparent 50%),
        radial-gradient(circle at 85% 30%, rgba(0, 136, 255, 0.02) 0%, transparent 50%);
}

::selection {
    background: var(--accent-orange);
    color: #fff;
}

/* Background Effects */
.bg-glow {
    position: fixed;
    top: -30vh;
    right: -20vw;
    width: 60vw;
    height: 60vw;
    background: radial-gradient(circle, var(--accent-orange-dim) 0%, transparent 60%);
    filter: blur(120px);
    z-index: -2;
    pointer-events: none;
    animation: flow 20s ease-in-out infinite alternate;
}

.bg-grid {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background-size: 50px 50px;
    background-image: linear-gradient(to right, rgba(255, 255, 255, 0.02) 1px, transparent 1px), linear-gradient(to bottom, rgba(255, 255, 255, 0.02) 1px, transparent 1px);
    z-index: -3;
    pointer-events: none;
}

@keyframes flow {
    0% {
        transform: translate(0, 0);
    }

    100% {
        transform: translate(-10%, 10%);
    }
}

/* Navigation */
nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 5%;
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    background: rgba(7, 7, 7, 0.8);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.logo {
    font-size: 1.3rem;
    font-weight: 900;
    letter-spacing: 2px;
    display: flex;
    align-items: center;
    gap: 0.8rem;
    text-shadow: 0 0 10px rgba(255, 255, 255, 0.2);
}

.logo span {
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--accent-orange);
    text-transform: uppercase;
    letter-spacing: 2px;
    opacity: 0.8;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 2.5rem;
}

.nav-links a:not(.nav-contact) {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    position: relative;
    padding: 0.5rem 0;
    transition: var(--transition-fast);
}

.nav-links a:not(.nav-contact)::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent-orange);
    transition: var(--transition-smooth);
}

.nav-links a:not(.nav-contact):hover {
    color: var(--text-primary);
}

.nav-links a:not(.nav-contact):hover::after {
    width: 100%;
}

.hamburger {
    display: none;
    flex-direction: column;
    gap: 0;
    cursor: pointer;
    z-index: 1001;
    /* Above nav-links when open */
    padding: 12px;
    margin-right: -12px;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--border-color);
    border-radius: 50%;
    width: 46px;
    height: 46px;
    justify-content: center;
    align-items: center;
    transition: var(--transition-smooth);
}

.hamburger:hover {
    background: var(--accent-orange-dim);
    border-color: var(--accent-orange);
    box-shadow: 0 0 15px var(--accent-glow);
}

.hamburger span {
    display: block;
    width: 20px;
    height: 2px;
    background: var(--text-primary);
    transition: var(--transition-smooth);
    border-radius: 1px;
    position: absolute;
}

.hamburger span:nth-child(1) {
    transform: translateY(-4px);
}

.hamburger span:nth-child(2) {
    width: 14px;
    transform: translateY(4px);
    margin-left: 6px;
}

.hamburger.open span:nth-child(1) {
    transform: translateY(0) rotate(45deg);
}

.hamburger.open span:nth-child(2) {
    width: 20px;
    margin-left: 0;
    transform: translateY(0) rotate(-45deg);
}

.nav-contact {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.9rem;
    padding: 0.6rem 1.5rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-color);
    border-radius: 50px;
    transition: var(--transition-smooth);
}

.nav-contact:hover {
    border-color: var(--accent-orange);
    background: var(--accent-orange-dim);
    color: #fff;
    box-shadow: 0 0 20px rgba(255, 85, 0, 0.2);
}

/* Typography styles & Widow prevention */
h1,
h2,
h3,
h4,
h5,
h6,
blockquote,
.subtitle,
.intro {
    text-wrap: balance;
}

p,
li,
span,
.detail-text {
    text-wrap: pretty;
    text-align: justify;
    line-height: 1.85;
    letter-spacing: 0.05em;
    word-break: keep-all;
}

h1 {
    font-family: var(--font-serif);
    font-size: clamp(2.5rem, 5vw, 4.5rem);
    line-height: 1.25;
    font-weight: 900;
    margin-bottom: 1.5rem;
    letter-spacing: -0.5px;
}

h2 {
    font-family: var(--font-serif);
    font-size: clamp(2rem, 3.5vw, 3rem);
    font-weight: 900;
    margin-bottom: 1rem;
    letter-spacing: 0px;
}

h3 {
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: 0.8rem;
    color: var(--text-primary);
    letter-spacing: 0.5px;
}

.highlight {
    color: var(--accent-orange);
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 6rem 5% 0;
    position: relative;
    gap: 4rem;
}

.badge {
    display: inline-block;
    padding: 0.4rem 1rem;
    border: 1px solid var(--accent-orange);
    color: var(--accent-orange);
    border-radius: 50px;
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    background: var(--accent-orange-dim);
    box-shadow: 0 0 15px var(--accent-glow);
}

.hero-content {
    flex: 1.2;
    max-width: 700px;
    z-index: 10;
}

.subtitle {
    font-size: 1.3rem;
    color: var(--text-primary);
    margin-bottom: 2rem;
    font-weight: 500;
    border-left: 3px solid var(--accent-orange);
    padding-left: 1rem;
}

.intro {
    font-size: 1.05rem;
    color: var(--text-secondary);
    margin-bottom: 3rem;
    line-height: 1.9;
}

.hero-image {
    flex: 0.8;
    display: flex;
    justify-content: center;
    align-items: center;
}

/* 3D abstract visualization for Hero */
.cube-container {
    width: 300px;
    height: 300px;
    position: relative;
    transform-style: preserve-3d;
    display: flex;
    justify-content: center;
    align-items: center;
}

.rings-wrapper {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    transform-style: preserve-3d;
    animation: global-orbit 25s linear infinite;
    display: flex;
    justify-content: center;
    align-items: center;
}

.glowing-sphere {
    position: absolute;
    width: 130px;
    height: 130px;
    background: radial-gradient(circle at 30% 30%, #ff8c42, var(--accent-orange) 55%, #662200);
    border-radius: 50%;
    box-shadow: 0 0 60px var(--accent-orange), inset -20px -20px 40px rgba(0, 0, 0, 0.8), inset 10px 10px 30px rgba(255, 230, 204, 0.5);
    z-index: 10;
    overflow: hidden;
}

.glowing-sphere::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 200%;
    height: 100%;
    background-image:
        radial-gradient(circle at 10% 40%, rgba(80, 20, 0, 0.6) 8%, transparent 20%),
        radial-gradient(circle at 30% 70%, rgba(50, 10, 0, 0.7) 12%, transparent 25%),
        radial-gradient(circle at 60% 30%, rgba(90, 25, 0, 0.5) 10%, transparent 20%),
        radial-gradient(circle at 85% 65%, rgba(60, 15, 0, 0.8) 15%, transparent 30%);
    background-size: 50% 100%;
    animation: mars-spin 12s linear infinite;
    mix-blend-mode: color-burn;
}

.ring {
    position: absolute;
    border-radius: 50%;
    border: 1px solid rgba(255, 255, 255, 0.1);
    transform-style: preserve-3d;
}

.ring-1 {
    width: 160px;
    height: 160px;
    border-color: rgba(255, 85, 0, 0.4);
    animation: orbit-1 3s linear infinite;
}

.ring-2 {
    width: 200px;
    height: 200px;
    border-color: rgba(255, 255, 255, 0.1);
    animation: orbit-2 5s linear infinite;
}

.ring-3 {
    width: 240px;
    height: 240px;
    border-color: rgba(255, 85, 0, 0.2);
    border-left-color: var(--accent-orange);
    animation: orbit-3 2.5s linear infinite;
}

.ring-4 {
    width: 300px;
    height: 300px;
    border-color: rgba(255, 85, 0, 0.1);
    border-right-color: var(--accent-orange-bright);
    border-top-color: rgba(255, 255, 255, 0.2);
    animation: orbit-4 4s linear infinite;
}

.ring-5 {
    width: 360px;
    height: 360px;
    border-color: rgba(255, 85, 0, 0.05);
    border-bottom-color: var(--accent-orange);
    animation: orbit-5 6s linear infinite;
}

.ring-6 {
    width: 440px;
    height: 440px;
    border-color: rgba(255, 255, 255, 0.03);
    border-right-color: var(--accent-orange-dim);
    animation: orbit-6 8s linear infinite;
}

@keyframes global-orbit {
    0% {
        transform: rotateX(20deg) rotateY(0deg);
    }

    100% {
        transform: rotateX(20deg) rotateY(360deg);
    }
}

@keyframes mars-spin {
    0% {
        transform: translateX(0);
    }

    100% {
        transform: translateX(-50%);
    }
}

@keyframes orbit-1 {
    0% {
        transform: rotateX(70deg) rotateY(20deg) rotateZ(0deg);
    }

    100% {
        transform: rotateX(70deg) rotateY(20deg) rotateZ(360deg);
    }
}

@keyframes orbit-2 {
    0% {
        transform: rotateX(40deg) rotateY(-30deg) rotateZ(0deg);
    }

    100% {
        transform: rotateX(40deg) rotateY(-30deg) rotateZ(-360deg);
    }
}

@keyframes orbit-3 {
    0% {
        transform: rotateX(80deg) rotateY(50deg) rotateZ(0deg);
    }

    100% {
        transform: rotateX(80deg) rotateY(50deg) rotateZ(360deg);
    }
}

@keyframes orbit-4 {
    0% {
        transform: rotateX(30deg) rotateY(70deg) rotateZ(0deg);
    }

    100% {
        transform: rotateX(30deg) rotateY(70deg) rotateZ(-360deg);
    }
}

@keyframes orbit-5 {
    0% {
        transform: rotateX(60deg) rotateY(-60deg) rotateZ(0deg);
    }

    100% {
        transform: rotateX(60deg) rotateY(-60deg) rotateZ(360deg);
    }
}

@keyframes orbit-6 {
    0% {
        transform: rotateX(75deg) rotateY(10deg) rotateZ(0deg);
    }

    100% {
        transform: rotateX(75deg) rotateY(10deg) rotateZ(-360deg);
    }
}

/* Buttons */
.cta-button {
    display: inline-block;
    padding: 1rem 2rem;
    text-decoration: none;
    font-weight: 700;
    font-size: 1rem;
    border-radius: 6px;
    transition: var(--transition-smooth);
    text-align: center;
    cursor: pointer;
    border: none;
    margin-right: 1rem;
    margin-bottom: 1rem;
}

.cta-button.primary {
    background: var(--accent-orange);
    color: #000;
    box-shadow: 0 4px 20px var(--accent-orange-dim);
}

.cta-button.primary:hover {
    background: #ff6b1a;
    box-shadow: 0 8px 30px var(--accent-glow);
    transform: translateY(-2px);
}

.cta-button.secondary {
    background: transparent;
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.cta-button.secondary:hover {
    border-color: var(--text-primary);
    background: rgba(255, 255, 255, 0.05);
}

.cta-button.large {
    padding: 1.2rem 3rem;
    font-size: 1.1rem;
}

/* Quote Section */
.quote-section {
    padding: 5rem 5%;
    text-align: center;
    background: linear-gradient(to right, transparent, rgba(255, 255, 255, 0.02), transparent);
    border-top: 1px solid rgba(255, 255, 255, 0.03);
    border-bottom: 1px solid rgba(255, 255, 255, 0.03);
}

blockquote {
    font-size: clamp(1.5rem, 2.5vw, 2rem);
    font-weight: 300;
    max-width: 900px;
    margin: 0 auto;
    color: var(--text-primary);
    line-height: 1.6;
    font-style: italic;
}

blockquote::before {
    content: '"';
    color: var(--accent-orange);
    opacity: 0.5;
    font-size: 3rem;
    line-height: 0;
    vertical-align: bottom;
    margin-right: 10px;
}

/* Section Common */
section {
    padding: 8rem 5%;
}

.section-title {
    max-width: 800px;
    margin: 0 auto 5rem;
    text-align: center;
}

.section-title p {
    color: var(--text-secondary);
    font-size: 1.2rem;
    margin-top: 1rem;
}

/* Concepts Stepper */
.stepper {
    max-width: 900px;
    margin: 0 auto;
    position: relative;
}

.stepper::before {
    content: '';
    position: absolute;
    top: 0;
    left: 24px;
    height: 100%;
    width: 2px;
    background: linear-gradient(to bottom, var(--accent-orange), rgba(255, 85, 0, 0.2), transparent);
}

.step {
    position: relative;
    padding-left: 80px;
    margin-bottom: 3rem;
}

.step-number {
    position: absolute;
    left: 0;
    top: 0;
    width: 50px;
    height: 50px;
    background: var(--bg-dark);
    border: 2px solid var(--accent-orange);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 900;
    color: var(--text-primary);
    font-size: 1.2rem;
    z-index: 2;
    box-shadow: 0 0 15px var(--accent-orange-dim);
    transition: var(--transition-smooth);
}

.step:hover .step-number {
    background: var(--accent-orange);
    color: #000;
    transform: scale(1.1);
    box-shadow: 0 0 25px var(--accent-glow);
}

.step-content {
    background: var(--bg-card);
    padding: 2.5rem;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    transition: var(--transition-smooth);
    position: relative;
    overflow: hidden;
}

.step-content::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 0;
    background: var(--accent-orange);
    transition: var(--transition-smooth);
}

.step:hover .step-content {
    background: var(--bg-card-hover);
    border-color: rgba(255, 85, 0, 0.3);
    transform: translateX(10px);
}

.step:hover .step-content::after {
    height: 100%;
}

.step-content p {
    color: var(--text-primary);
    font-size: 1.1rem;
    margin-bottom: 1rem;
}

.step-content .detail-text {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin-bottom: 0;
}

/* Calculator Section */
.calculator-section {
    background-color: #0a0a0a;
    position: relative;
}

.calculator-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 1px;
    background: linear-gradient(to right, transparent, var(--border-color), transparent);
}

.calculator-container {
    max-width: 1000px;
    margin: 0 auto;
    background: rgba(18, 18, 18, 0.6);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    padding: 4rem;
    backdrop-filter: blur(10px);
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.5);
}

.calc-header {
    text-align: center;
    margin-bottom: 4rem;
}

.calc-header h2 {
    font-size: 2.2rem;
}

.calc-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    margin-bottom: 3rem;
}

.calc-card {
    background: rgba(255, 255, 255, 0.02);
    border: 1px solid rgba(255, 255, 255, 0.05);
    border-radius: 12px;
    padding: 2rem;
    transition: var(--transition-fast);
}

.calc-card:hover {
    border-color: rgba(255, 255, 255, 0.1);
    background: rgba(255, 255, 255, 0.04);
}

.calc-card h3 {
    text-align: center;
    color: var(--accent-orange);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    padding-bottom: 1rem;
    margin-bottom: 1.5rem;
    display: flex;
    flex-direction: column;
}

.calc-card h3 span {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-weight: 400;
    margin-top: 5px;
}

.input-group {
    margin-bottom: 1.5rem;
}

.input-group label {
    display: block;
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.row {
    display: flex;
    gap: 1rem;
}

.field {
    flex: 1;
}

.field span {
    display: block;
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-bottom: 4px;
}

input[type="number"] {
    width: 100%;
    background: #000;
    border: 1px solid var(--border-color);
    color: #fff;
    padding: 0.8rem;
    border-radius: 6px;
    font-family: inherit;
    font-size: 1rem;
    transition: var(--transition-fast);
}

input[type="number"]:focus {
    outline: none;
    border-color: var(--accent-orange);
    box-shadow: 0 0 15px var(--accent-glow);
}

input[type="number"]:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.expected-value-display {
    margin-top: 2rem;
    background: rgba(0, 0, 0, 0.5);
    padding: 1rem;
    border-radius: 8px;
    text-align: center;
    font-size: 1.1rem;
    color: var(--text-secondary);
}

.expected-value-display span {
    font-size: 1.5rem;
    font-weight: 900;
    color: #fff;
    margin-left: 10px;
}

.calc-actions {
    text-align: center;
    margin-top: 2rem;
}

.calc-winner {
    margin-top: 3rem;
    text-align: center;
    padding: 3rem 2rem;
    background: rgba(255, 85, 0, 0.05);
    border: 1px solid rgba(255, 85, 0, 0.2);
    border-radius: 12px;
    transition: var(--transition-slow);
}

.calc-winner.hidden {
    opacity: 0;
    transform: translateY(20px);
    pointer-events: none;
    display: none;
}

.calc-winner.show {
    display: block;
    animation: fadeInSlideUp 0.6s forwards;
}

@keyframes fadeInSlideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

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

#winner-text {
    font-size: 1.8rem;
    color: #fff;
    margin-bottom: 1rem;
}

#winner-desc {
    color: var(--text-secondary);
    margin-bottom: 2rem;
    max-width: 600px;
    margin-inline: auto;
}

.meter-bar {
    width: 100%;
    height: 12px;
    background: #222;
    border-radius: 10px;
    position: relative;
    overflow: hidden;
    margin-bottom: 0.5rem;
}

.meter-fill {
    height: 100%;
    width: 50%;
    /* dynamically set */
    background: linear-gradient(90deg, #ff5500, #ffaa00);
    border-radius: 10px;
    transition: width 1s cubic-bezier(0.2, 1, 0.3, 1);
}

.meter-labels {
    display: flex;
    justify-content: space-between;
    font-size: 0.8rem;
    color: var(--text-muted);
}

/* Accordion Deep Dive */
.deep-dive {
    background: var(--bg-dark);
}

.accordion-container {
    max-width: 800px;
    margin: 0 auto;
}

.accordion-item {
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 1rem;
}

.accordion-header {
    width: 100%;
    text-align: left;
    padding: 1.5rem 0;
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-size: 1.2rem;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: var(--transition-fast);
}

.accordion-header:hover {
    color: var(--accent-orange);
}

.accordion-header span {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-right: 15px;
    font-family: monospace;
}

.icon-cross {
    width: 20px;
    height: 20px;
    position: relative;
}

.icon-cross::before,
.icon-cross::after {
    content: '';
    position: absolute;
    background: var(--text-secondary);
    transition: var(--transition-smooth);
}

.icon-cross::before {
    top: 9px;
    left: 0;
    width: 20px;
    height: 2px;
}

.icon-cross::after {
    top: 0;
    left: 9px;
    width: 2px;
    height: 20px;
}

.accordion-item.open .icon-cross::after {
    transform: rotate(90deg);
    opacity: 0;
}

.accordion-item.open .icon-cross::before {
    background: var(--accent-orange);
}

.accordion-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease-out;
    padding-left: 2.5rem;
    padding-right: 1rem;
}

.accordion-content p {
    padding-bottom: 1.5rem;
    color: var(--text-secondary);
}

.accordion-content p:first-child {
    padding-top: 1rem;
}

.accordion-content p strong {
    color: var(--text-primary);
}

/* Marquee */
.marquee-wrapper {
    background: var(--accent-orange);
    padding: 1.2rem 0;
    overflow: hidden;
    position: relative;
    transform: rotate(-1.5deg) scale(1.05);
    z-index: 10;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
}

.marquee {
    display: flex;
    white-space: nowrap;
    width: max-content;
    animation: animate-marquee 25s linear infinite;
}

.marquee span {
    font-size: 1.3rem;
    font-weight: 900;
    color: #0d0c0b;
    text-transform: uppercase;
    padding: 0 1rem;
    letter-spacing: 2.5px;
    font-family: var(--font-serif);
}

@keyframes animate-marquee {
    0% {
        transform: translateX(0);
    }

    100% {
        transform: translateX(-50%);
    }
}

/* CTA Section */
.cta-section {
    background: var(--bg-card);
    padding: 10rem 5%;
    position: relative;
}

.cta-wrapper {
    max-width: 1000px;
    margin: 0 auto;
    background: rgba(10, 10, 10, 0.8);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    padding: 6rem 3rem;
    position: relative;
    overflow: hidden;
    box-shadow: 0 30px 60px rgba(0, 0, 0, 0.8);
}

.bg-shape-1 {
    position: absolute;
    top: -50px;
    left: -50px;
    width: 200px;
    height: 200px;
    background: var(--accent-orange);
    opacity: 0.1;
    filter: blur(50px);
    border-radius: 50%;
}

.bg-shape-2 {
    position: absolute;
    bottom: -100px;
    right: -50px;
    width: 300px;
    height: 300px;
    background: #ffaa00;
    opacity: 0.05;
    filter: blur(80px);
    border-radius: 50%;
}

.cta-content {
    position: relative;
    z-index: 1;
    text-align: center;
}

.cta-content p {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 3rem;
}

.contact-methods {
    display: flex;
    gap: 1.5rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* Sticky Contact */
.sticky-contact {
    position: fixed;
    right: 30px;
    bottom: 30px;
    background: var(--bg-card);
    border: 1px solid rgba(255, 85, 0, 0.3);
    padding: 1rem 1.2rem;
    border-radius: 50px;
    display: flex;
    align-items: center;
    gap: 0.8rem;
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 600;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.8);
    z-index: 99;
    transition: var(--transition-smooth);
    overflow: hidden;
}

.sticky-contact::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.1), transparent);
    transition: left 0.5s ease;
}

.sticky-contact:hover::before {
    left: 100%;
}

.sticky-contact:hover {
    border-color: var(--accent-orange);
    background: var(--accent-orange-dim);
    transform: translateY(-5px);
}

.sticky-contact .icon {
    font-size: 1.3rem;
}

/* Footer */
footer {
    text-align: center;
    padding: 3rem;
    border-top: 1px solid var(--border-color);
    color: var(--text-muted);
    font-size: 0.9rem;
    background: var(--bg-dark);
}

/* Utilities for Animations */
.reveal-item {
    opacity: 0;
    transform: translateY(40px);
    transition: all 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}

.reveal-item.active {
    opacity: 1;
    transform: translateY(0);
}

/* Responsive */
@media (max-width: 900px) {
    .hamburger {
        display: flex;
    }

    .nav-links {
        position: fixed;
        top: 0;
        left: 0;
        width: 100vw;
        height: 100vh;
        background: radial-gradient(circle at right top, rgba(20, 15, 13, 0.98), rgba(7, 7, 7, 0.99));
        backdrop-filter: blur(30px);
        -webkit-backdrop-filter: blur(30px);
        flex-direction: column;
        justify-content: center;
        align-items: flex-start;
        padding-left: 15vw;
        gap: 0;
        opacity: 0;
        visibility: hidden;
        transform: scale(1.02);
        transition: all 0.5s cubic-bezier(0.16, 1, 0.3, 1);
        z-index: 1000;
        border-left: none;
        box-shadow: none;
    }

    .nav-links::before {
        content: 'COMBUSTIBLE';
        position: absolute;
        left: 3vw;
        bottom: 5vh;
        font-family: var(--font-serif);
        font-size: 5rem;
        font-weight: 900;
        color: rgba(255, 255, 255, 0.02);
        transform: rotate(-90deg);
        transform-origin: left bottom;
        pointer-events: none;
        letter-spacing: 10px;
        white-space: nowrap;
    }

    .nav-links.open {
        opacity: 1;
        visibility: visible;
        transform: scale(1);
    }

    .nav-links a:not(.nav-contact) {
        font-family: var(--font-serif);
        font-size: 2.8rem;
        font-weight: 300;
        margin-bottom: 2rem;
        color: var(--text-primary);
        opacity: 0;
        transform: translateX(-40px);
        transition: all 0.5s cubic-bezier(0.16, 1, 0.3, 1);
        position: relative;
        text-transform: none;
        letter-spacing: 2px;
    }

    .nav-links a:not(.nav-contact)::before {
        content: '';
        position: absolute;
        left: -20px;
        top: 50%;
        width: 0;
        height: 2px;
        background: var(--accent-orange);
        transition: width 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    }

    .nav-links a:not(.nav-contact):hover {
        color: var(--text-primary);
    }

    .nav-links a:not(.nav-contact):hover::before {
        width: 15px;
    }

    .nav-links a:not(.nav-contact)::after {
        display: none;
    }

    .nav-links.open a:not(.nav-contact) {
        opacity: 1;
        transform: translateX(0);
    }

    .nav-links.open a:not(.nav-contact):nth-child(1) {
        transition-delay: 0.1s;
    }

    .nav-links.open a:not(.nav-contact):nth-child(2) {
        transition-delay: 0.2s;
    }

    .nav-links.open a:not(.nav-contact):nth-child(3) {
        transition-delay: 0.3s;
    }

    .nav-contact {
        margin-top: 2rem;
        font-size: 1.1rem;
        padding: 1rem 2.5rem;
        opacity: 0;
        transform: translateX(-40px);
        transition: all 0.5s cubic-bezier(0.16, 1, 0.3, 1);
        border: 1px solid var(--accent-orange);
        background: rgba(255, 85, 0, 0.1);
        color: var(--accent-orange);
    }

    .nav-links.open .nav-contact {
        opacity: 1;
        transform: translateX(0);
        transition-delay: 0.4s;
    }

    .hero {
        flex-direction: column;
        text-align: center;
        padding-top: 8rem;
    }

    .subtitle {
        border-left: none;
        padding-left: 0;
    }

    .hero-content {
        align-items: center;
        width: 100%;
    }

    .cta-button {
        width: 100%;
        margin-right: 0;
    }

    .stepper::before {
        left: 0;
    }

    .step {
        padding-left: 0;
        padding-top: 50px;
    }

    .step-number {
        left: 50%;
        transform: translateX(-50%);
        top: -25px;
    }

    .step:hover .step-number {
        transform: translateX(-50%) scale(1.1);
    }

    .calc-grid {
        grid-template-columns: 1fr;
    }

    .calculator-container {
        padding: 2rem 1.5rem;
    }
}