/* ========================================
   LIQUID KNOWLEDGE DESIGN SYSTEM
   PDFAI Tools - Premium AI Study Experience
   ======================================== */

/* ===== FONT IMPORTS ===== */
@import url('https://fonts.googleapis.com/css2?family=Crimson+Pro:wght@400;500;600;700;800&family=Manrope:wght@400;500;600;700;800&display=swap');

/* ===== CSS RESET & BASE ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* TYPOGRAPHY - Premium Serif + Modern Sans */
    --font-display: 'Crimson Pro', Georgia, serif;
    --font-body: 'Manrope', -apple-system, system-ui, sans-serif;

    /* COLORS - Liquid Knowledge Palette */
    --color-primary: #2D3FE2;        /* Deep Blue */
    --color-secondary: #7B3FF2;      /* Rich Purple */
    --color-accent: #FF6B35;         /* Warm Orange */
    --color-success: #06D6A0;        /* Teal Success */
    --color-warning: #FFD23F;        /* Golden Yellow */

    /* GRADIENTS - Mesh & Flow */
    --gradient-hero: radial-gradient(
        circle at 20% 50%,
        rgba(45, 63, 226, 0.15) 0%,
        transparent 50%
    ),
    radial-gradient(
        circle at 80% 80%,
        rgba(123, 63, 242, 0.12) 0%,
        transparent 50%
    ),
    radial-gradient(
        circle at 40% 20%,
        rgba(255, 107, 53, 0.08) 0%,
        transparent 40%
    );

    --gradient-card: linear-gradient(
        135deg,
        rgba(255, 255, 255, 0.95) 0%,
        rgba(255, 255, 255, 0.85) 100%
    );

    --gradient-text: linear-gradient(
        120deg,
        #2D3FE2 0%,
        #7B3FF2 50%,
        #FF6B35 100%
    );

    --gradient-study: linear-gradient(
        135deg,
        #06D6A0 0%,
        #2D3FE2 100%
    );

    /* BACKGROUNDS */
    --bg-primary: #FAFBFD;
    --bg-secondary: #FFFFFF;
    --bg-tertiary: #F5F7FA;
    --bg-dark: #1A1D2E;
    --bg-card: rgba(255, 255, 255, 0.9);

    /* TEXT COLORS */
    --text-primary: #1A1D2E;
    --text-secondary: #6B7280;
    --text-tertiary: #9CA3AF;
    --text-light: #D1D5DB;
    --text-white: #FFFFFF;
    --text-gradient: var(--gradient-text);

    /* GLASSMORPHISM */
    --glass-bg: rgba(255, 255, 255, 0.7);
    --glass-border: rgba(255, 255, 255, 0.8);
    --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.06);
    --glass-blur: blur(16px);

    /* SHADOWS - Elevated & Soft */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.08);
    --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.10);
    --shadow-glow: 0 0 24px rgba(45, 63, 226, 0.15);

    /* SPACING */
    --spacing-xs: 8px;
    --spacing-sm: 16px;
    --spacing-md: 24px;
    --spacing-lg: 40px;
    --spacing-xl: 64px;
    --spacing-2xl: 96px;

    /* BORDER RADIUS */
    --radius-sm: 8px;
    --radius-md: 16px;
    --radius-lg: 24px;
    --radius-xl: 32px;
    --radius-full: 9999px;

    /* TRANSITIONS */
    --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-bounce: 0.6s cubic-bezier(0.34, 1.56, 0.64, 1);

    /* Z-INDEX LAYERS */
    --z-base: 1;
    --z-dropdown: 10;
    --z-sticky: 100;
    --z-modal: 1000;
    --z-tooltip: 2000;
}

/* ===== GLOBAL STYLES ===== */
html {
    scroll-behavior: smooth;
    font-size: 16px;
}

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

/* TYPOGRAPHY SCALE */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    font-weight: 700;
    line-height: 1.2;
    letter-spacing: -0.02em;
    color: var(--text-primary);
}

h1 {
    font-size: clamp(2.5rem, 6vw, 4.5rem);
    font-weight: 800;
    letter-spacing: -0.03em;
}

h2 {
    font-size: clamp(2rem, 4vw, 3.5rem);
}

h3 {
    font-size: clamp(1.5rem, 3vw, 2.25rem);
}

h4 {
    font-size: clamp(1.25rem, 2.5vw, 1.75rem);
}

p {
    font-size: 1.125rem;
    line-height: 1.8;
    color: var(--text-secondary);
}

/* GRADIENT TEXT */
.gradient-text {
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    display: inline-block;
}

/* ===== LAYOUT UTILITIES ===== */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.container-wide {
    max-width: 1440px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.container-narrow {
    max-width: 960px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* SECTION SPACING */
.section {
    padding: var(--spacing-2xl) 0;
}

.section-lg {
    padding: 120px 0;
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.section-title {
    font-family: var(--font-display);
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 800;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
    line-height: 1.2;
}

.section-subtitle {
    font-size: clamp(1rem, 2vw, 1.25rem);
    color: var(--text-secondary);
    line-height: 1.6;
    max-width: 600px;
    margin: 0 auto;
}

/* ===== GLASS CARD SYSTEM ===== */
.glass-card {
    background: var(--glass-bg);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.glass-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
}

.glass-card-premium {
    background: var(--gradient-card);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border: 1px solid rgba(45, 63, 226, 0.1);
    box-shadow: var(--shadow-lg), 0 0 0 1px rgba(45, 63, 226, 0.05);
}

/* ===== GRADIENT MESH BACKGROUNDS ===== */
.mesh-bg {
    position: relative;
    overflow: hidden;
    background: var(--bg-primary);
}

.mesh-bg::before {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--gradient-hero);
    opacity: 1;
    z-index: 0;
    pointer-events: none;
}

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

.mesh-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.3;
    pointer-events: none;
    animation: float 20s ease-in-out infinite;
}

.mesh-orb-1 {
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(45, 63, 226, 0.4) 0%, transparent 70%);
    top: -200px;
    left: -100px;
    animation-delay: 0s;
}

.mesh-orb-2 {
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(123, 63, 242, 0.3) 0%, transparent 70%);
    top: 200px;
    right: -150px;
    animation-delay: 7s;
}

.mesh-orb-3 {
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(255, 107, 53, 0.2) 0%, transparent 70%);
    bottom: -100px;
    left: 30%;
    animation-delay: 14s;
}

@keyframes float {
    0%, 100% {
        transform: translate(0, 0) scale(1);
    }
    33% {
        transform: translate(30px, -30px) scale(1.1);
    }
    66% {
        transform: translate(-20px, 20px) scale(0.9);
    }
}

/* ===== BUTTONS ===== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    padding: 16px 32px;
    font-family: var(--font-body);
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--radius-full);
    border: none;
    cursor: pointer;
    transition: all var(--transition-base);
    text-decoration: none;
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: var(--gradient-text);
    color: white;
    box-shadow: var(--shadow-md), 0 0 0 0 rgba(45, 63, 226, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg), 0 0 24px rgba(45, 63, 226, 0.3);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-secondary {
    background: white;
    color: var(--color-primary);
    border: 2px solid var(--color-primary);
}

.btn-secondary:hover {
    background: var(--color-primary);
    color: white;
}

.btn-glass {
    background: var(--glass-bg);
    backdrop-filter: var(--glass-blur);
    color: var(--text-primary);
    border: 1px solid var(--glass-border);
}

.btn-glass:hover {
    background: white;
    box-shadow: var(--shadow-md);
}

/* ===== BADGES & PILLS ===== */
.badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    background: rgba(45, 63, 226, 0.08);
    color: var(--color-primary);
    font-size: 0.875rem;
    font-weight: 600;
    border-radius: var(--radius-full);
    backdrop-filter: blur(8px);
}

.badge-success {
    background: rgba(6, 214, 160, 0.1);
    color: var(--color-success);
}

.badge-warning {
    background: rgba(255, 210, 63, 0.15);
    color: #D4A20F;
}

.badge-accent {
    background: rgba(255, 107, 53, 0.1);
    color: var(--color-accent);
}

/* ===== FEATURE CARDS ===== */
.feature-card {
    position: relative;
    padding: var(--spacing-lg);
    background: var(--glass-bg);
    backdrop-filter: var(--glass-blur);
   -webkit-backdrop-filter: var(--glass-blur);
    border: 1px solid rgba(255, 255, 255, 0.6);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
    display: flex;
    flex-direction: column;
    height: 100%;
}

.feature-card::before {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: var(--radius-lg);
    padding: 2px;
    background: linear-gradient(135deg, rgba(45, 63, 226, 0.1), rgba(123, 63, 242, 0.05));
    -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
    mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
    -webkit-mask-composite: xor;
    mask-composite: exclude;
    opacity: 0;
    transition: opacity var(--transition-base);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
}

.feature-card:hover::before {
    opacity: 1;
}

.feature-icon {
    width: 64px;
    height: 64px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-text);
    color: white;
    font-size: 2rem;
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-sm);
    box-shadow: var(--shadow-md);
}

.feature-title {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
    line-height: 1.3;
}

.feature-description {
    font-family: var(--font-body);
    font-size: 1rem;
    line-height: 1.7;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    flex-grow: 1;
}

/* ===== STUDY STATS CARDS ===== */
.stat-card {
    padding: var(--spacing-md);
    background: white;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    border: 1px solid rgba(0, 0, 0, 0.05);
    transition: all var(--transition-base);
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.stat-value {
    font-family: var(--font-display);
    font-size: 3rem;
    font-weight: 800;
    background: var(--gradient-study);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    line-height: 1;
    margin-bottom: 8px;
}

.stat-label {
    font-size: 0.875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-tertiary);
}

/* ===== PROGRESS BARS ===== */
.progress-bar {
    height: 8px;
    background: rgba(0, 0, 0, 0.05);
    border-radius: var(--radius-full);
    overflow: hidden;
    position: relative;
}

.progress-fill {
    height: 100%;
    background: var(--gradient-study);
    border-radius: var(--radius-full);
    transition: width var(--transition-slow);
    position: relative;
    overflow: hidden;
}

.progress-fill::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(
        90deg,
        transparent 0%,
        rgba(255, 255, 255, 0.3) 50%,
        transparent 100%
    );
    animation: shimmer 2s infinite;
}

@keyframes shimmer {
    0% {
        transform: translateX(-100%);
    }
    100% {
        transform: translateX(100%);
    }
}

/* ===== ANIMATIONS ===== */
@keyframes fade-in-up {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fade-in {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes scale-in {
    from {
        opacity: 0;
        transform: scale(0.9);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

@keyframes slide-in-left {
    from {
        opacity: 0;
        transform: translateX(-30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes slide-in-right {
    from {
        opacity: 0;
        transform: translateX(30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* Animation Classes */
.animate-fade-in-up {
    animation: fade-in-up 0.6s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

.animate-fade-in {
    animation: fade-in 0.6s ease forwards;
}

.animate-scale-in {
    animation: scale-in 0.5s cubic-bezier(0.34, 1.56, 0.64, 1) forwards;
}

/* Stagger Delays */
.stagger-1 { animation-delay: 0.1s; opacity: 0; }
.stagger-2 { animation-delay: 0.2s; opacity: 0; }
.stagger-3 { animation-delay: 0.3s; opacity: 0; }
.stagger-4 { animation-delay: 0.4s; opacity: 0; }
.stagger-5 { animation-delay: 0.5s; opacity: 0; }
.stagger-6 { animation-delay: 0.6s; opacity: 0; }
.stagger-7 { animation-delay: 0.7s; opacity: 0; }
.stagger-8 { animation-delay: 0.8s; opacity: 0; }

/* ===== RESPONSIVE UTILITIES ===== */
@media (max-width: 768px) {
    :root {
        --spacing-xl: 48px;
        --spacing-2xl: 64px;
    }

    .section {
        padding: var(--spacing-xl) 0;
    }

    h1 {
        font-size: 2.5rem;
    }

    h2 {
        font-size: 2rem;
    }

    p {
        font-size: 1rem;
    }

    .glass-card {
        padding: var(--spacing-md);
    }

    .features-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }

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

    .container {
        padding: 0 var(--spacing-sm);
    }
}

/* ===== ACCESSIBILITY ===== */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus Visible */
*:focus-visible {
    outline: 3px solid var(--color-primary);
    outline-offset: 2px;
    border-radius: var(--radius-sm);
}

/* ===== SCROLLBAR STYLING ===== */
::-webkit-scrollbar {
    width: 12px;
}

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

::-webkit-scrollbar-thumb {
    background: linear-gradient(180deg, var(--color-primary), var(--color-secondary));
    border-radius: var(--radius-full);
    border: 3px solid var(--bg-tertiary);
}

::-webkit-scrollbar-thumb:hover {
    background: linear-gradient(180deg, var(--color-secondary), var(--color-primary));
}

/* ===== SELECTION ===== */
::selection {
    background: rgba(45, 63, 226, 0.2);
    color: var(--text-primary);
}

::-moz-selection {
    background: rgba(45, 63, 226, 0.2);
    color: var(--text-primary);
}

/* ===== NAVIGATION ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--glass-bg);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
    z-index: var(--z-sticky);
    transition: all var(--transition-base);
}

.nav-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    transition: transform var(--transition-fast);
}

.nav-logo:hover {
    transform: scale(1.02);
}

.logo-icon {
    width: 40px;
    height: 40px;
    border-radius: 12px;
    background-image: url('/assets/images/logo-1024.png');
    background-size: cover;
    background-position: center;
    box-shadow: var(--shadow-md);
}

.logo-name {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text-primary);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.9375rem;
    transition: color var(--transition-fast);
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-text);
    transition: width var(--transition-fast);
}

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

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

.btn-sm {
    padding: 10px 20px;
    font-size: 0.875rem;
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.mobile-menu-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    transition: all var(--transition-fast);
    border-radius: 2px;
}

.mobile-menu {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--bg-secondary);
    z-index: calc(var(--z-sticky) - 1);
    transform: translateX(100%);
    transition: transform var(--transition-base);
}

.mobile-menu.active {
    transform: translateX(0);
}

.mobile-menu-content {
    padding: 100px 2rem 2rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.mobile-menu-link {
    color: var(--text-primary);
    text-decoration: none;
    font-size: 1.25rem;
    font-weight: 600;
    padding: 1rem;
    border-radius: var(--radius-md);
    transition: background var(--transition-fast);
}

.mobile-menu-link:hover {
    background: rgba(45, 63, 226, 0.05);
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

    .mobile-menu-toggle {
        display: flex;
    }
}

/* ===== HERO SECTION ===== */
.hero {
    position: relative;
    padding: 140px 0 80px;
    overflow: hidden;
    min-height: 90vh;
    display: flex;
    align-items: center;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1.1fr 0.9fr;
    gap: var(--spacing-xl);
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero-eyebrow {
    display: inline-block;
    font-size: 0.875rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
    padding: 6px 16px;
    background: rgba(45, 63, 226, 0.08);
    border-radius: var(--radius-full);
}

.hero-title {
    margin-bottom: var(--spacing-md);
    line-height: 1.1;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
    line-height: 1.6;
}

.hero-features {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    margin-bottom: var(--spacing-lg);
}

.hero-feature {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.hero-feature-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    background: rgba(45, 63, 226, 0.08);
    border-radius: 8px;
    color: var(--color-primary);
}

.hero-badges {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-bottom: var(--spacing-lg);
}

.hero-cta {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 1rem;
}

.hero-social-proof {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 0.875rem;
    color: var(--text-tertiary);
}

.hero-rating {
    display: flex;
    align-items: center;
    gap: 6px;
}

.hero-rating .stars {
    color: #FFB800;
    letter-spacing: -2px;
}

.hero-divider {
    color: var(--text-light);
}

.btn-large {
    padding: 18px 40px;
    font-size: 1.125rem;
}

.hero-note {
    font-size: 0.875rem;
    color: var(--text-tertiary);
}

.hero-visual {
    position: relative;
}

.phone-mockup {
    max-width: 400px;
    margin: 0 auto;
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-xl);
}

.phone-mockup img {
    width: 100%;
    height: auto;
    display: block;
}

@media (max-width: 768px) {
    .hero {
        padding: 120px 0 60px;
        min-height: auto;
    }

    .hero-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }

    .hero-visual {
        order: -1;
    }

    .phone-mockup {
        max-width: 300px;
    }

    .hero-features {
        flex-direction: column;
        gap: 12px;
    }

    .hero-social-proof {
        flex-wrap: wrap;
        gap: 8px;
    }

    .hero-divider {
        display: none;
    }
}

/* ===== SECTION LABELS ===== */
.section-label {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
    padding: 6px 14px;
    background: rgba(45, 63, 226, 0.06);
    border-radius: var(--radius-full);
}

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

/* ===== HOW IT WORKS - DESKTOP OPTIMIZED ===== */
.how-works-desktop {
    padding: var(--spacing-2xl) 0;
    background: var(--bg-secondary);
}

.steps-row {
    display: flex;
    align-items: flex-start;
    justify-content: center;
    gap: var(--spacing-lg);
    max-width: 1400px;
    margin: 0 auto;
}

.step-block {
    flex: 1;
    max-width: 380px;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.step-phone {
    width: 100%;
    max-width: 280px;
    margin-bottom: var(--spacing-lg);
    border-radius: 32px;
    overflow: hidden;
    box-shadow:
        0 30px 60px -20px rgba(0, 0, 0, 0.2),
        0 0 0 1px rgba(0, 0, 0, 0.05);
    background: #0f0f1a;
    padding: 12px;
    transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.step-block:hover .step-phone {
    transform: translateY(-12px);
    box-shadow:
        0 40px 80px -25px rgba(0, 0, 0, 0.25),
        0 0 0 1px rgba(0, 0, 0, 0.05);
}

.step-phone img {
    width: 100%;
    height: auto;
    display: block;
    border-radius: 22px;
}

.step-info {
    width: 100%;
    max-width: 320px;
}

.step-number {
    width: 48px;
    height: 48px;
    margin: 0 auto var(--spacing-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #2D3FE2, #4A6CF7);
    color: white;
    font-family: var(--font-display);
    font-size: 1.375rem;
    font-weight: 800;
    border-radius: 14px;
    box-shadow: 0 8px 20px rgba(45, 63, 226, 0.25);
}

.step-number.purple {
    background: linear-gradient(135deg, #7B3FF2, #A855F7);
    box-shadow: 0 8px 20px rgba(123, 63, 242, 0.25);
}

.step-number.teal {
    background: linear-gradient(135deg, #06D6A0, #34D399);
    box-shadow: 0 8px 20px rgba(6, 214, 160, 0.25);
}

.step-info h3 {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
}

.step-info p {
    font-size: 1rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin: 0;
}

.step-arrow {
    display: flex;
    align-items: center;
    justify-content: center;
    padding-top: 140px;
    opacity: 0.4;
    flex-shrink: 0;
}

/* Responsive */
@media (max-width: 1024px) {
    .steps-row {
        flex-direction: column;
        align-items: center;
        gap: var(--spacing-xl);
    }

    .step-block {
        max-width: 400px;
    }

    .step-phone {
        max-width: 260px;
    }

    .step-arrow {
        display: none;
    }
}

@media (max-width: 480px) {
    .step-phone {
        max-width: 220px;
        padding: 8px;
        border-radius: 24px;
    }

    .step-phone img {
        border-radius: 18px;
    }

    .step-number {
        width: 40px;
        height: 40px;
        font-size: 1.125rem;
        border-radius: 12px;
    }

    .step-info h3 {
        font-size: 1.25rem;
    }
}

/* ===== FEATURES SHOWCASE ===== */
.feature-category {
    margin-bottom: var(--spacing-xl);
}

.feature-category-title {
    display: flex;
    align-items: center;
    gap: 10px;
    font-family: var(--font-body);
    font-size: 0.875rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-tertiary);
    margin-bottom: var(--spacing-md);
    padding-left: 4px;
}

.category-icon {
    width: 8px;
    height: 8px;
    border-radius: 50%;
}

.category-icon.ai-icon {
    background: var(--gradient-text);
}

.category-icon.core-icon {
    background: var(--gradient-study);
}

.category-icon.pro-icon {
    background: linear-gradient(135deg, #FF6B35 0%, #F7C59F 100%);
}

.features-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-md);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
    align-items: stretch;
}

/* Large feature cards for study page */
.feature-card-large {
    display: flex;
    flex-direction: column;
    padding: var(--spacing-lg);
    height: 100%;
}

.feature-large-content {
    flex: 1;
    display: flex;
    flex-direction: column;
}

.feature-large-title {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin: var(--spacing-sm) 0;
}

.feature-large-description {
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: var(--spacing-sm);
}

.feature-list {
    list-style: disc;
    padding-left: var(--spacing-md);
    margin: var(--spacing-sm) 0;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.feature-list li {
    margin-bottom: 4px;
}

.feature-large-visual {
    margin-top: auto;
    padding-top: var(--spacing-md);
}

.feature-large-visual .mockup-card {
    padding: var(--spacing-md);
    background: rgba(255, 255, 255, 0.5);
}

/* Flashcard demo */
.flashcard-demo .flashcard-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 4px;
}

.flashcard-demo .flashcard-text {
    font-size: 1rem;
    color: var(--text-primary);
    font-weight: 500;
    margin-bottom: var(--spacing-sm);
}

.flashcard-demo .flashcard-hint {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-style: italic;
}

/* Quiz demo */
.quiz-demo .quiz-question {
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

.quiz-demo .quiz-options {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.quiz-demo .quiz-option {
    font-size: 0.85rem;
    color: var(--text-secondary);
    padding: 6px 10px;
    background: rgba(0, 0, 0, 0.03);
    border-radius: var(--radius-sm);
}

.quiz-demo .quiz-option-correct {
    background: rgba(16, 185, 129, 0.15);
    color: #059669;
    font-weight: 500;
}

.quiz-demo .quiz-score {
    margin-top: var(--spacing-sm);
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* Stats demo */
.stats-demo {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.stats-demo .stat-item {
    display: flex;
    flex-direction: column;
}

.stats-demo .stat-label {
    font-size: 0.7rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.stats-demo .stat-value {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.feature-card {
    position: relative;
    display: flex;
    gap: var(--spacing-sm);
    padding: var(--spacing-md);
    cursor: pointer;
}

.feature-card .feature-icon {
    width: 48px;
    height: 48px;
    min-width: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-md);
    margin-bottom: 0;
}

.feature-body {
    flex: 1;
    display: flex;
    flex-direction: column;
}

.feature-card .feature-title {
    font-family: var(--font-display);
    font-size: 1.125rem;
    font-weight: 700;
    margin-bottom: 4px;
}

.feature-card .feature-description {
    font-size: 0.9375rem;
    line-height: 1.5;
    margin-bottom: var(--spacing-xs);
    flex-grow: 1;
}

/* Feature Tier Badges */
.feature-tier {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 600;
    padding: 4px 10px;
    border-radius: var(--radius-full);
    margin-top: auto;
}

.tier-free {
    background: rgba(6, 214, 160, 0.1);
    color: #059669;
}

.tier-unlimited {
    background: rgba(45, 63, 226, 0.08);
    color: var(--color-primary);
}

.tier-premium {
    background: rgba(255, 107, 53, 0.1);
    color: var(--color-accent);
}

/* Gradient Icon Variants */
.gradient-purple {
    background: linear-gradient(135deg, #7B3FF2, #BD10E0);
}

.gradient-blue {
    background: linear-gradient(135deg, #2D3FE2, #4A90E2);
}

.gradient-teal {
    background: linear-gradient(135deg, #06D6A0, #0EA5E9);
}

.gradient-orange {
    background: linear-gradient(135deg, #FF6B35, #FFD23F);
}

.gradient-teal-blue {
    background: linear-gradient(135deg, #06D6A0, #2D3FE2);
}

.gradient-blue-purple {
    background: linear-gradient(135deg, #2D3FE2, #7B3FF2);
}

.gradient-orange-yellow {
    background: linear-gradient(135deg, #FF6B35, #FFD23F);
}

.feature-meta {
    margin-top: auto;
    padding-top: var(--spacing-sm);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-sm);
}

.feature-link {
    color: var(--color-primary);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.9375rem;
    transition: color var(--transition-fast);
}

.feature-link:hover {
    color: var(--color-secondary);
}

/* ===== STUDY STATS ===== */
.study-stats {
    background: var(--bg-tertiary);
}

.stats-showcase {
    max-width: 900px;
    margin: 0 auto;
}

.stats-context {
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.stats-intro {
    font-size: 1.125rem;
    font-weight: 500;
    color: var(--text-secondary);
}

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

.stat-card {
    padding: var(--spacing-md);
    background: white;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid rgba(0, 0, 0, 0.04);
    text-align: center;
    transition: all var(--transition-base);
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.stat-card .stat-icon {
    color: var(--color-primary);
    margin-bottom: var(--spacing-xs);
}

.stat-card .stat-value {
    font-family: var(--font-display);
    font-size: 2.5rem;
    font-weight: 800;
    background: var(--gradient-study);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    line-height: 1;
    margin-bottom: 8px;
}

.stat-card .stat-label {
    font-size: 0.8125rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-tertiary);
    margin-bottom: 8px;
}

.stat-bar {
    height: 6px;
    background: rgba(0, 0, 0, 0.05);
    border-radius: var(--radius-full);
    overflow: hidden;
    margin-top: 8px;
}

.stat-bar-fill {
    height: 100%;
    background: var(--gradient-study);
    border-radius: var(--radius-full);
    transition: width 1s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Streak Card Highlight */
.stat-card-highlight {
    background: linear-gradient(135deg, #FFF7ED, #FFEDD5);
    border: 1px solid rgba(255, 107, 53, 0.2);
}

.stat-streak {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    margin-bottom: 8px;
}

.streak-flame {
    font-size: 2rem;
}

.streak-number {
    font-family: var(--font-display);
    font-size: 3rem;
    font-weight: 800;
    color: var(--color-accent);
    line-height: 1;
}

.stat-score {
    font-family: var(--font-display);
    font-size: 3rem;
    font-weight: 800;
    background: var(--gradient-study);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    line-height: 1;
    margin-bottom: 8px;
}

.stat-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 0.8125rem;
    font-weight: 600;
    color: var(--color-success);
    margin-top: 8px;
}

.stat-badge svg {
    color: #FFB800;
}

.stat-note {
    font-size: 0.8125rem;
    color: var(--text-tertiary);
    margin-top: 8px;
}

.stats-footnote {
    text-align: center;
    font-size: 0.8125rem;
    color: var(--text-tertiary);
    font-style: italic;
}

@media (max-width: 968px) {
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 480px) {
    .stats-grid {
        grid-template-columns: 1fr;
    }
}

/* ===== AUDIENCE CARDS ===== */
.audience-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-lg);
}

.audience-card {
    padding: var(--spacing-lg);
    text-align: center;
}

.audience-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto var(--spacing-md);
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(45, 63, 226, 0.06);
    border-radius: 50%;
    color: var(--color-primary);
}

.audience-emoji {
    font-size: 4rem;
    margin-bottom: var(--spacing-sm);
}

.audience-title {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
}

.audience-description {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.6;
}

.audience-features {
    list-style: none;
    text-align: left;
    padding: 0;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
}

.audience-features li {
    padding: 6px 0;
    color: var(--text-secondary);
    font-size: 0.875rem;
    display: flex;
    align-items: center;
    gap: 6px;
}

.audience-features li::before {
    content: '';
    width: 6px;
    height: 6px;
    background: var(--color-success);
    border-radius: 50%;
}

@media (max-width: 968px) {
    .audience-grid {
        grid-template-columns: 1fr;
    }

    .audience-features {
        grid-template-columns: 1fr;
    }
}

/* ===== FAQ ===== */
.faq-accordion {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    border-bottom: 1px solid rgba(0, 0, 0, 0.06);
}

.faq-item:first-child {
    border-top: 1px solid rgba(0, 0, 0, 0.06);
}

.faq-question {
    width: 100%;
    padding: var(--spacing-md) 0;
    background: none;
    border: none;
    text-align: left;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-md);
    transition: color var(--transition-fast);
}

.faq-question:hover {
    color: var(--color-primary);
}

.faq-question h3 {
    font-family: var(--font-display);
    font-size: 1.125rem;
    font-weight: 600;
    margin: 0;
    flex: 1;
}

.faq-chevron {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    background: rgba(45, 63, 226, 0.06);
    border-radius: 8px;
    color: var(--color-primary);
    transition: all var(--transition-fast);
}

.faq-question:hover .faq-chevron {
    background: rgba(45, 63, 226, 0.12);
}

.faq-question.active .faq-chevron {
    background: var(--color-primary);
    color: white;
    transform: rotate(180deg);
}

.faq-icon {
    font-size: 1.5rem;
    color: var(--color-primary);
    transition: transform var(--transition-fast);
}

.faq-question.active .faq-icon {
    transform: rotate(45deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-base);
}

.faq-answer p {
    padding-bottom: var(--spacing-md);
    color: var(--text-secondary);
    line-height: 1.7;
}

.faq-answer a {
    color: var(--color-primary);
    text-decoration: underline;
    font-weight: 500;
}

.faq-answer a:hover {
    color: var(--color-secondary);
}

/* ===== CTA SECTIONS ===== */
.section-cta {
    text-align: center;
    margin-top: var(--spacing-xl);
}

.cta-final {
    padding: var(--spacing-2xl) 0;
}

.cta-card {
    padding: var(--spacing-xl) var(--spacing-lg);
    text-align: center;
    border-radius: var(--radius-xl);
    max-width: 700px;
    margin: 0 auto;
}

.cta-title {
    font-family: var(--font-display);
    font-size: clamp(2rem, 4vw, 2.75rem);
    font-weight: 800;
    margin-bottom: var(--spacing-sm);
}

.cta-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
    line-height: 1.6;
}

.cta-features {
    display: flex;
    justify-content: center;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
    margin-top: var(--spacing-md);
}

.cta-features span {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.9375rem;
    color: var(--text-secondary);
}

.cta-features span::before {
    content: '';
    width: 8px;
    height: 8px;
    background: var(--color-success);
    border-radius: 50%;
}

/* ===== FOOTER ===== */
.footer {
    background: var(--bg-dark);
    color: var(--text-light);
    padding: var(--spacing-xl) 0 var(--spacing-md);
}

/* Footer Top - Rating & Download */
.footer-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.footer-rating {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: 16px 24px;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.rating-stars {
    display: flex;
    align-items: center;
    gap: 4px;
}

.rating-score {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 700;
    color: white;
    margin-left: 8px;
}

.rating-text {
    color: rgba(255, 255, 255, 0.7);
    font-size: 0.9375rem;
    margin: 0;
}

.footer-app-badge {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 24px;
    background: white;
    color: #000;
    border-radius: 12px;
    text-decoration: none;
    transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}

.footer-app-badge:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(255, 255, 255, 0.15);
}

.footer-app-badge svg {
    flex-shrink: 0;
}

.badge-text {
    display: flex;
    flex-direction: column;
}

.badge-small {
    font-size: 0.625rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    line-height: 1.2;
}

.badge-large {
    font-size: 1.125rem;
    font-weight: 600;
    line-height: 1.2;
}

.footer-content {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr 1fr 1fr;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.footer-brand {
    max-width: 300px;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: var(--spacing-sm);
}

.footer-logo .logo-name {
    color: white;
}

.footer-description {
    color: rgba(255, 255, 255, 0.7);
    font-size: 0.9375rem;
    line-height: 1.6;
    margin-bottom: var(--spacing-sm);
}

.footer-features-mini {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.mini-feature {
    display: inline-block;
    padding: 4px 10px;
    background: rgba(255, 255, 255, 0.08);
    border-radius: 100px;
    font-size: 0.75rem;
    color: rgba(255, 255, 255, 0.7);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-links {
    display: contents;
}

.footer-column {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.footer-title {
    font-family: var(--font-body);
    font-size: 0.875rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: white;
    margin-bottom: 8px;
}

.footer-link {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    font-size: 0.9375rem;
    transition: color var(--transition-fast);
}

.footer-link:hover {
    color: white;
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.footer-copyright {
    color: rgba(255, 255, 255, 0.5);
    font-size: 0.875rem;
    margin: 0;
}

.footer-bottom-links {
    display: flex;
    align-items: center;
    gap: 8px;
}

.footer-bottom-link {
    color: rgba(255, 255, 255, 0.5);
    text-decoration: none;
    font-size: 0.875rem;
    transition: color var(--transition-fast);
}

.footer-bottom-link:hover {
    color: white;
}

.footer-divider {
    color: rgba(255, 255, 255, 0.3);
}

@media (max-width: 968px) {
    .footer-top {
        flex-direction: column;
        align-items: stretch;
    }

    .footer-rating {
        justify-content: center;
        flex-wrap: wrap;
        text-align: center;
    }

    .footer-app-badge {
        justify-content: center;
    }

    .footer-content {
        grid-template-columns: 1fr 1fr;
        gap: var(--spacing-md);
    }

    .footer-brand {
        max-width: 100%;
        grid-column: 1 / -1;
        text-align: center;
    }

    .footer-features-mini {
        justify-content: center;
    }

    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .footer-content {
        grid-template-columns: 1fr;
    }

    .footer-column {
        text-align: center;
    }
}