/* ===============================================
   Tersane Web - Modern Static Site
   Mobile-First Responsive CSS
   =============================================== */

/* ===============================================
   RESET & BASE STYLES
   =============================================== */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    /* Colors */
    --navy: #1a3a5c;
    --steel-gray: #5a6b78;
    --white: #ffffff;
    --light-gray: #f5f7fa;
    --dark-gray: #2d3748;
    --accent: #2F855A;
    --accent-light: #48bb78;
    
    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    --font-size-5xl: 3rem;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 0.75rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    --spacing-4xl: 6rem;
    
    /* Layout */
    --container-max-width: 1200px;
    --header-height: 70px;
    
    /* Border radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 300ms ease;
    --transition-slow: 500ms ease;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--dark-gray);
    background-color: var(--white);
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    color: var(--navy);
    margin-bottom: var(--spacing-md);
}

h1 { font-size: var(--font-size-4xl); }
h2 { font-size: var(--font-size-3xl); }
h3 { font-size: var(--font-size-2xl); }
h4 { font-size: var(--font-size-xl); }
h5 { font-size: var(--font-size-lg); }
h6 { font-size: var(--font-size-base); }

p {
    margin-bottom: var(--spacing-md);
}

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

a:hover,
a:focus {
    color: var(--accent);
    outline: none;
}

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

/* ===============================================
   LAYOUT UTILITIES
   =============================================== */
.container {
    width: 100%;
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.section {
    padding: var(--spacing-4xl) 0;
}

.section--gray {
    background-color: var(--light-gray);
}

/* ===============================================
   BUTTONS
   =============================================== */
.btn {
    display: inline-block;
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: var(--font-size-base);
    font-weight: 600;
    text-align: center;
    border-radius: var(--radius-md);
    border: 2px solid transparent;
    cursor: pointer;
    transition: all var(--transition-base);
    text-decoration: none;
}

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

.btn--primary:hover,
.btn--primary:focus {
    background-color: var(--accent);
    border-color: var(--accent);
    color: var(--white);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

.btn--secondary:hover,
.btn--secondary:focus {
    background-color: var(--navy);
    color: var(--white);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn--full {
    width: 100%;
}

/* ===============================================
   HEADER & NAVIGATION
   =============================================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: var(--white);
    box-shadow: var(--shadow-sm);
    z-index: 1000;
    transition: all var(--transition-base);
}

.header.scrolled {
    box-shadow: var(--shadow-md);
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: var(--header-height);
}

.nav__logo {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--navy);
    transition: color var(--transition-fast);
}

.nav__logo:hover {
    color: var(--accent);
}

.nav__toggle {
    display: none;
    flex-direction: column;
    gap: 0.25rem;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-xs);
}

.nav__toggle-icon,
.nav__toggle-icon::before,
.nav__toggle-icon::after {
    width: 24px;
    height: 2px;
    background-color: var(--navy);
    transition: all var(--transition-base);
}

.nav__toggle-icon::before,
.nav__toggle-icon::after {
    content: '';
    display: block;
}

.nav__toggle-icon::before {
    transform: translateY(-8px);
}

.nav__toggle-icon::after {
    transform: translateY(6px);
}

.nav__list {
    display: flex;
    gap: var(--spacing-xl);
    list-style: none;
}

.nav__link {
    position: relative;
    font-weight: 500;
    color: var(--steel-gray);
    padding: var(--spacing-xs) 0;
    transition: color var(--transition-fast);
}

.nav__link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--accent);
    transition: width var(--transition-base);
}

.nav__link:hover,
.nav__link.active {
    color: var(--navy);
}

.nav__link:hover::after,
.nav__link.active::after {
    width: 100%;
}

/* Mobile Navigation */
@media screen and (max-width: 768px) {
    .nav__toggle {
        display: flex;
    }
    
    .nav__menu {
        position: fixed;
        top: var(--header-height);
        left: -100%;
        width: 100%;
        background-color: var(--white);
        box-shadow: var(--shadow-lg);
        transition: left var(--transition-base);
        padding: var(--spacing-xl) 0;
    }
    
    .nav__menu.active {
        left: 0;
    }
    
    .nav__list {
        flex-direction: column;
        gap: 0;
        padding: 0 var(--spacing-lg);
    }
    
    .nav__link {
        display: block;
        padding: var(--spacing-md) 0;
        border-bottom: 1px solid var(--light-gray);
    }
}

/* ===============================================
   HERO SECTION
   =============================================== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: linear-gradient(135deg, var(--navy) 0%, var(--steel-gray) 100%);
    padding-top: var(--header-height);
}

.hero__container {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-2xl);
    align-items: center;
}

.hero__content {
    color: var(--white);
}

.hero__title {
    font-size: var(--font-size-4xl);
    font-weight: 700;
    color: var(--white);
    margin-bottom: var(--spacing-lg);
    line-height: 1.2;
}

.hero__title-accent {
    color: var(--accent-light);
    display: block;
    margin-top: var(--spacing-sm);
}

.hero__description {
    font-size: var(--font-size-lg);
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: var(--spacing-xl);
    max-width: 600px;
}

.hero__buttons {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.hero__image-placeholder {
    width: 100%;
    height: 400px;
    background: linear-gradient(135deg, rgba(255,255,255,0.1) 0%, rgba(255,255,255,0.05) 100%);
    border-radius: var(--radius-xl);
    backdrop-filter: blur(10px);
}

@media screen and (min-width: 768px) {
    .hero__container {
        grid-template-columns: 1fr 1fr;
    }
    
    .hero__title {
        font-size: var(--font-size-5xl);
    }
}

/* ===============================================
   SECTION HEADERS
   =============================================== */
.section__header {
    text-align: center;
    margin-bottom: var(--spacing-3xl);
}

.section__header--left {
    text-align: left;
}

.section__title {
    font-size: var(--font-size-3xl);
    color: var(--navy);
    margin-bottom: var(--spacing-md);
}

.section__subtitle {
    font-size: var(--font-size-lg);
    color: var(--steel-gray);
    max-width: 600px;
    margin: 0 auto;
}

.section__header--left .section__subtitle {
    margin: 0;
}

/* ===============================================
   SERVICES SECTION
   =============================================== */
.services__grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
}

.service__card {
    background-color: var(--white);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.service__card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.service__icon {
    width: 64px;
    height: 64px;
    background: linear-gradient(135deg, var(--navy) 0%, var(--accent) 100%);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-lg);
    color: var(--white);
}

.service__title {
    font-size: var(--font-size-xl);
    color: var(--navy);
    margin-bottom: var(--spacing-md);
}

.service__description {
    color: var(--steel-gray);
    line-height: 1.7;
}

@media screen and (min-width: 640px) {
    .services__grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media screen and (min-width: 1024px) {
    .services__grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

/* ===============================================
   PROJECTS SECTION
   =============================================== */
.projects__grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-2xl);
}

.project__card {
    background-color: var(--white);
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.project__card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.project__image {
    position: relative;
    width: 100%;
    height: 250px;
    overflow: hidden;
}

.project__image-placeholder {
    width: 100%;
    height: 100%;
    transition: transform var(--transition-slow);
}

.project__card:hover .project__image-placeholder {
    transform: scale(1.1);
}

.project__overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(26, 58, 92, 0.9);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity var(--transition-base);
}

.project__card:hover .project__overlay {
    opacity: 1;
}

.project__link {
    color: var(--white);
    font-size: var(--font-size-lg);
    font-weight: 600;
    padding: var(--spacing-md) var(--spacing-xl);
    border: 2px solid var(--white);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.project__link:hover {
    background-color: var(--white);
    color: var(--navy);
}

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

.project__title {
    font-size: var(--font-size-xl);
    color: var(--navy);
    margin-bottom: var(--spacing-md);
}

.project__description {
    color: var(--steel-gray);
    margin-bottom: var(--spacing-lg);
    line-height: 1.7;
}

.project__tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.tag {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-md);
    background-color: var(--light-gray);
    color: var(--navy);
    border-radius: var(--radius-sm);
    font-size: var(--font-size-sm);
    font-weight: 500;
}

@media screen and (min-width: 768px) {
    .projects__grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media screen and (min-width: 1024px) {
    .projects__grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

/* ===============================================
   ABOUT SECTION
   =============================================== */
.about__grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-3xl);
    align-items: center;
}

.about__image-placeholder {
    width: 100%;
    height: 400px;
    background: linear-gradient(135deg, var(--navy) 0%, var(--accent) 100%);
    border-radius: var(--radius-xl);
}

.about__text {
    color: var(--steel-gray);
    font-size: var(--font-size-lg);
    line-height: 1.8;
    margin-bottom: var(--spacing-lg);
}

.about__stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: var(--spacing-xl);
    margin-top: var(--spacing-2xl);
}

.stat {
    text-align: center;
    padding: var(--spacing-lg);
    background-color: var(--light-gray);
    border-radius: var(--radius-lg);
}

.stat__number {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    color: var(--navy);
    margin-bottom: var(--spacing-xs);
}

.stat__label {
    color: var(--steel-gray);
    font-size: var(--font-size-sm);
}

@media screen and (min-width: 768px) {
    .about__grid {
        grid-template-columns: 1fr 1fr;
    }
}

/* ===============================================
   REFERENCES SECTION
   =============================================== */
.references__grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
}

.reference__card {
    background-color: var(--white);
    padding: var(--spacing-2xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

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

.reference__rating {
    color: #f6ad55;
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-md);
}

.reference__quote {
    color: var(--steel-gray);
    font-size: var(--font-size-lg);
    font-style: italic;
    line-height: 1.8;
    margin-bottom: var(--spacing-xl);
}

.reference__author {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.reference__avatar {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--navy) 0%, var(--accent) 100%);
}

.reference__name {
    font-weight: 600;
    color: var(--navy);
}

.reference__position {
    font-size: var(--font-size-sm);
    color: var(--steel-gray);
}

@media screen and (min-width: 768px) {
    .references__grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media screen and (min-width: 1024px) {
    .references__grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

/* ===============================================
   CONTACT SECTION
   =============================================== */
.contact__grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-3xl);
}

.contact__info-title {
    font-size: var(--font-size-2xl);
    color: var(--navy);
    margin-bottom: var(--spacing-md);
}

.contact__info-text {
    color: var(--steel-gray);
    font-size: var(--font-size-lg);
    line-height: 1.7;
    margin-bottom: var(--spacing-2xl);
}

.contact__methods {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xl);
}

.contact__method {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-md);
}

.contact__method-icon {
    width: 48px;
    height: 48px;
    background-color: var(--light-gray);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--navy);
    flex-shrink: 0;
}

.contact__method-label {
    font-size: var(--font-size-sm);
    color: var(--steel-gray);
    margin-bottom: var(--spacing-xs);
}

.contact__method-value {
    font-weight: 600;
    color: var(--navy);
    transition: color var(--transition-fast);
}

.contact__method-value:hover {
    color: var(--accent);
}

/* Contact Form */
.contact__form {
    background-color: var(--white);
    padding: var(--spacing-2xl);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
}

.form__group {
    display: flex;
    flex-direction: column;
}

.form__group--full {
    grid-column: 1 / -1;
}

.form__label {
    font-weight: 600;
    color: var(--navy);
    margin-bottom: var(--spacing-sm);
    font-size: var(--font-size-sm);
}

.form__input,
.form__textarea {
    padding: var(--spacing-md);
    border: 2px solid var(--light-gray);
    border-radius: var(--radius-md);
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    transition: all var(--transition-fast);
}

.form__input:focus,
.form__textarea:focus {
    outline: none;
    border-color: var(--navy);
    box-shadow: 0 0 0 3px rgba(26, 58, 92, 0.1);
}

.form__textarea {
    resize: vertical;
    min-height: 120px;
}

@media screen and (min-width: 768px) {
    .contact__grid {
        grid-template-columns: 1fr 1.2fr;
    }
    
    .contact__form {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* ===============================================
   FOOTER
   =============================================== */
.footer {
    background-color: var(--navy);
    color: var(--white);
    padding: var(--spacing-4xl) 0 var(--spacing-xl);
}

.footer__content {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-2xl);
    margin-bottom: var(--spacing-2xl);
}

.footer__logo {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--white);
    margin-bottom: var(--spacing-md);
    display: inline-block;
}

.footer__description {
    color: rgba(255, 255, 255, 0.8);
    line-height: 1.7;
    max-width: 300px;
}

.footer__links {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: var(--spacing-xl);
}

.footer__title {
    color: var(--white);
    font-size: var(--font-size-base);
    font-weight: 600;
    margin-bottom: var(--spacing-md);
}

.footer__list {
    list-style: none;
}

.footer__list li {
    margin-bottom: var(--spacing-sm);
}

.footer__link {
    color: rgba(255, 255, 255, 0.8);
    transition: color var(--transition-fast);
}

.footer__link:hover {
    color: var(--accent-light);
}

.footer__bottom {
    padding-top: var(--spacing-xl);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer__copyright {
    text-align: center;
    color: rgba(255, 255, 255, 0.6);
    font-size: var(--font-size-sm);
}

@media screen and (min-width: 768px) {
    .footer__content {
        grid-template-columns: 1.5fr 2fr;
    }
}

/* ===============================================
   ACCESSIBILITY
   =============================================== */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

/* Focus visible for keyboard navigation */
*:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

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

/* ===============================================
   UTILITIES
   =============================================== */
.text-center {
    text-align: center;
}

.text-navy {
    color: var(--navy);
}

.bg-navy {
    background-color: var(--navy);
}

.mt-1 { margin-top: var(--spacing-xs); }
.mt-2 { margin-top: var(--spacing-sm); }
.mt-3 { margin-top: var(--spacing-md); }
.mt-4 { margin-top: var(--spacing-lg); }

.mb-1 { margin-bottom: var(--spacing-xs); }
.mb-2 { margin-bottom: var(--spacing-sm); }
.mb-3 { margin-bottom: var(--spacing-md); }
.mb-4 { margin-bottom: var(--spacing-lg); }

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

.fade-in-up {
    animation: fadeInUp var(--transition-slow) ease;
}

/* Loading State */
@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

.pulse {
    animation: pulse 2s cubic-bezier(0.4, 0, 0.6, 1) infinite;
}