/* --- CSS Variables for Global Theming --- */
:root {
    --bg-color: #f0f2f5; /* Light gray background */
    --primary-text-color: #333333;
    --secondary-text-color: #666666;
    --accent-color: #007bff; /* Blue accent for buttons, links */
    --analog-clock-face-color: #ffffff;
    --analog-clock-border-color: #cccccc;
    --hour-hand-color: var(--primary-text-color);
    --minute-hand-color: var(--primary-text-color);
    --second-hand-color: #dc3545; /* Red */
    --center-point-color: var(--second-hand-color);
    --digital-display-bg: #e9ecef;
    --digital-time-color: var(--primary-text-color);
    --digital-date-color: var(--secondary-text-color);
    --button-bg-color: var(--accent-color);
    --button-text-color: #ffffff;
    --shadow-light: 0 4px 15px rgba(0, 0, 0, 0.1);
    --shadow-medium: 0 8px 25px rgba(0, 0, 0, 0.15);
    --transition-duration-theme: 0.5s ease-in-out;
    --transition-duration-hands: 0.2s ease-out; /* Smoother hand movement */
    --font-family-body: 'Poppins', sans-serif;
    --font-family-display: 'Poppins', monospace; /* Monospace for digital time */
}

/* --- Theme Specific Overrides --- */
/* Dark Theme */
html.dark {
    --bg-color: #2c3e50;
    --primary-text-color: #ecf0f1;
    --secondary-text-color: #bdc3c7;
    --accent-color: #3498db;
    --analog-clock-face-color: #34495e;
    --analog-clock-border-color: #2c3e50;
    --hour-hand-color: var(--primary-text-color);
    --minute-hand-color: var(--primary-text-color);
    --second-hand-color: #e74c3c;
    --center-point-color: var(--second-hand-color);
    --digital-display-bg: #212121; /* Slightly darker */
    --digital-time-color: #00ff00; /* Green LED effect */
    --digital-date-color: #00cc00;
    --button-bg-color: var(--accent-color);
}

/* Custom Theme (example) */
html.custom {
    --bg-color: #fce4ec; /* Light pink */
    --primary-text-color: #880e4f; /* Dark magenta */
    --secondary-text-color: #ad1457;
    --accent-color: #ec407a; /* Pink */
    --analog-clock-face-color: #ffe0b2; /* Light orange */
    --analog-clock-border-color: #ffcc80;
    --hour-hand-color: var(--primary-text-color);
    --minute-hand-color: var(--primary-text-color);
    --second-hand-color: #d81b60; /* Dark pink */
    --center-point-color: var(--second-hand-color);
    --digital-display-bg: #f8bbd0;
    --digital-time-color: #4a148c; /* Purple */
    --digital-date-color: #7b1fa2;
    --button-bg-color: var(--accent-color);
}

/* Vibrant Theme (example) */
html.vibrant {
    --bg-color: #4CAF50; /* Green */
    --primary-text-color: #fff;
    --secondary-text-color: #e0f2f1;
    --accent-color: #FFC107; /* Amber */
    --analog-clock-face-color: #8BC34A; /* Light Green */
    --analog-clock-border-color: #689F38;
    --hour-hand-color: #fff;
    --minute-hand-color: #fff;
    --second-hand-color: #FF5722; /* Deep Orange */
    --center-point-color: var(--second-hand-color);
    --digital-display-bg: #2E7D32; /* Darker Green */
    --digital-time-color: #FFECB3; /* Lighter Amber */
    --digital-date-color: #FFD54F;
    --button-bg-color: var(--accent-color);
}

/* --- Base Styles --- */
body {
    font-family: var(--font-family-body);
    background-color: var(--bg-color);
    color: var(--primary-text-color);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    margin: 0;
    padding: 0;
    transition: background-color var(--transition-duration-theme), color var(--transition-duration-theme);
}

/* --- Global Header --- */
.site-header {
    background-color: var(--primary-text-color); /* Matches current primary text color */
    color: var(--analog-clock-face-color); /* Matches current analog face color */
    padding: 15px 0;
    box-shadow: var(--shadow-light);
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.site-brand a {
    font-family: var(--font-family-body);
    font-size: 1.6rem;
    font-weight: 600;
    color: inherit; /* Inherit from parent (header-container) */
    text-decoration: none;
    transition: color var(--transition-duration-hands);
}

.site-brand a:hover {
    color: var(--accent-color);
}

.main-nav ul {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    gap: 25px;
}

.main-nav a {
    color: inherit; /* Inherit from parent */
    text-decoration: none;
    font-weight: 400;
    font-size: 0.95rem;
    position: relative;
    padding-bottom: 5px;
    transition: color var(--transition-duration-hands);
}

.main-nav a::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 0%;
    height: 2px;
    background-color: var(--accent-color);
    transition: width var(--transition-duration-hands);
}

.main-nav a:hover {
    color: var(--accent-color);
}

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

/* --- Main Content Section --- */
.main-content {
    flex-grow: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
    box-sizing: border-box;
}

.clock-app-section {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 30px;
    max-width: 900px;
    width: 100%;
    margin: auto;
    padding: 30px;
    background-color: var(--analog-clock-face-color); /* Clock face color as section bg */
    border-radius: 15px;
    box-shadow: var(--shadow-medium);
    transition: background-color var(--transition-duration-theme);
}

.app-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-text-color);
    margin-bottom: 10px;
    text-align: center;
    transition: color var(--transition-duration-theme);
}

.clock-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 25px;
    position: relative; /* For preview wrapper positioning */
    width: 100%;
    max-width: 500px;
}

/* --- Analog Clock --- */
.clock {
    position: relative;
    width: 300px;
    height: 300px;
    border-radius: 50%;
    background-color: var(--analog-clock-face-color);
    border: 5px solid var(--analog-clock-border-color);
    box-shadow: inset 0 0 10px rgba(0, 0, 0, 0.1), 0 0 0 5px var(--analog-clock-border-color);
    display: flex;
    justify-content: center;
    align-items: center;
    transition: background-color var(--transition-duration-theme), border-color var(--transition-duration-theme), box-shadow var(--transition-duration-theme);
}

.center-point {
    position: absolute;
    width: 15px;
    height: 15px;
    border-radius: 50%;
    background-color: var(--center-point-color);
    z-index: 10;
    transition: background-color var(--transition-duration-theme);
}

.needle {
    position: absolute;
    top: 50%;
    left: 50%;
    transform-origin: 0% 100%; /* Rotate from bottom-center */
    transform: translate(-50%, -100%) rotate(0deg); /* Initial position */
    border-radius: 5px 5px 0 0; /* Rounded top */
    z-index: 5;
    transition: transform var(--transition-duration-hands); /* Smooth rotation */
}

.needle.hour {
    width: 8px;
    height: 80px;
    background-color: var(--hour-hand-color);
    z-index: 7;
    transition: transform var(--transition-duration-hands), background-color var(--transition-duration-theme);
}

.needle.minute {
    width: 6px;
    height: 110px;
    background-color: var(--minute-hand-color);
    z-index: 8;
    transition: transform var(--transition-duration-hands), background-color var(--transition-duration-theme);
}

.needle.second {
    width: 2px;
    height: 120px;
    background-color: var(--second-hand-color);
    z-index: 9;
    transition: transform var(--transition-duration-hands), background-color var(--transition-duration-theme);
}

/* Clock Marks */
.mark {
    position: absolute;
    background-color: var(--primary-text-color);
    transition: background-color var(--transition-duration-theme);
}

.mark-12,.mark-3,.mark-6,.mark-9 {
    width: 4px;
    height: 15px;
    position: absolute;
    transform-origin: center;
    background-color: var(--primary-text-color);
    border-radius: 2px;
}
.mark-12 { top: 10px; left: calc(50% - 2px); }
.mark-3 { right: 10px; top: calc(50% - 7.5px); transform: rotate(90deg); }
.mark-6 { bottom: 10px; left: calc(50% - 2px); }
.mark-9 { left: 10px; top: calc(50% - 7.5px); transform: rotate(-90deg); }

/* --- Digital Display --- */
.digital-display {
    text-align: center;
    background-color: var(--digital-display-bg);
    padding: 15px 25px;
    border-radius: 10px;
    box-shadow: var(--shadow-light);
    transition: background-color var(--transition-duration-theme);
}

.time {
    font-family: var(--font-family-display);
    font-size: 3.5rem;
    font-weight: 600;
    color: var(--digital-time-color);
    margin: 0;
    line-height: 1;
    transition: color var(--transition-duration-theme);
}

.date {
    font-size: 1.1rem;
    color: var(--digital-date-color);
    margin-top: 5px;
    transition: color var(--transition-duration-theme);
}

.gmt-offset {
    font-size: 0.9rem;
    color: var(--digital-date-color);
    margin-top: 5px;
    transition: color var(--transition-duration-theme);
}

/* --- Theme Switcher --- */
.theme-switcher {
    display: flex;
    gap: 10px;
    margin-top: 20px;
    flex-wrap: wrap;
    justify-content: center;
}

.theme-btn {
    background-color: var(--button-bg-color);
    color: var(--button-text-color);
    border: none;
    padding: 10px 20px;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    box-shadow: var(--shadow-light);
    transition: background-color var(--transition-duration-hands), transform 0.2s ease-out, box-shadow var(--transition-duration-hands);
    outline: none; /* Remove default outline */
}

.theme-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-medium);
}

.theme-btn:focus-visible { /* Custom focus state */
    outline: 3px solid var(--accent-color);
    outline-offset: 3px;
}

.theme-btn[aria-pressed="true"] {
    background-color: var(--accent-color); /* Highlight active button */
    box-shadow: inset 0 0 8px rgba(0, 0, 0, 0.3);
    transform: none; /* No lift */
    pointer-events: none; /* Prevent clicking active button */
}

/* --- Custom Theme Options --- */
.custom-theme-options {
    margin-top: 25px;
    padding: 20px;
    border: 1px solid var(--analog-clock-border-color);
    border-radius: 10px;
    display: flex;
    flex-direction: column;
    gap: 15px;
    background-color: var(--analog-clock-face-color);
    box-shadow: var(--shadow-light);
    transition: background-color var(--transition-duration-theme), border-color var(--transition-duration-theme);
    max-width: 300px;
    width: 100%;
}

.custom-theme-options[aria-hidden="true"] {
    display: none;
}

.custom-theme-options h3 {
    font-size: 1.2rem;
    color: var(--primary-text-color);
    margin-bottom: 10px;
    transition: color var(--transition-duration-theme);
}

.color-picker-group {
    display: flex;
    align-items: center;
    justify-content: space-between;
    color: var(--primary-text-color);
    transition: color var(--transition-duration-theme);
}

.color-picker-group label {
    font-weight: 400;
}

.color-picker-group input[type="color"] {
    width: 60px;
    height: 30px;
    border: none;
    padding: 0;
    cursor: pointer;
    border-radius: 5px;
}

#apply-custom-colors, #reset-custom-colors {
    width: 100%;
    padding: 10px;
    border-radius: 8px;
    border: none;
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    box-shadow: var(--shadow-light);
    transition: background-color var(--transition-duration-hands), transform 0.2s ease-out;
}

#apply-custom-colors {
    background-color: var(--accent-color);
    color: #ffffff;
}

#apply-custom-colors:hover {
    background-color: darken(var(--accent-color), 10%); /* This would require a preprocessor */
    transform: translateY(-1px);
}

#reset-custom-colors {
    background-color: var(--secondary-text-color);
    color: #ffffff;
    margin-top: 10px;
}

#reset-custom-colors:hover {
    background-color: darken(var(--secondary-text-color), 10%);
    transform: translateY(-1px);
}

/* --- Theme Preview --- */
.theme-preview-wrapper {
    margin-top: 30px;
    padding: 20px;
    background-color: var(--analog-clock-face-color);
    border-radius: 10px;
    box-shadow: var(--shadow-light);
    text-align: center;
    max-width: 250px;
    transition: background-color var(--transition-duration-theme);
}

.theme-preview-wrapper[aria-hidden="true"] {
    display: none;
}

.preview-title {
    font-size: 1.2rem;
    color: var(--primary-text-color);
    margin-bottom: 15px;
    transition: color var(--transition-duration-theme);
}

.theme-preview {
    position: relative;
    width: 150px;
    height: 150px;
    border-radius: 50%;
    background-color: var(--analog-clock-face-color);
    border: 3px solid var(--analog-clock-border-color);
    margin: 15px auto;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: background-color var(--transition-duration-theme), border-color var(--transition-duration-theme);
}

.theme-preview-center-point {
    position: absolute;
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background-color: var(--center-point-color);
    z-index: 10;
    transition: background-color var(--transition-duration-theme);
}

.theme-preview-needle {
    position: absolute;
    top: 50%;
    left: 50%;
    transform-origin: 0% 100%;
    transform: translate(-50%, -100%) rotate(0deg);
    border-radius: 3px 3px 0 0;
    transition: background-color var(--transition-duration-theme);
}

.theme-preview-needle.hour {
    width: 5px;
    height: 40px;
    background-color: var(--hour-hand-color);
    z-index: 7;
}

.theme-preview-needle.minute {
    width: 4px;
    height: 60px;
    background-color: var(--minute-hand-color);
    z-index: 8;
}

.theme-preview-needle.second {
    width: 1px;
    height: 65px;
    background-color: var(--second-hand-color);
    z-index: 9;
}

.theme-preview-digital-display {
    margin-top: 10px;
    color: var(--digital-time-color);
    font-family: var(--font-family-display);
    transition: color var(--transition-duration-theme);
}

.theme-preview-time {
    font-size: 1.2rem;
    font-weight: 600;
}

.theme-preview-date {
    font-size: 0.8rem;
    color: var(--digital-date-color);
}

/* --- Global Footer --- */
.site-footer {
    background-color: var(--primary-text-color);
    color: var(--analog-clock-face-color);
    padding: 30px 20px;
    font-size: 0.9rem;
    box-shadow: var(--shadow-light);
    margin-top: 40px;
    transition: background-color var(--transition-duration-theme), color var(--transition-duration-theme);
}

.footer-container {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 30px;
    padding-bottom: 20px; /* Space above bottom section */
}

.footer-brand a {
    font-family: var(--font-family-body);
    font-size: 1.4rem;
    font-weight: 600;
    color: var(--analog-clock-face-color);
    text-decoration: none;
    transition: color var(--transition-duration-hands);
    display: block; /* Ensures tagline is below */
    margin-bottom: 5px;
}

.footer-brand a:hover {
    color: var(--accent-color);
}

.footer-brand.tagline {
    font-style: italic;
    font-size: 0.85rem;
    color: var(--secondary-text-color);
    margin-top: 0;
    transition: color var(--transition-duration-theme);
}

.site-footer h4 {
    font-size: 1.05rem;
    font-weight: 600;
    color: var(--analog-clock-face-color);
    margin-bottom: 15px;
    transition: color var(--transition-duration-theme);
}

.site-footer ul {
    list-style: none;
    margin: 0;
    padding: 0;
}

.site-footer ul li {
    margin-bottom: 8px;
}

.site-footer a {
    color: var(--secondary-text-color);
    text-decoration: none;
    transition: color var(--transition-duration-hands);
}

.site-footer a:hover {
    color: var(--accent-color);
}

.social-icons {
    display: flex;
    gap: 12px;
    margin-top: 10px;
}

.social-icons a {
    color: var(--analog-clock-face-color);
    transition: color var(--transition-duration-hands), transform 0.2s ease-out;
}

.social-icons a:hover {
    color: var(--accent-color);
    transform: translateY(-3px);
}

.social-icons svg {
    width: 20px;
    height: 20px;
    vertical-align: middle;
}

.footer-contact p {
    margin: 5px 0;
}

.footer-contact a {
    display: inline-block; /* Ensure link spans text */
}

.footer-bottom {
    grid-column: 1 / -1;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    margin-top: 30px;
    padding-top: 20px;
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: center;
    font-size: 0.8rem;
    color: var(--secondary-text-color);
    transition: color var(--transition-duration-theme);
}

.footer-bottom.copyright {
    margin: 0;
    flex-grow: 1; /* Allow it to take space */
}

.footer-bottom.privacy-terms {
    display: flex;
    gap: 15px;
}

.footer-bottom.privacy-terms a {
    color: var(--secondary-text-color);
}
.footer-bottom.privacy-terms.separator {
    color: var(--secondary-text-color);
    opacity: 0.6;
}

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

/* --- Responsive Adjustments --- */
@media (max-width: 768px) {
   .header-container {
        flex-direction: column;
        gap: 15px;
    }
   .main-nav ul {
        gap: 15px;
        flex-wrap: wrap;
        justify-content: center;
    }
   .app-title {
        font-size: 2rem;
    }
   .clock-container {
        padding: 0 15px;
    }
   .digital-display {
        padding: 10px 20px;
    }
   .time {
        font-size: 3rem;
    }
   .date,.gmt-offset {
        font-size: 0.9rem;
    }
   .theme-switcher {
        flex-direction: column;
        width: 100%;
        max-width: 250px;
    }
   .theme-btn {
        width: 100%;
    }
   .custom-theme-options {
        padding: 15px;
    }
   .footer-container {
        grid-template-columns: 1fr;
        text-align: center;
    }
   .footer-brand,.footer-links,.social-links,.footer-contact {
        align-items: center;
    }
   .footer-links ul,.social-icons {
        justify-content: center;
    }
   .footer-bottom {
        flex-direction: column;
        gap: 10px;
    }
   .footer-bottom.privacy-terms {
        gap: 10px;
    }
}

@media (max-width: 480px) {
   .site-brand a {
        font-size: 1.4rem;
    }
   .main-nav a {
        font-size: 0.85rem;
    }
   .clock {
        width: 250px;
        height: 250px;
    }
   .needle.hour { height: 65px; width: 7px; }
   .needle.minute { height: 90px; width: 5px; }
   .needle.second { height: 100px; width: 1.5px; }
   .digital-display {
        padding: 8px 15px;
    }
   .time {
        font-size: 2.5rem;
    }
   .date,.gmt-offset {
        font-size: 0.8rem;
    }
   .theme-btn {
        padding: 8px 15px;
        font-size: 0.9rem;
    }
   .site-footer {
        padding: 20px 15px;
    }
   .footer-brand a {
        font-size: 1.2rem;
    }
   .site-footer h4 {
        font-size: 0.95rem;
    }
   .social-icons svg {
        width: 18px;
        height: 18px;
    }
}