/* Credits Equalance - B.Tech CS Calculator */
/* Design System: Indigo Ink + Editorial Typography */

:root {
    /* Indigo Ink Palette */
    --color-bg-primary: #0A0A0F;
    --color-bg-secondary: #12121A;
    --color-bg-tertiary: #1A1A25;
    --color-accent-primary: #7B68EE;
    --color-accent-secondary: #9D8DF2;
    --color-accent-glow: rgba(123, 104, 238, 0.3);
    --color-text-primary: #F5F5F7;
    --color-text-secondary: #A0A0B0;
    --color-text-muted: #6B6B7B;
    --color-border: rgba(123, 104, 238, 0.2);
    --color-success: #4ADE80;
    --color-warning: #FBBF24;
    
    /* Typography */
    --font-display: 'Playfair Display', serif;
    --font-body: 'Plus Jakarta Sans', sans-serif;
    
    /* Spacing */
    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 1.5rem;
    --space-lg: 2rem;
    --space-xl: 3rem;
    --space-2xl: 4rem;
    --space-3xl: 6rem;
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-medium: 0.3s ease;
    --transition-slow: 0.5s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    background-color: var(--color-bg-primary);
    color: var(--color-text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

/* Noise Overlay */
.noise-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 1000;
    opacity: 0.03;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)'/%3E%3C/svg%3E");
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-md) var(--space-xl);
    background: rgba(10, 10, 15, 0.8);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--color-border);
    z-index: 100;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
}

.brand-icon {
    font-size: 1.5rem;
    color: var(--color-accent-primary);
}

.brand-text {
    font-family: var(--font-display);
    font-size: 1.25rem;
    font-weight: 600;
    letter-spacing: -0.02em;
}

.nav-links {
    display: flex;
    gap: var(--space-lg);
}

.nav-link {
    color: var(--color-text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: color var(--transition-fast);
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-accent-primary);
    transition: width var(--transition-medium);
}

.nav-link:hover {
    color: var(--color-text-primary);
}

.nav-link:hover::after {
    width: 100%;
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: grid;
    grid-template-columns: 1fr 1fr;
    align-items: center;
    padding: calc(var(--space-3xl) + 4rem) var(--space-xl) var(--space-3xl);
    gap: var(--space-3xl);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 800px;
    height: 800px;
    background: radial-gradient(circle, var(--color-accent-glow) 0%, transparent 70%);
    pointer-events: none;
}

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

.hero-badge {
    display: inline-block;
    padding: var(--space-xs) var(--space-md);
    background: rgba(123, 104, 238, 0.1);
    border: 1px solid var(--color-border);
    border-radius: 100px;
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-accent-secondary);
    margin-bottom: var(--space-lg);
}

.hero-title {
    font-family: var(--font-display);
    font-size: clamp(3rem, 8vw, 6rem);
    font-weight: 700;
    line-height: 1;
    margin-bottom: var(--space-lg);
}

.title-line {
    display: block;
}

.title-line.accent {
    color: var(--color-accent-primary);
    position: relative;
}

.title-line.accent::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 8px;
    background: linear-gradient(90deg, var(--color-accent-primary), transparent);
    opacity: 0.3;
}

.hero-subtitle {
    font-size: 1.1rem;
    color: var(--color-text-secondary);
    max-width: 480px;
    margin-bottom: var(--space-xl);
    line-height: 1.7;
}

.hero-cta {
    display: flex;
    gap: var(--space-md);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-sm) var(--space-lg);
    font-family: var(--font-body);
    font-size: 0.95rem;
    font-weight: 600;
    text-decoration: none;
    border-radius: 8px;
    transition: all var(--transition-medium);
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--color-accent-primary);
    color: white;
    box-shadow: 0 4px 20px rgba(123, 104, 238, 0.4);
}

.btn-primary:hover {
    background: var(--color-accent-secondary);
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(123, 104, 238, 0.5);
}

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

.btn-secondary:hover {
    background: rgba(123, 104, 238, 0.1);
    border-color: var(--color-accent-primary);
}

/* Hero Visual */
.hero-visual {
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
}

.credit-card {
    background: linear-gradient(145deg, var(--color-bg-secondary), var(--color-bg-tertiary));
    border: 1px solid var(--color-border);
    border-radius: 24px;
    padding: var(--space-xl);
    width: 320px;
    box-shadow: 0 25px 80px rgba(0, 0, 0, 0.5), 0 0 60px var(--color-accent-glow);
    position: relative;
    z-index: 2;
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--space-lg);
}

.card-label {
    font-size: 0.85rem;
    color: var(--color-text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

.card-icon {
    font-size: 1.5rem;
    color: var(--color-accent-primary);
}

.card-value {
    font-family: var(--font-display);
    font-size: 4rem;
    font-weight: 700;
    color: var(--color-accent-primary);
    line-height: 1;
    margin-bottom: var(--space-xs);
}

.card-subtitle {
    font-size: 0.9rem;
    color: var(--color-text-muted);
    margin-bottom: var(--space-lg);
}

.card-progress {
    height: 6px;
    background: rgba(123, 104, 238, 0.1);
    border-radius: 3px;
    overflow: hidden;
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--color-accent-primary), var(--color-accent-secondary));
    border-radius: 3px;
    width: 0%;
    transition: width 1s ease;
}

.floating-elements {
    position: absolute;
    width: 100%;
    height: 100%;
    pointer-events: none;
}

.float-item {
    position: absolute;
    font-family: var(--font-display);
    font-size: 1.5rem;
    color: var(--color-accent-primary);
    opacity: 0.3;
    animation: float 6s ease-in-out infinite;
    animation-delay: var(--delay);
}

.float-item:nth-child(1) {
    top: 10%;
    right: 10%;
}

.float-item:nth-child(2) {
    bottom: 20%;
    left: 5%;
}

.float-item:nth-child(3) {
    top: 50%;
    right: 0%;
}

@keyframes float {
    0%, 100% { transform: translateY(0) rotate(0deg); }
    50% { transform: translateY(-20px) rotate(5deg); }
}

/* Section Styles */
section {
    padding: var(--space-3xl) var(--space-xl);
    max-width: 1400px;
    margin: 0 auto;
}

.section-header {
    text-align: center;
    margin-bottom: var(--space-3xl);
}

.section-number {
    display: inline-block;
    font-family: var(--font-display);
    font-size: 0.9rem;
    color: var(--color-accent-primary);
    margin-bottom: var(--space-sm);
}

.section-title {
    font-family: var(--font-display);
    font-size: clamp(2rem, 5vw, 3rem);
    font-weight: 600;
    margin-bottom: var(--space-sm);
}

.section-desc {
    color: var(--color-text-secondary);
    font-size: 1.1rem;
}

/* Calculator Section */
.calculator-section {
    background: var(--color-bg-secondary);
    border-radius: 32px;
    margin: var(--space-xl) auto;
    padding: var(--space-3xl);
}

.calculator-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-xl);
    margin-bottom: var(--space-3xl);
}

.year-block {
    background: var(--color-bg-primary);
    border: 1px solid var(--color-border);
    border-radius: 20px;
    padding: var(--space-lg);
    transition: all var(--transition-medium);
}

.year-block:hover {
    border-color: var(--color-accent-primary);
    box-shadow: 0 10px 40px rgba(123, 104, 238, 0.1);
}

.year-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--space-lg);
    padding-bottom: var(--space-md);
    border-bottom: 1px solid var(--color-border);
}

.year-title {
    font-family: var(--font-display);
    font-size: 1.3rem;
    font-weight: 600;
}

.year-credits {
    font-size: 0.85rem;
    color: var(--color-accent-secondary);
    background: rgba(123, 104, 238, 0.1);
    padding: var(--space-xs) var(--space-sm);
    border-radius: 100px;
}

.semesters {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-md);
}

.semester {
    background: var(--color-bg-secondary);
    border-radius: 12px;
    padding: var(--space-md);
}

.sem-title {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--color-text-secondary);
    margin-bottom: var(--space-sm);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.subjects-list {
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
}

.subject-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-xs) 0;
    border-bottom: 1px solid rgba(123, 104, 238, 0.1);
}

.subject-item:last-child {
    border-bottom: none;
}

.sub-name {
    font-size: 0.8rem;
    color: var(--color-text-secondary);
    flex: 1;
}

.credit-input {
    width: 50px;
    padding: 4px 8px;
    background: var(--color-bg-tertiary);
    border: 1px solid var(--color-border);
    border-radius: 6px;
    color: var(--color-text-primary);
    font-family: var(--font-body);
    font-size: 0.85rem;
    text-align: center;
    transition: all var(--transition-fast);
}

.credit-input:focus {
    outline: none;
    border-color: var(--color-accent-primary);
    box-shadow: 0 0 0 3px var(--color-accent-glow);
}

.credit-input::placeholder {
    color: var(--color-text-muted);
}

.sem-total {
    margin-top: var(--space-sm);
    padding-top: var(--space-sm);
    border-top: 1px solid var(--color-border);
    font-size: 0.85rem;
    color: var(--color-text-muted);
    text-align: right;
}

.sem-earned {
    color: var(--color-accent-primary);
    font-weight: 600;
}

.year-progress {
    margin-top: var(--space-md);
    height: 4px;
    background: var(--color-bg-tertiary);
    border-radius: 2px;
    overflow: hidden;
}

.year-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--color-accent-primary), var(--color-accent-secondary));
    border-radius: 2px;
    width: 0%;
    transition: width 0.5s ease;
}

/* Summary Panel */
.summary-panel {
    background: linear-gradient(145deg, var(--color-accent-primary), #6B5CE7);
    border-radius: 24px;
    padding: var(--space-xl);
    color: white;
}

.summary-title {
    font-family: var(--font-display);
    font-size: 1.5rem;
    margin-bottom: var(--space-lg);
    text-align: center;
}

.summary-stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-lg);
    margin-bottom: var(--space-lg);
}

.stat-item {
    text-align: center;
}

.stat-value {
    display: block;
    font-family: var(--font-display);
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--space-xs);
}

.stat-label {
    font-size: 0.85rem;
    opacity: 0.8;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.summary-progress {
    height: 12px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 6px;
    overflow: hidden;
    margin-bottom: var(--space-md);
}

.summary-bar {
    height: 100%;
    background: white;
    border-radius: 6px;
    width: 0%;
    transition: width 0.5s ease;
}

.summary-status {
    text-align: center;
    font-size: 1rem;
    opacity: 0.9;
}

/* Curriculum Section */
.curriculum-section {
    padding: var(--space-3xl) var(--space-xl);
}

.curriculum-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-lg);
}

.cur-card {
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: 20px;
    padding: var(--space-xl);
    transition: all var(--transition-medium);
    position: relative;
    overflow: hidden;
}

.cur-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, var(--color-accent-primary), var(--color-accent-secondary));
    transform: scaleX(0);
    transition: transform var(--transition-medium);
}

.cur-card:hover {
    transform: translateY(-8px);
    border-color: var(--color-accent-primary);
    box-shadow: 0 20px 60px rgba(123, 104, 238, 0.15);
}

.cur-card:hover::before {
    transform: scaleX(1);
}

.cur-icon {
    font-family: var(--font-display);
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-accent-primary);
    opacity: 0.3;
    margin-bottom: var(--space-md);
}

.cur-title {
    font-family: var(--font-display);
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: var(--space-sm);
}

.cur-desc {
    font-size: 0.9rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--space-md);
    line-height: 1.6;
}

.cur-list {
    list-style: none;
}

.cur-list li {
    font-size: 0.85rem;
    color: var(--color-text-muted);
    padding: var(--space-xs) 0;
    padding-left: var(--space-md);
    position: relative;
}

.cur-list li::before {
    content: '◆';
    position: absolute;
    left: 0;
    color: var(--color-accent-primary);
    font-size: 0.6rem;
}

/* About Section */
.about-section {
    background: var(--color-bg-secondary);
    border-radius: 32px;
    margin: var(--space-xl) auto;
}

.about-content {
    max-width: 800px;
    margin: 0 auto;
}

.about-text {
    margin-bottom: var(--space-xl);
}

.about-text p {
    color: var(--color-text-secondary);
    font-size: 1.1rem;
    line-height: 1.8;
    margin-bottom: var(--space-md);
}

.about-features {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-md);
}

.feature {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-md);
    background: var(--color-bg-primary);
    border: 1px solid var(--color-border);
    border-radius: 12px;
    transition: all var(--transition-fast);
}

.feature:hover {
    border-color: var(--color-accent-primary);
    background: rgba(123, 104, 238, 0.05);
}

.feature-icon {
    color: var(--color-accent-primary);
    font-size: 1.2rem;
}

.feature-text {
    font-size: 0.95rem;
    color: var(--color-text-primary);
}

/* Footer */
.footer {
    border-top: 1px solid var(--color-border);
    padding: var(--space-xl);
    margin-top: var(--space-3xl);
}

.footer-content {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
}

.footer-text {
    color: var(--color-text-muted);
    font-size: 0.9rem;
}

/* Responsive Design */
@media (max-width: 1200px) {
    .calculator-grid {
        grid-template-columns: 1fr;
    }
    
    .curriculum-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 900px) {
    .hero {
        grid-template-columns: 1fr;
        text-align: center;
        padding-top: calc(var(--space-3xl) + 6rem);
    }
    
    .hero-subtitle {
        margin-left: auto;
        margin-right: auto;
    }
    
    .hero-cta {
        justify-content: center;
    }
    
    .hero-visual {
        order: -1;
    }
    
    .credit-card {
        width: 280px;
    }
    
    .summary-stats {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 600px) {
    .navbar {
        padding: var(--space-sm) var(--space-md);
    }
    
    .nav-links {
        gap: var(--space-md);
    }
    
    .nav-link {
        font-size: 0.8rem;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .semesters {
        grid-template-columns: 1fr;
    }
    
    .curriculum-grid {
        grid-template-columns: 1fr;
    }
    
    .about-features {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        flex-direction: column;
        gap: var(--space-md);
        text-align: center;
    }
    
    .calculator-section {
        padding: var(--space-xl) var(--space-md);
    }
}

/* Scroll Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.year-block {
    animation: fadeInUp 0.6s ease forwards;
    opacity: 0;
}

.year-block:nth-child(1) { animation-delay: 0.1s; }
.year-block:nth-child(2) { animation-delay: 0.2s; }
.year-block:nth-child(3) { animation-delay: 0.3s; }
.year-block:nth-child(4) { animation-delay: 0.4s; }

.cur-card {
    animation: fadeInUp 0.6s ease forwards;
    opacity: 0;
}

.cur-card:nth-child(1) { animation-delay: 0.1s; }
.cur-card:nth-child(2) { animation-delay: 0.2s; }
.cur-card:nth-child(3) { animation-delay: 0.3s; }
.cur-card:nth-child(4) { animation-delay: 0.4s; }