/* ==========================================================================
   CSS Custom Properties
   ========================================================================== */

:root {
    /* Colors - Refined neutral palette with subtle warmth */
    --color-bg: #f8f9fa;
    --color-bg-alt: #ffffff;
    --color-bg-elevated: #ffffff;
    --color-text: #111827;
    --color-text-secondary: #374151;
    --color-text-muted: #6b7280;
    --color-text-subtle: #9ca3af;
    --color-primary: #111827;
    --color-primary-hover: #374151;
    --color-accent: #3b82f6;
    --color-border: #e5e7eb;
    --color-border-light: #f3f4f6;
    --color-border-subtle: #f0f1f3;

    /* Typography */
    --font-sans: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-mono: ui-monospace, SFMono-Regular, 'SF Mono', Consolas, 'Liberation Mono', Menlo, monospace;

    /* Font Sizes - Refined scale with more contrast */
    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 1.875rem;
    --text-4xl: 2.5rem;
    --text-5xl: 3.75rem;
    --text-6xl: 5rem;

    /* Spacing - More generous scale */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;
    --space-4xl: 6rem;
    --space-5xl: 10rem;

    /* Layout */
    --max-width: 1140px;
    --content-width: 60ch;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 200ms ease;

    /* Shadows - Softer, more refined */
    --shadow-xs: 0 1px 2px 0 rgb(0 0 0 / 0.03);
    --shadow-sm: 0 1px 3px 0 rgb(0 0 0 / 0.04), 0 1px 2px -1px rgb(0 0 0 / 0.04);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.05), 0 2px 4px -2px rgb(0 0 0 / 0.04);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.05), 0 4px 6px -4px rgb(0 0 0 / 0.04);
    --shadow-card: 0 1px 3px 0 rgb(0 0 0 / 0.03), 0 1px 2px -1px rgb(0 0 0 / 0.02);
    --shadow-card-hover: 0 4px 12px -2px rgb(0 0 0 / 0.06), 0 2px 4px -2px rgb(0 0 0 / 0.03);

    /* Border radius - Softer, more modern */
    --radius-sm: 0.375rem;
    --radius-md: 0.625rem;
    --radius-lg: 1rem;
    --radius-xl: 1.25rem;
}

/* ==========================================================================
   CSS Reset (Modern Minimal)
   ========================================================================== */

*,
*::before,
*::after {
    box-sizing: border-box;
}

* {
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    min-height: 100vh;
    line-height: 1.6;
    font-family: var(--font-sans);
    font-size: var(--text-base);
    color: var(--color-text);
    background-color: var(--color-bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

img,
picture,
video,
canvas,
svg {
    display: block;
    max-width: 100%;
}

input,
button,
textarea,
select {
    font: inherit;
}

p,
h1,
h2,
h3,
h4,
h5,
h6 {
    overflow-wrap: break-word;
}

a {
    color: inherit;
    text-decoration: none;
}

ul,
ol {
    list-style: none;
}

/* ==========================================================================
   Base Typography
   ========================================================================== */

h1,
h2,
h3,
h4 {
    line-height: 1.2;
    font-weight: 600;
    letter-spacing: -0.02em;
}

h1 {
    font-size: var(--text-4xl);
}

h2 {
    font-size: var(--text-2xl);
}

h3 {
    font-size: var(--text-xl);
}

p {
    max-width: var(--content-width);
}

p + p {
    margin-top: var(--space-md);
}

/* ==========================================================================
   Layout
   ========================================================================== */

.container {
    width: 100%;
    max-width: var(--max-width);
    margin-inline: auto;
    padding-inline: var(--space-lg);
}

.section {
    padding-block: var(--space-5xl);
    scroll-margin-top: 5rem;
}

.section:nth-child(even) {
    background-color: var(--color-bg-alt);
}

.section__title {
    margin-bottom: var(--space-2xl);
    font-size: var(--text-2xl);
    font-weight: 600;
    letter-spacing: -0.02em;
    color: var(--color-text);
}

/* ==========================================================================
   Navigation
   ========================================================================== */

.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background-color: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border-subtle);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    max-width: var(--max-width);
    margin-inline: auto;
    padding: var(--space-lg) var(--space-lg);
}

.nav__logo {
    font-weight: 700;
    font-size: var(--text-lg);
    letter-spacing: -0.02em;
    color: var(--color-text);
}

.nav__toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    padding: var(--space-sm);
    background: none;
    border: none;
    cursor: pointer;
}

.nav__toggle-bar {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--color-text);
    transition: var(--transition-base);
}

.nav__list {
    display: flex;
    gap: var(--space-xl);
}

.nav__link {
    font-size: var(--text-sm);
    color: var(--color-text-muted);
    transition: color var(--transition-fast);
    position: relative;
}

.nav__link::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 1px;
    background-color: var(--color-text);
    transition: width var(--transition-fast);
}

.nav__link:hover {
    color: var(--color-text);
}

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

/* Mobile navigation */
@media (max-width: 768px) {
    .nav__toggle {
        display: flex;
    }

    .nav__list {
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        flex-direction: column;
        gap: 0;
        padding: var(--space-md) var(--space-lg);
        background-color: var(--color-bg-alt);
        border-bottom: 1px solid var(--color-border);
        display: none;
    }

    .nav__list.is-open {
        display: flex;
    }

    .nav__link {
        display: block;
        padding: var(--space-sm) 0;
    }
}

/* ==========================================================================
   Hero Section
   ========================================================================== */

.hero {
    display: flex;
    align-items: center;
    min-height: calc(100vh - 4rem);
    padding-block: var(--space-5xl);
    background-color: var(--color-bg-alt);
}

.hero__title {
    font-size: clamp(var(--text-5xl), 12vw, var(--text-6xl));
    font-weight: 700;
    letter-spacing: -0.035em;
    line-height: 1.05;
    margin-bottom: var(--space-lg);
    color: var(--color-text);
}

.hero__subtitle {
    font-size: var(--text-sm);
    color: var(--color-text-muted);
    font-weight: 500;
    font-family: var(--font-mono);
    letter-spacing: 0.08em;
    text-transform: uppercase;
    margin-bottom: var(--space-md);
}

.hero__meta {
    font-size: var(--text-sm);
    color: var(--color-text-muted);
    margin-bottom: var(--space-2xl);
    line-height: 1.6;
}

.hero__cert {
    display: inline-block;
    padding: 0.2rem 0.625rem;
    background-color: #ecfdf5;
    color: #047857;
    font-weight: 600;
    border-radius: var(--radius-sm);
    font-size: var(--text-xs);
    letter-spacing: 0.01em;
}

.hero__tagline {
    font-size: var(--text-xl);
    line-height: 1.6;
    color: var(--color-text-secondary);
    max-width: 42ch;
    font-weight: 400;
}

.hero__cta {
    display: flex;
    gap: var(--space-md);
    flex-wrap: wrap;
    margin-top: var(--space-2xl);
}

/* ==========================================================================
   Buttons
   ========================================================================== */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.875rem 1.75rem;
    font-size: var(--text-sm);
    font-weight: 500;
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
    cursor: pointer;
    border: none;
    text-decoration: none;
    letter-spacing: 0.01em;
}

.btn--primary {
    background-color: var(--color-text);
    color: var(--color-bg-alt);
    box-shadow: var(--shadow-sm);
}

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

.btn--secondary {
    background-color: var(--color-bg-alt);
    color: var(--color-text);
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-xs);
}

.btn--secondary:hover {
    border-color: var(--color-text-muted);
    background-color: var(--color-bg);
}

/* ==========================================================================
   About Section
   ========================================================================== */

.about__content {
    max-width: var(--content-width);
}

.about__content p {
    color: var(--color-text-secondary);
    font-size: var(--text-base);
    line-height: 1.75;
}

.about__content p + p {
    margin-top: var(--space-lg);
}

/* ==========================================================================
   Achievements Section
   ========================================================================== */

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

.achievement {
    display: flex;
    flex-direction: column;
    padding: var(--space-xl) var(--space-xl);
    background-color: var(--color-bg-elevated);
    border: 1px solid var(--color-border-subtle);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-card);
}

.achievement__image {
    flex-shrink: 0;
    width: 48px;
    height: 48px;
    border-radius: var(--radius-sm);
    object-fit: cover;
    margin-bottom: var(--space-md);
}

.achievement__content {
    flex: 1;
}

.achievement__label {
    display: inline-block;
    font-size: var(--text-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--color-text-subtle);
    margin-bottom: var(--space-sm);
}

.achievement__title {
    font-size: var(--text-base);
    font-weight: 600;
    line-height: 1.35;
    margin-bottom: var(--space-xs);
    color: var(--color-text);
}

.achievement__subtitle {
    font-size: var(--text-sm);
    color: var(--color-text-muted);
    line-height: 1.5;
}

/* ==========================================================================
   Projects Section
   ========================================================================== */

.section__subtitle {
    color: var(--color-text-muted);
    font-size: var(--text-base);
    max-width: var(--content-width);
    margin-top: calc(-1 * var(--space-md));
    margin-bottom: var(--space-3xl);
    line-height: 1.6;
}

.projects__list {
    display: flex;
    flex-direction: column;
    gap: var(--space-3xl);
}

/* Individual Project */
.project {
    padding: var(--space-2xl) var(--space-2xl) var(--space-xl);
    background-color: var(--color-bg-elevated);
    border: 1px solid var(--color-border-subtle);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-card);
}

.project__header {
    margin-bottom: var(--space-xl);
    padding-bottom: var(--space-lg);
    border-bottom: 1px solid var(--color-border-light);
}

.project__title-row {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    flex-wrap: wrap;
    margin-bottom: var(--space-lg);
}

.project__title {
    font-size: var(--text-2xl);
    letter-spacing: -0.02em;
    color: var(--color-text);
}

.project__title-row .project__title {
    margin-bottom: 0;
}

.project__stack {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-sm);
}

.tag {
    display: inline-block;
    padding: 0.375rem 0.75rem;
    font-size: var(--text-xs);
    font-weight: 500;
    background-color: var(--color-bg);
    border-radius: var(--radius-md);
    color: var(--color-text-muted);
    border: 1px solid var(--color-border-light);
}

.tag--status {
    background-color: #fffbeb;
    color: #b45309;
    border-color: #fde68a;
}

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

.project__section {
    padding: var(--space-lg) var(--space-xl);
    background-color: var(--color-bg);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border-subtle);
}

.project__section-title {
    font-size: var(--text-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--color-text-subtle);
    margin-bottom: var(--space-md);
}

.project__section p {
    color: var(--color-text-secondary);
    font-size: var(--text-sm);
    line-height: 1.7;
}

.project__list {
    font-size: var(--text-sm);
    line-height: 1.75;
    color: var(--color-text-secondary);
}

.project__list li {
    position: relative;
    padding-left: var(--space-lg);
    margin-bottom: var(--space-sm);
}

.project__list li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0.65em;
    width: 5px;
    height: 5px;
    background-color: var(--color-text-subtle);
    border-radius: 50%;
}

.project__footer {
    display: flex;
    gap: var(--space-lg);
    padding-top: var(--space-lg);
    border-top: 1px solid var(--color-border-light);
}

.project__link {
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--color-text);
    transition: color var(--transition-fast);
    display: inline-flex;
    align-items: center;
    gap: 0.375rem;
}

.project__link::after {
    content: '\2192';
    transition: transform var(--transition-fast);
}

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

.project__link:hover::after {
    transform: translateX(3px);
}

/* Responsive: Stack on mobile */
@media (max-width: 768px) {
    .project__content {
        grid-template-columns: 1fr;
    }

    .project {
        padding: var(--space-lg);
    }
}

/* ==========================================================================
   Skills Section
   ========================================================================== */

.skills__grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-2xl);
}

.skill-group__title {
    font-size: var(--text-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--color-text-subtle);
    margin-bottom: var(--space-md);
    padding-bottom: var(--space-sm);
    border-bottom: 1px solid var(--color-border-light);
}

.skill-group__list li {
    padding: var(--space-sm) 0;
    color: var(--color-text-secondary);
    font-size: var(--text-sm);
    line-height: 1.4;
}

/* Certifications */
.skills__certifications {
    margin-top: var(--space-3xl);
    padding-top: var(--space-2xl);
    border-top: 1px solid var(--color-border);
}

.certifications__list {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-md);
}

.certification {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-md) var(--space-lg);
    background-color: var(--color-bg-elevated);
    border: 1px solid var(--color-border-subtle);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xs);
}

.certification__name {
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--color-text);
}

.certification__status {
    font-size: var(--text-xs);
    font-weight: 600;
    padding: 0.25rem 0.625rem;
    background-color: #ecfdf5;
    color: #047857;
    border-radius: var(--radius-sm);
    letter-spacing: 0.01em;
}

.certification__status--pending {
    background-color: #fffbeb;
    color: #b45309;
}

/* ==========================================================================
   Experience Section
   ========================================================================== */

.experience__timeline {
    max-width: var(--content-width);
}

.experience-item {
    padding-left: var(--space-xl);
    padding-bottom: var(--space-2xl);
    border-left: 2px solid var(--color-border-light);
    position: relative;
}

.experience-item::before {
    content: '';
    position: absolute;
    left: -5px;
    top: 0.25rem;
    width: 8px;
    height: 8px;
    background-color: var(--color-text);
    border-radius: 50%;
}

.experience-item:last-child {
    padding-bottom: 0;
}

.experience-item__title {
    margin-bottom: var(--space-sm);
    font-size: var(--text-lg);
    font-weight: 600;
    letter-spacing: -0.01em;
    color: var(--color-text);
}

.experience-item__org {
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--color-text-secondary);
    margin-bottom: var(--space-xs);
}

.experience-item__period {
    font-size: var(--text-xs);
    color: var(--color-text-subtle);
    margin-bottom: var(--space-md);
    font-weight: 500;
    letter-spacing: 0.02em;
}

.experience-item__description {
    color: var(--color-text-muted);
    font-size: var(--text-sm);
    line-height: 1.7;
}

/* ==========================================================================
   Contact Section
   ========================================================================== */

.contact__intro {
    color: var(--color-text-muted);
    font-size: var(--text-lg);
    margin-bottom: var(--space-xl);
    line-height: 1.6;
}

.contact__links {
    display: flex;
    gap: var(--space-xl);
    flex-wrap: wrap;
}

.contact__link {
    font-weight: 500;
    font-size: var(--text-base);
    color: var(--color-text);
    transition: color var(--transition-fast);
    display: inline-flex;
    align-items: center;
    gap: 0.375rem;
}

.contact__link::after {
    content: '\2197';
    font-size: 0.8em;
    transition: transform var(--transition-fast);
}

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

.contact__link:hover::after {
    transform: translate(2px, -2px);
}

/* ==========================================================================
   Footer
   ========================================================================== */

.site-footer {
    padding: var(--space-2xl) 0;
    border-top: 1px solid var(--color-border-light);
    background-color: var(--color-bg);
}

.site-footer p {
    font-size: var(--text-sm);
    color: var(--color-text-subtle);
    text-align: center;
    letter-spacing: 0.01em;
}

/* ==========================================================================
   Mobile Responsive
   ========================================================================== */

@media (max-width: 768px) {
    .section {
        padding-block: var(--space-3xl);
    }

    .section__title {
        font-size: var(--text-xl);
        margin-bottom: var(--space-xl);
    }

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

    .hero {
        min-height: auto;
        padding-block: var(--space-3xl);
    }

    .hero__tagline {
        font-size: var(--text-lg);
    }

    .hero__cta {
        margin-top: var(--space-xl);
    }

    .project {
        padding: var(--space-xl);
    }

    .project__title {
        font-size: var(--text-xl);
    }

    .project__section {
        padding: var(--space-lg);
    }

    .projects__list {
        gap: var(--space-xl);
    }

    .skills__grid {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--space-xl);
    }

    .skills__certifications {
        margin-top: var(--space-xl);
        padding-top: var(--space-lg);
    }

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

    .achievement {
        padding: var(--space-lg) var(--space-xl);
    }

    .experience-item {
        padding-left: var(--space-lg);
        padding-bottom: var(--space-xl);
    }

    .contact__intro {
        font-size: var(--text-base);
    }
}

@media (max-width: 480px) {
    .container {
        padding-inline: var(--space-lg);
    }

    .section {
        padding-block: var(--space-2xl);
    }

    .hero__title {
        font-size: var(--text-4xl);
    }

    .skills__grid {
        grid-template-columns: 1fr;
        gap: var(--space-xl);
    }

    .hero__cta {
        flex-direction: column;
        gap: var(--space-sm);
    }

    .btn {
        width: 100%;
        justify-content: center;
    }

    .certifications__list {
        flex-direction: column;
    }

    .certification {
        width: 100%;
        justify-content: space-between;
    }

    .contact__links {
        gap: var(--space-lg);
    }
}

/* ==========================================================================
   Utilities
   ========================================================================== */

.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;
}