/* =============================================
   AI SELTZËRS - PREMIUM MINIMALIST STYLESHEET
   ============================================= */

/* =============================================
   RESET & BASE STYLES
   ============================================= */

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

:root {
    /* Colors */
    --matte-black: #1a1a1a;
    --deep-charcoal: #2d2d2d;
    --soft-charcoal: #3f3f3f;
    --warm-white: #f8f8f6;
    --light-gray: #e8e8e6;
    --mid-gray: #c4c4c2;
    --subtle-gold: #d4c5a9;
    --deep-olive: #6b7266;
    
    /* Typography - with system font fallbacks */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
    
    /* Spacing */
    --section-padding: 120px;
    --section-padding-mobile: 60px;
    --container-max: 1200px;
    
    /* Transitions */
    --transition-smooth: 800ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-fast: 400ms cubic-bezier(0.4, 0, 0.2, 1);
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-primary);
    font-size: 18px;
    line-height: 1.6;
    color: var(--matte-black);
    background-color: var(--warm-white);
    letter-spacing: 0.01em;
}

/* =============================================
   UTILITY CLASSES
   ============================================= */

.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 40px;
}

@media (max-width: 768px) {
    .container {
        padding: 0 24px;
    }
}

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

@media (max-width: 768px) {
    .section {
        padding: var(--section-padding-mobile) 0;
    }
}

.section-light {
    background-color: var(--warm-white);
    color: var(--matte-black);
}

.section-dark {
    background-color: var(--matte-black);
    color: var(--warm-white);
    background-image: radial-gradient(circle at 50% 50%, var(--deep-charcoal) 0%, var(--matte-black) 100%);
}

.emphasis {
    font-weight: 500;
    margin-top: 1.5em;
}

/* Fade-in on scroll */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity var(--transition-smooth), transform var(--transition-smooth);
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* =============================================
   NAVIGATION
   ============================================= */

.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background-color: rgba(26, 26, 26, 0.95);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    transition: background-color var(--transition-fast);
}

.nav-container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 20px 40px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    font-size: 20px;
    font-weight: 500;
    color: var(--warm-white);
    text-decoration: none;
    letter-spacing: -0.01em;
    transition: opacity var(--transition-fast);
}

.nav-logo:hover {
    opacity: 0.7;
}

.nav-links {
    display: flex;
    gap: 32px;
    align-items: center;
}

.nav-links a {
    font-size: 15px;
    color: var(--warm-white);
    text-decoration: none;
    transition: opacity var(--transition-fast);
    letter-spacing: 0.02em;
}

.nav-links a:hover {
    opacity: 0.6;
}

.nav-cta {
    padding: 8px 20px;
    background-color: transparent;
    border: 1px solid var(--mid-gray);
    border-radius: 4px;
    transition: background-color var(--transition-fast), border-color var(--transition-fast);
}

.nav-cta:hover {
    background-color: rgba(255, 255, 255, 0.05);
    border-color: var(--warm-white);
    opacity: 1 !important;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.nav-toggle span {
    width: 24px;
    height: 2px;
    background-color: var(--warm-white);
    margin: 3px 0;
    transition: all var(--transition-fast);
}

@media (max-width: 768px) {
    .nav-container {
        padding: 16px 24px;
    }
    
    .nav-links {
        position: fixed;
        top: 60px;
        left: 0;
        right: 0;
        background-color: var(--matte-black);
        flex-direction: column;
        gap: 0;
        padding: 24px;
        transform: translateY(-100%);
        opacity: 0;
        transition: transform var(--transition-fast), opacity var(--transition-fast);
        pointer-events: none;
    }
    
    .nav-links.active {
        transform: translateY(0);
        opacity: 1;
        pointer-events: all;
    }
    
    .nav-links a {
        padding: 12px 0;
        width: 100%;
        text-align: center;
    }
    
    .nav-toggle {
        display: flex;
    }
}

/* =============================================
   HERO SECTION
   ============================================= */

.hero {
    min-height: 100vh;
    background-color: var(--matte-black);
    background-image: radial-gradient(circle at 50% 30%, var(--deep-charcoal) 0%, var(--matte-black) 70%);
    display: flex;
    align-items: center;
    padding-top: 80px;
}

.hero-container {
    display: grid;
    grid-template-columns: 1fr 1.2fr;
    gap: 80px;
    align-items: center;
}

.hero-content {
    color: var(--warm-white);
}

.hero-title {
    font-size: 72px;
    font-weight: 300;
    letter-spacing: -0.02em;
    line-height: 1.1;
    margin-bottom: 16px;
}

.hero-tagline {
    font-size: 42px;
    font-weight: 400;
    letter-spacing: -0.01em;
    margin-bottom: 32px;
    color: var(--light-gray);
}

.hero-description {
    font-size: 20px;
    line-height: 1.5;
    color: var(--mid-gray);
    margin-bottom: 48px;
    max-width: 480px;
}

.hero-cta {
    display: inline-block;
    font-size: 16px;
    color: var(--warm-white);
    text-decoration: none;
    opacity: 0.8;
    transition: opacity var(--transition-fast);
    letter-spacing: 0.02em;
}

.hero-cta:hover {
    opacity: 1;
}

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

.product-hero-img {
    max-width: 100%;
    height: auto;
    filter: drop-shadow(0 20px 60px rgba(0, 0, 0, 0.4));
    animation: fadeInUp 1.2s cubic-bezier(0.4, 0, 0.2, 1);
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(40px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@media (max-width: 1024px) {
    .hero-title {
        font-size: 56px;
    }
    
    .hero-tagline {
        font-size: 32px;
    }
    
    .hero-container {
        gap: 60px;
    }
}

@media (max-width: 768px) {
    .hero {
        padding-top: 60px;
        min-height: auto;
        padding-bottom: 60px;
    }
    
    .hero-container {
        grid-template-columns: 1fr;
        gap: 48px;
    }
    
    .hero-title {
        font-size: 48px;
    }
    
    .hero-tagline {
        font-size: 28px;
    }
    
    .hero-description {
        font-size: 18px;
    }
}

/* =============================================
   TWO-COLUMN LAYOUT (COGNITIVE HYDRATION)
   ============================================= */

.two-column {
    display: grid;
    grid-template-columns: 40% 60%;
    gap: 80px;
}

.section-header {
    font-size: 42px;
    font-weight: 400;
    letter-spacing: -0.01em;
    line-height: 1.2;
}

.section-body p {
    margin-bottom: 1.5em;
}

.section-body p:last-child {
    margin-bottom: 0;
}

@media (max-width: 768px) {
    .two-column {
        grid-template-columns: 1fr;
        gap: 32px;
    }
    
    .section-header {
        font-size: 32px;
    }
}

/* =============================================
   SIDE PANEL LAYOUT (COGNÉVIAN)
   ============================================= */

.cognevian-section {
    position: relative;
}

.side-panel-layout {
    display: grid;
    grid-template-columns: 35% 1px 65%;
    gap: 60px;
    align-items: center;
}

.panel-left {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    padding-right: 40px;
}

.cognevian-title {
    font-size: 48px;
    font-weight: 400;
    letter-spacing: -0.01em;
    color: var(--subtle-gold);
    text-shadow: 0 0 40px rgba(212, 197, 169, 0.2);
}

.panel-divider {
    width: 1px;
    height: 200px;
    background: linear-gradient(to bottom, 
        transparent 0%, 
        var(--mid-gray) 50%, 
        transparent 100%);
}

.panel-right {
    padding-left: 40px;
}

.cognevian-body p {
    margin-bottom: 1.5em;
}

.cognevian-body p:last-child {
    margin-bottom: 0;
}

@media (max-width: 768px) {
    .side-panel-layout {
        grid-template-columns: 1fr;
        gap: 32px;
    }
    
    .panel-left {
        justify-content: flex-start;
        padding-right: 0;
    }
    
    .cognevian-title {
        font-size: 36px;
    }
    
    .panel-divider {
        display: none;
    }
    
    .panel-right {
        padding-left: 0;
    }
}

/* =============================================
   FOUR-COLUMN GRID (DAILY USE)
   ============================================= */

.section-header-centered {
    font-size: 42px;
    font-weight: 400;
    letter-spacing: -0.01em;
    text-align: center;
    margin-bottom: 80px;
}

.four-column-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 48px;
}

.time-block {
    text-align: left;
}

.time-label {
    display: block;
    font-size: 14px;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--mid-gray);
    margin-bottom: 16px;
}

.time-headline {
    font-size: 24px;
    font-weight: 500;
    margin-bottom: 12px;
    line-height: 1.3;
}

.time-description {
    font-size: 16px;
    line-height: 1.6;
    color: var(--soft-charcoal);
}

@media (max-width: 1024px) {
    .four-column-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 40px;
    }
}

@media (max-width: 768px) {
    .section-header-centered {
        font-size: 32px;
        margin-bottom: 48px;
    }
    
    .four-column-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }
}

/* =============================================
   CENTERED COLUMN (WHY DIFFERENT)
   ============================================= */

.centered-column {
    max-width: 720px;
    margin: 0 auto;
    text-align: center;
}

.why-body {
    margin-top: 48px;
}

.why-body p {
    margin-bottom: 1.5em;
}

.em-dash-list {
    list-style: none;
    margin: 2em 0;
    padding: 0;
}

.em-dash-list li {
    position: relative;
    padding-left: 1.5em;
    margin-bottom: 0.8em;
}

.em-dash-list li:before {
    content: "—";
    position: absolute;
    left: 0;
    color: var(--mid-gray);
}

@media (max-width: 768px) {
    .centered-column {
        max-width: 100%;
    }
}

/* =============================================
   PRODUCT SECTION
   ============================================= */

.product-section {
    background: linear-gradient(to bottom, var(--warm-white) 0%, var(--light-gray) 100%);
}

.product-card {
    max-width: 480px;
    margin: 0 auto;
    background-color: #ffffff;
    padding: 60px 40px;
    text-align: center;
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.08);
    border-radius: 2px;
}

.product-image {
    margin-bottom: 32px;
}

.product-img {
    max-width: 280px;
    height: auto;
}

.product-name {
    font-size: 24px;
    font-weight: 500;
    margin-bottom: 16px;
}

.product-description {
    font-size: 16px;
    line-height: 1.6;
    color: var(--soft-charcoal);
    margin-bottom: 24px;
}

.product-specs {
    font-size: 14px;
    color: var(--mid-gray);
    margin-bottom: 32px;
}

.product-specs p {
    margin: 4px 0;
}

.product-cta {
    display: inline-block;
    font-size: 16px;
    color: var(--matte-black);
    text-decoration: none;
    padding: 12px 32px;
    border: 1px solid var(--matte-black);
    border-radius: 4px;
    transition: background-color var(--transition-fast), color var(--transition-fast);
    letter-spacing: 0.02em;
}

.product-cta:hover {
    background-color: var(--matte-black);
    color: var(--warm-white);
}

@media (max-width: 768px) {
    .product-card {
        padding: 48px 24px;
    }
}

/* =============================================
   CLOSING SECTION
   ============================================= */

.closing-section {
    padding: 180px 0;
    background-image: radial-gradient(circle at 50% 50%, var(--deep-charcoal) 0%, var(--matte-black) 100%);
}

.closing-content {
    max-width: 640px;
}

.closing-headline {
    font-size: 48px;
    font-weight: 400;
    letter-spacing: -0.01em;
    margin-bottom: 48px;
}

.closing-body {
    margin-bottom: 48px;
}

.closing-body p {
    margin-bottom: 1.2em;
}

.closing-cta {
    display: inline-block;
    font-size: 18px;
    color: var(--warm-white);
    text-decoration: none;
    opacity: 0.9;
    transition: opacity var(--transition-fast), transform var(--transition-fast);
    letter-spacing: 0.02em;
}

.closing-cta:hover {
    opacity: 1;
    transform: translateX(4px);
}

@media (max-width: 768px) {
    .closing-section {
        padding: 120px 0;
    }
    
    .closing-headline {
        font-size: 36px;
    }
}

/* =============================================
   FOOTER
   ============================================= */

.footer {
    background-color: var(--matte-black);
    color: var(--warm-white);
    padding: 60px 0 40px;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 40px;
}

.footer-logo {
    font-size: 20px;
    font-weight: 500;
    margin-bottom: 8px;
}

.footer-tagline {
    font-size: 14px;
    color: var(--mid-gray);
    letter-spacing: 0.02em;
}

.footer-links {
    display: flex;
    gap: 32px;
}

.footer-links a {
    font-size: 15px;
    color: var(--mid-gray);
    text-decoration: none;
    transition: color var(--transition-fast);
    letter-spacing: 0.02em;
}

.footer-links a:hover {
    color: var(--warm-white);
}

.footer-bottom {
    padding-top: 32px;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    text-align: center;
}

.footer-bottom p {
    font-size: 14px;
    color: var(--mid-gray);
}

@media (max-width: 768px) {
    .footer-content {
        flex-direction: column;
        gap: 32px;
    }
    
    .footer-links {
        flex-direction: column;
        gap: 16px;
    }
}