/* global variables */
:root {
    --primary-color: #ffffff;         /* Terminal white */
    --secondary-color: #808080;       /* Gray for hover */
    --background-dark: #000000;       /* Terminal black */
    --text-color: #ffffff;           /* Terminal white text */
    --text-light: #ffffff;
    --font-mono: 'JetBrains Mono', monospace;
    --cursor-color: #ffffff;
    
    /* Spacing */
    --spacing-sm: 10px;
    --spacing-md: 20px;
    --spacing-lg: 30px;
    
    /* Layout */
    --navbar-height: 60px;
    --container-width: 80%;
    --max-width: 1200px;
}

/* base styles */
html {
    height: 100%;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-mono);
    background-color: var(--background-dark);
    color: var(--text-color);
    line-height: 1.6;
    margin: 0;
    padding: 0;
}

/* prevent unintended cursor animation on all headings */
h1, h2, h3 {
    position: relative;
}

/* blinking cursor on h1 and section headings only */
h1::after {
    content: '_';
    position: absolute;
    right: -25px;
    animation: cursor 1s infinite;
}

section h2::after {
    content: '_';
    position: absolute;
    right: -15px;
    animation: cursor 1s infinite;
}

/* cursor blink animation */
@keyframes cursor {
    0%, 100% { opacity: 1; }
    50% { opacity: 0; }
}

/* typography */
h1 {
    margin: var(--spacing-md) 0;
    font-size: 3em;
}

h2 {
    margin: 25px 0;
    text-align: center;
}

p {
    margin: 25px 0;
    text-align: center;
}

/* layout & grid */
.container {
    width: var(--container-width);
    margin: auto;
    overflow: hidden;
}

.section-content {
    max-width: var(--max-width);
    width: var(--container-width);
    margin: 0 auto;
    padding: 1rem;
    display: flex;
    flex-direction: column;
    align-items: center;
}


.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 400px));
    gap: var(--spacing-lg);
    width: 100%;
    max-width: calc(var(--max-width) - 4rem);
    padding: 0;
    margin: 0 auto;
    justify-content: center;
}

.project-card {
    background: var(--background-dark);
    border: 1px solid var(--primary-color);
    border-radius: 0;
    padding: var(--spacing-md);
    box-shadow: 0 0 10px rgba(255, 255, 255, 0.2);
    transition: transform 0.3s ease;
}

.project-card:hover {
    transform: translateY(-5px);
}

.project-card h3 {
    margin-top: 0;
    color: var(--primary-color);
    text-align: center;;
}

.project-card p {
    font-size: 0.9em;
    line-height: 1.5;
    margin: var(--spacing-md) 0;
}

.project-card p .icon-btn {
    margin-left: 8px;
    color: var(--primary-color);
    text-decoration: none;
    vertical-align: middle;
}

.project-card p .icon-btn:hover {
    color: var(--secondary-color);
}

.project-links {
    display: flex;
    justify-content: flex-end;
    align-items: center;
    margin-top: var(--spacing-md);
}

.project-links .icon-btn {
    color: var(--primary-color);
    text-decoration: none;
    font-size: 1.2em;
    transition: color 0.3s ease;
}

.project-links .icon-btn:hover {
    color: var(--secondary-color);
}

/* skills grid */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-md);
    width: 100%;
    max-width: calc(var(--max-width) - 4rem);
    padding: 1.5rem 0;
    margin: 0 auto;
}

.skill-card {
    background: var(--background-dark);
    border: 1px solid var(--primary-color);
    padding: var(--spacing-sm);
    text-align: center;
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 110px;
}

.skill-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 0 15px rgba(255, 255, 255, 0.2);
    background-color: rgba(255, 255, 255, 0.05);
}

.skill-card i {
    font-size: 2em;
    margin-bottom: 6px;
    color: var(--primary-color);
}

.skill-card h3 {
    margin: 4px 0 0;
    font-size: 0.9em;
    color: var(--text-light);
}

/* navigation */
nav.toolbar {
    background-color: var(--background-dark);
    color: var(--text-light);
    position: fixed;
    top: 0;
    height: var(--navbar-height);
    width: 100%;
    z-index: 1000;
    padding: 0 2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    box-sizing: border-box;
}

nav.toolbar::after {
    content: none;
}

.nav-right {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: flex-end;
}

.theme-toggle {
    background: none;
    border: none;
    color: var(--text-light);
    font-size: 1.2em;
    cursor: pointer;
    padding: 0.4rem 0.5rem;
    transition: color 0.3s ease, transform 0.3s ease;
    display: flex;
    align-items: center;
    font-family: var(--font-mono);
}

.theme-toggle:hover {
    color: var(--secondary-color);
    transform: rotate(20deg);
}

.nav-brand-wrapper {
    flex: 1;
    display: flex;
    align-items: center;
}

.nav-brand {
    color: var(--text-light);
    text-decoration: none;
    font-weight: bold;
    font-size: 1.5em;
    letter-spacing: 2px;
    transition: color 0.2s ease;
    padding: 0.5rem 0;
    position: relative;
}

.nav-brand::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: 0;
    left: 50%;
    background-color: var(--secondary-color);
    transition: all 0.3s ease;
    transform: translateX(-50%);
}

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

.nav-brand:hover {
    color: var(--secondary-color);
}

.nav-brand.active {
    color: var(--primary-color);
}

.nav-brand.active::after {
    background-color: var(--primary-color);
}

.tabs-container {
    display: flex;
    justify-content: center;
    align-items: center;
}

nav.toolbar ul.tabs {
    list-style-type: none;
    padding: 0;
    margin: 0;
    display: flex;
    align-items: center;
    gap: 2rem;
}

nav.toolbar li {
    margin: 0;
}

nav.toolbar .tab {
    color: var(--text-light);
    text-decoration: none;
    padding: 0.5rem 1.5rem;
    display: inline-block;
    background-color: transparent;
    border: 1px solid var(--primary-color);
    border-radius: 4px;
    position: relative;
    transition: all 0.2s ease;
}

nav.toolbar .tab:hover {
    background-color: rgba(255, 255, 255, 0.1);
    box-shadow: 0 0 10px rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}

nav.toolbar .tab.active {
    background-color: rgba(255, 255, 255, 0.15);
    color: var(--primary-color);
    box-shadow: 0 0 15px rgba(255, 255, 255, 0.3);
}

nav.toolbar .tab.active:hover {
    background-color: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}

/* active brand hover */
.nav-brand.active:hover {
    color: var(--secondary-color);
}


/* buttons & links */
.header-buttons {
    margin-top: var(--spacing-lg);
}

.header-buttons .btn {
    display: inline-block;
    margin: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 1em;
    color: var(--primary-color);
    background-color: transparent;
    text-decoration: none;
    border: 1px solid var(--primary-color);
    border-radius: 0;
    transition: all 0.3s ease;
    vertical-align: middle;
}

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

.header-buttons .icon-btn {
    display: inline-block;
    margin: var(--spacing-sm);
    font-size: 1.5em;
    color: var(--text-color);
    text-decoration: none;
    transition: color 0.3s ease;
    vertical-align: middle;
    position: relative;
}

/* underline slide-in animation for icon buttons */
.header-buttons .icon-btn::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -5px;
    left: 50%;
    background-color: var(--primary-color);
    transition: all 0.3s ease;
    transform: translateX(-50%);
}

.header-buttons .icon-btn:hover::after {
    width: 100%;
}

.header-buttons .icon-btn:hover {
    color: var(--secondary-color);
}

/* sections */
header {
    min-height: 90vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: 0;
    width: 100%;
}

header h1 {
    position: relative;
    display: inline-block; /* needed for cursor pseudo-element positioning */
    margin: var(--spacing-md) 0;
    font-size: 3em;
}

header h2 {
    margin: 0;
    font-size: 2em;
    color: var(--text-color);
    padding: var(--spacing-md) 0;
}

header p {
    margin: var(--spacing-md) 0 0;
    font-size: 1.25em;
}

section {
    min-height: 85vh;
    width: 100%;
    padding: 60px var(--spacing-md);
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    align-items: center;
    position: relative;
    padding-top: calc(var(--navbar-height) + 1rem);
    background: var(--background-dark) !important;
}

/* ensure section scroll offset accounts for the fixed navbar */
#projects, #skills, #contact {
    scroll-margin-top: calc(var(--navbar-height) + 1rem);
}

section:nth-child(even) {
    background: var(--background-dark) !important;
}

/* footer */
.footer {
    padding: var(--spacing-md) 0;
    background: var(--background-dark);
    border-top: 1px solid var(--primary-color);
    color: var(--text-light);
    text-align: center;
}

footer p {
    margin: 0;
}

/* contact form */
.contact-form {
    width: 100%;
    max-width: 600px;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
    text-align: left;
}

.form-group label {
    font-size: 0.9em;
    color: var(--secondary-color);
    letter-spacing: 1px;
}

.form-group input,
.form-group textarea {
    background: transparent;
    border: 1px solid var(--primary-color);
    color: var(--text-color);
    font-family: var(--font-mono);
    font-size: 0.95em;
    padding: 0.6rem 0.8rem;
    outline: none;
    transition: box-shadow 0.2s ease, border-color 0.2s ease;
    resize: vertical;
    border-radius: 0;
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--secondary-color);
    opacity: 0.6;
}

.form-group input:focus,
.form-group textarea:focus {
    box-shadow: 0 0 8px rgba(255, 255, 255, 0.25);
    border-color: var(--primary-color);
}

.submit-btn {
    align-self: flex-start;
    cursor: pointer;
    font-family: var(--font-mono);
    font-size: 1em;
}

.submit-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.form-success {
    text-align: center;
    padding: var(--spacing-lg);
    border: 1px solid var(--primary-color);
    color: var(--primary-color);
}

/* light mode form overrides */
[data-theme="light"] .form-group input:focus,
[data-theme="light"] .form-group textarea:focus {
    box-shadow: 0 0 8px rgba(0, 0, 0, 0.15);
}

/* global link styles */
a {
    color: var(--primary-color);
    text-decoration: none;
}

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

/* light mode */
[data-theme="light"] {
    --primary-color: #000000;
    --secondary-color: #555555;
    --background-dark: #ffffff;
    --text-color: #000000;
    --text-light: #000000;
    --cursor-color: #000000;
}

[data-theme="light"] body {
    background-color: #ffffff;
    color: #000000;
}

[data-theme="light"] .project-card {
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.12);
}

[data-theme="light"] .skill-card:hover {
    box-shadow: 0 0 15px rgba(0, 0, 0, 0.12);
    background-color: rgba(0, 0, 0, 0.04);
}

[data-theme="light"] nav.toolbar .tab:hover {
    background-color: rgba(0, 0, 0, 0.06);
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

[data-theme="light"] nav.toolbar .tab.active {
    background-color: rgba(0, 0, 0, 0.08);
    box-shadow: 0 0 15px rgba(0, 0, 0, 0.15);
}

[data-theme="light"] nav.toolbar .tab.active:hover {
    background-color: rgba(0, 0, 0, 0.12);
}

/* mobile / responsive */

/* hamburger hidden on desktop */
.hamburger {
    display: none;
    background: none;
    border: none;
    color: var(--text-light);
    font-size: 1.2em;
    cursor: pointer;
    padding: 0.4rem 0.5rem;
    margin-left: 0.5rem;
    transition: color 0.3s ease;
    font-family: var(--font-mono);
}

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

@media (max-width: 767px) {
    /* show hamburger, hide tab links */
    .hamburger {
        display: flex;
        align-items: center;
    }

    .tabs-container {
        display: none;
        position: absolute;
        top: var(--navbar-height);
        left: 0;
        width: 100%;
        background-color: var(--background-dark);
        border-top: 1px solid var(--primary-color);
        z-index: 999;
        padding: 0.5rem 0;
    }

    /* show menu when nav has .nav-open */
    nav.toolbar.nav-open .tabs-container {
        display: flex;
        flex-direction: column;
        align-items: stretch;
    }

    nav.toolbar ul.tabs {
        flex-direction: column;
        gap: 0;
        width: 100%;
    }

    nav.toolbar ul.tabs li {
        width: 100%;
    }

    nav.toolbar .tab {
        display: block;
        width: 100%;
        text-align: center;
        border: none;
        border-bottom: 1px solid rgba(128, 128, 128, 0.3);
        border-radius: 0;
        padding: 1rem;
    }

    nav.toolbar .tab:hover {
        transform: none;
    }

    nav.toolbar .tab.active {
        box-shadow: none;
    }

    /* scale down hero text */
    h1 {
        font-size: 2em;
    }

    header h1 {
        font-size: 2em;
    }

    header h2 {
        font-size: 1.4em;
    }

    header p {
        font-size: 1em;
        padding: 0 1rem;
    }

    /* tighter section padding */
    section {
        padding-top: calc(var(--navbar-height) + 0.5rem);
        padding-left: 1rem;
        padding-right: 1rem;
    }

    /* single column project/skill cards */
    .projects-grid {
        grid-template-columns: 1fr;
    }

    /* two columns for skill cards on mobile */
    .skills-grid {
        grid-template-columns: repeat(2, 1fr);
        padding: 1rem 0;
        gap: var(--spacing-sm);
    }

    .section-content {
        width: 100%;
        padding: 0.5rem;
    }

    /* light mode mobile menu */
    [data-theme="light"] nav.toolbar .tabs-container {
        background-color: #ffffff;
    }

    [data-theme="light"] nav.toolbar .tab {
        border-bottom-color: rgba(0, 0, 0, 0.15);
    }
}