/* =====================================================
   THE METABOLIC EQUATION - Main Stylesheet
   ===================================================== */

/* ----- CSS Variables ----- */
:root {
    --color-primary: #1F73B7;
    --color-primary-dark: #14558A;
    --color-primary-light: #4A95D1;
    --color-secondary: #F3C56A;
    --color-secondary-light: #F8DFA4;
    --color-accent: #F3C56A;
    --color-text: #22303A;
    --color-text-light: #5F6E78;
    --color-background: #F6F0E4;
    --color-white: #FFFFFF;
    --color-border: #E4D9C8;
    --color-success: #1CA56A;
    --color-warning: #E5A737;
    --color-danger: #DC3545;

    --font-heading: 'Merriweather', Georgia, serif;
    --font-body: 'Open Sans', -apple-system, BlinkMacSystemFont, sans-serif;

    --shadow-sm: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 25px rgba(0,0,0,0.15);

    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 16px;

    --transition: all 0.3s ease;
}

/* ----- Reset & Base ----- */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-background);
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    line-height: 1.3;
    color: var(--color-text);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

@media (max-width: 768px) {
    h1 { font-size: 2rem; }
    h2 { font-size: 1.75rem; }
    h3 { font-size: 1.25rem; }
}

p {
    margin-bottom: 1rem;
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: var(--transition);
}

a:hover {
    color: var(--color-primary-dark);
}

img {
    max-width: 100%;
    height: auto;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* ----- Buttons ----- */
.btn {
    display: inline-block;
    padding: 0.875rem 1.75rem;
    font-family: var(--font-body);
    font-size: 1rem;
    font-weight: 600;
    text-align: center;
    text-decoration: none;
    border: 2px solid transparent;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition);
}

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

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

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

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

.btn-accent {
    background-color: var(--color-secondary);
    color: var(--color-text);
    border-color: var(--color-secondary);
}

.btn-accent:hover {
    background-color: var(--color-secondary-light);
    border-color: var(--color-secondary-light);
}

/* ----- Navigation ----- */
.main-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: var(--color-white);
    box-shadow: var(--shadow-sm);
    z-index: 1000;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 1.5rem;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-family: var(--font-heading);
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-primary);
}

.logo-icon-image {
    width: 2.15rem;
    height: 1.9rem;
    display: block;
    flex-shrink: 0;
    object-fit: cover;
    border-radius: 0.45rem;
    border: 1px solid rgba(255, 255, 255, 0.7);
    filter: drop-shadow(0 4px 10px rgba(30, 45, 58, 0.22));
    transition: transform 0.22s ease;
}

.logo:hover .logo-icon-image {
    transform: translateY(-1px) scale(1.03);
}

@media (max-width: 768px) {
    .logo-icon-image {
        width: 1.95rem;
        height: 1.72rem;
    }
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 2rem;
    list-style: none;
}

.nav-links a {
    color: var(--color-text);
    font-weight: 500;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--color-primary);
}

.btn-nav {
    background-color: var(--color-primary);
    color: var(--color-white) !important;
    padding: 0.5rem 1rem;
    border-radius: var(--radius-md);
}

.btn-nav:hover {
    background-color: var(--color-primary-dark);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--color-text);
    transition: var(--transition);
}

@media (max-width: 900px) {
    .nav-toggle {
        display: flex;
    }

    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        flex-direction: column;
        background-color: var(--color-white);
        padding: 1rem;
        box-shadow: var(--shadow-md);
        gap: 1rem;
    }

    .nav-links.active {
        display: flex;
    }
}

/* ----- Hero Section ----- */
.hero {
    padding: 8rem 1.5rem 4rem;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    color: var(--color-white);
    text-align: center;
}

.hero-content {
    max-width: 800px;
    margin: 0 auto 3rem;
}

.hero h1 {
    color: var(--color-white);
    margin-bottom: 1rem;
    font-size: 3rem;
}

.hero-subtitle {
    font-size: 1.25rem;
    opacity: 0.9;
    margin-bottom: 2rem;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.hero-app-link {
    margin-top: 0.9rem;
    text-align: center;
}

.hero-app-card {
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    gap: 0.45rem;
    text-decoration: none;
}

.hero-app-logo {
    width: 64px;
    height: 64px;
    border-radius: 14px;
    border: 1px solid rgba(255,255,255,0.35);
    box-shadow: 0 8px 20px rgba(0,0,0,0.22);
}

.hero-app-caption {
    color: var(--color-white);
    text-decoration: underline;
    text-underline-offset: 2px;
    font-weight: 600;
}

.hero-app-card:hover .hero-app-caption {
    color: var(--color-secondary-light);
}

.hero .btn-primary {
    background-color: var(--color-secondary);
    border-color: var(--color-secondary);
    color: var(--color-text);
}

.hero .btn-primary:hover {
    background-color: var(--color-secondary-light);
    border-color: var(--color-secondary-light);
}

.hero .btn-secondary {
    border-color: var(--color-white);
    color: var(--color-white);
}

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

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 3rem;
    flex-wrap: wrap;
}

.stat {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-secondary);
}

.stat-label {
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    opacity: 0.8;
}

@media (max-width: 768px) {
    .hero {
        padding: 6rem 1rem 3rem;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .hero-stats {
        gap: 1.5rem;
    }

    .stat-number {
        font-size: 2rem;
    }
}

/* ----- Section Styles ----- */
section {
    padding: 5rem 0;
}

.section-intro {
    max-width: 700px;
    margin: 0 auto 3rem;
    text-align: center;
    color: var(--color-text-light);
    font-size: 1.125rem;
}

section h2 {
    text-align: center;
    margin-bottom: 1rem;
}

/* ----- Equation Section ----- */
.equation-section {
    background-color: var(--color-white);
}

.equation-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.equation-card {
    background-color: var(--color-background);
    padding: 1.5rem;
    border-radius: var(--radius-md);
    text-align: center;
    transition: var(--transition);
}

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

.card-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.equation-card h3 {
    margin-bottom: 0.5rem;
    color: var(--color-primary);
}

.equation-card p {
    font-size: 0.9rem;
    color: var(--color-text-light);
    margin-bottom: 0;
}

/* ----- Meal Plan Preview ----- */
.meal-plan-preview {
    background-color: var(--color-background);
}

.week-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.week-card {
    background-color: var(--color-white);
    padding: 2rem;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    text-decoration: none;
    color: var(--color-text);
    border: 2px solid transparent;
}

.week-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-primary-light);
}

.week-number {
    display: inline-block;
    background-color: var(--color-primary);
    color: var(--color-white);
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.week-card h3 {
    margin-bottom: 0.5rem;
}

.week-card p {
    color: var(--color-text-light);
    margin-bottom: 1rem;
}

.week-menu-links {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.week-menu-links a {
    color: var(--color-primary);
    text-decoration: underline;
    text-underline-offset: 2px;
    font-weight: 600;
    font-size: 0.95rem;
}

.week-menu-links a:hover {
    color: var(--color-primary-dark);
}

.cta-center {
    text-align: center;
}

/* ----- About Section ----- */
.about-section {
    background-color: var(--color-white);
}

.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

@media (max-width: 900px) {
    .about-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
}

.about-text h2 {
    text-align: left;
    margin-bottom: 1.5rem;
}

.about-text p {
    color: var(--color-text-light);
}

.about-text strong {
    color: var(--color-text);
}

.signature {
    font-family: var(--font-heading);
    font-style: italic;
    color: var(--color-primary);
    margin-top: 1.5rem;
}

.book-preview {
    display: flex;
    justify-content: center;
}

.book-cover {
    width: 250px;
    height: 350px;
    background:
        radial-gradient(circle at 75% 12%, rgba(255, 255, 255, 0.2) 0%, rgba(255, 255, 255, 0) 35%),
        linear-gradient(155deg, #0a365b 0%, #144f82 42%, #0c2942 100%);
    border-radius: 4px 9px 9px 4px;
    box-shadow:
        -9px 12px 28px rgba(0, 0, 0, 0.24),
        0 2px 10px rgba(0, 0, 0, 0.18);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 2rem;
    text-align: center;
    color: var(--color-white);
    border: 1px solid rgba(255, 255, 255, 0.14);
    position: relative;
    overflow: hidden;
    isolation: isolate;
}

.book-cover::before {
    content: "";
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 14px;
    background: linear-gradient(90deg, #081d2f 0%, #113653 100%);
    border-radius: 3px 0 0 3px;
    z-index: 1;
}

.book-cover::after {
    content: "";
    position: absolute;
    inset: 16% 12% 20% 16%;
    background-image: url("../images/app-icon.jpg");
    background-size: contain;
    background-repeat: no-repeat;
    background-position: center;
    opacity: 0.14;
    mix-blend-mode: screen;
    z-index: 1;
}

.book-title {
    font-family: var(--font-heading);
    font-size: 1.45rem;
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.15;
    z-index: 1;
    position: relative;
    text-shadow: 0 2px 8px rgba(5, 22, 36, 0.4);
}

.book-subtitle {
    font-size: 0.85rem;
    color: #d7e9fb;
    z-index: 1;
    position: relative;
    text-shadow: 0 1px 6px rgba(5, 22, 36, 0.3);
}

.book-preview .cover-kicker {
    margin: 0 0 0.55rem;
    color: #d9ebff;
    font-size: 0.68rem;
    letter-spacing: 1.45px;
    text-transform: uppercase;
    font-weight: 700;
    z-index: 2;
    position: relative;
}

.book-preview .book-cover h2 {
    color: var(--color-white);
    margin: 0 0 0.75rem;
    font-size: 1.34rem;
    line-height: 1.14;
    max-width: 210px;
    z-index: 2;
    position: relative;
    text-shadow: 0 2px 8px rgba(5, 22, 36, 0.4);
}

.book-preview .book-cover h2 .cover-line {
    display: inline-block;
    white-space: nowrap;
}

.book-preview .cover-subline {
    margin: 0;
    color: rgba(232, 242, 255, 0.9);
    font-size: 0.78rem;
    line-height: 1.3;
    max-width: 210px;
    z-index: 2;
    position: relative;
    text-shadow: 0 1px 6px rgba(5, 22, 36, 0.3);
}

.book-preview .cover-divider {
    width: 56px;
    height: 2px;
    background: linear-gradient(90deg, #c8def5 0%, rgba(200, 222, 245, 0) 100%);
    margin: auto 0 0.75rem;
    z-index: 2;
    position: relative;
}

.book-preview .cover-author {
    margin: 0 0 0.18rem;
    color: #f3f8ff;
    font-size: 0.74rem;
    letter-spacing: 1.35px;
    text-transform: uppercase;
    font-weight: 700;
    z-index: 2;
    position: relative;
}

.book-preview .cover-credential {
    margin: 0;
    color: rgba(222, 236, 252, 0.84);
    font-size: 0.68rem;
    letter-spacing: 0.35px;
    z-index: 2;
    position: relative;
}

/* ----- Quick Links Section ----- */
.quick-links {
    background-color: var(--color-background);
}

.links-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 1.5rem;
}

.quick-link {
    display: block;
    background-color: var(--color-white);
    padding: 2rem;
    border-radius: var(--radius-md);
    text-align: center;
    transition: var(--transition);
    text-decoration: none;
    border: 2px solid var(--color-border);
}

.quick-link:hover {
    border-color: var(--color-primary);
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.link-icon {
    font-size: 2.5rem;
    display: block;
    margin-bottom: 1rem;
}

.quick-link h3 {
    color: var(--color-primary);
    margin-bottom: 0.5rem;
}

.quick-link p {
    font-size: 0.9rem;
    color: var(--color-text-light);
    margin-bottom: 0;
}

/* ----- Advice Section ----- */
.advice-section {
    background:
        radial-gradient(circle at 12% 22%, rgba(15, 76, 129, 0.12) 0%, rgba(15, 76, 129, 0) 40%),
        radial-gradient(circle at 88% 78%, rgba(212, 168, 83, 0.16) 0%, rgba(212, 168, 83, 0) 45%),
        linear-gradient(180deg, #f4f8ff 0%, #fcf8f1 100%);
}

.advice-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 1.25rem;
}

.advice-card {
    display: block;
    background-color: rgba(255, 255, 255, 0.88);
    border: 1px solid rgba(15, 76, 129, 0.2);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
    backdrop-filter: blur(2px);
    transition: var(--transition);
}

.advice-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--color-primary-light);
}

.advice-card h3 {
    color: var(--color-primary);
    margin-bottom: 0.5rem;
}

.advice-card p {
    color: var(--color-text-light);
    margin-bottom: 0;
}

/* ----- Conversation Section ----- */
.conversation-section {
    background-color: var(--color-white);
}

.discussion-topics {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin: 1.5rem 0;
}

.topic-tag {
    display: inline-block;
    background-color: rgba(15, 76, 129, 0.1);
    border: 1px solid rgba(15, 76, 129, 0.24);
    color: var(--color-primary-dark);
    padding: 0.35rem 0.7rem;
    border-radius: 999px;
    font-size: 0.85rem;
    font-weight: 600;
}

.conversation-note {
    margin-top: 1rem;
    font-size: 0.95rem;
    color: var(--color-text-light);
}

.comments-embed {
    margin-top: 1rem;
    background-color: var(--color-white);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: 1rem;
    min-height: 260px;
}

.comments-setup-note {
    color: var(--color-text-light);
    font-size: 0.95rem;
    margin: 0;
}

/* ----- App Section ----- */
.app-section {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    color: var(--color-white);
}

.app-content {
    display: grid;
    grid-template-columns: auto 1fr 1fr;
    gap: 3rem;
    align-items: center;
}

.app-icon img {
    width: 150px;
    height: 150px;
    border-radius: 32px;
    box-shadow: var(--shadow-lg);
}

.app-store-icon {
    margin-right: 0.5rem;
}

@media (max-width: 900px) {
    .app-content {
        grid-template-columns: 1fr 1fr;
        gap: 2rem;
    }

    .app-icon {
        grid-column: 1 / -1;
        text-align: center;
    }

    .app-icon img {
        width: 120px;
        height: 120px;
    }
}

@media (max-width: 768px) {
    .app-content {
        grid-template-columns: 1fr;
        gap: 2rem;
        text-align: center;
    }

    .app-icon img {
        width: 100px;
        height: 100px;
        border-radius: 24px;
    }
}

.app-text h2 {
    color: var(--color-white);
    text-align: left;
}

@media (max-width: 768px) {
    .app-text h2 {
        text-align: center;
    }
}

.app-text p {
    opacity: 0.9;
}

.app-text .btn-primary {
    background-color: var(--color-secondary);
    border-color: var(--color-secondary);
    color: var(--color-text);
}

.app-features {
    display: grid;
    gap: 1rem;
}

.feature {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.125rem;
}

.feature span {
    color: var(--color-secondary);
    font-weight: bold;
}

/* ----- Footer ----- */
.main-footer {
    background-color: var(--color-text);
    color: var(--color-white);
    padding: 4rem 0 2rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 2rem;
    margin-bottom: 3rem;
}

@media (max-width: 900px) {
    .footer-grid {
        grid-template-columns: 1fr 1fr;
    }
}

@media (max-width: 600px) {
    .footer-grid {
        grid-template-columns: 1fr;
    }
}

.footer-col h4 {
    color: var(--color-white);
    margin-bottom: 1rem;
    font-size: 1rem;
}

.footer-col p {
    font-size: 0.875rem;
    opacity: 0.8;
}

.disclaimer {
    font-size: 0.75rem !important;
    opacity: 0.6 !important;
    margin-top: 1rem;
}

.footer-col ul {
    list-style: none;
}

.footer-col li {
    margin-bottom: 0.5rem;
}

.footer-col a {
    color: var(--color-white);
    opacity: 0.8;
    font-size: 0.875rem;
}

.footer-col a:hover {
    opacity: 1;
    color: var(--color-secondary);
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255,255,255,0.1);
}

.footer-bottom p {
    font-size: 0.875rem;
    opacity: 0.6;
    margin-bottom: 0;
}

/* ----- Utility Classes ----- */
.text-center { text-align: center; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }

/* ----- Print Styles ----- */
@media print {
    .main-nav,
    .hero-buttons,
    .app-section,
    .main-footer {
        display: none;
    }

    body {
        font-size: 12pt;
        line-height: 1.4;
    }

    h1 { font-size: 24pt; }
    h2 { font-size: 18pt; }
    h3 { font-size: 14pt; }
}


.book-cover-image-wrap {
    padding: 0;
    overflow: hidden;
    background: #f3ecdf;
}

.book-cover-image-wrap::before,
.book-cover-image-wrap::after {
    display: none !important;
}

.book-cover-image {
    display: block;
    width: 100%;
    height: 100%;
    object-fit: contain;
    object-position: center center;
    border-radius: inherit;
}