/* 1. CSS RESET */
*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body,
h1,
h2,
h3,
p {
    margin: 0;
}

/* 2. DESIGN TOKENS */
:root {
    /* Colors */
    --color-bg: #0B1120;
    --color-surface: #151E30;
    --color-surface-light: #1D293D;

    --color-primary: #D6B779;
    --color-primary-hover: #E6CC98;

    --color-text: #F5F1E8;
    --color-text-muted: #A5ADBD;

    --color-border: #344157;

    /* Typography */
    --font-primary: 'Segoe UI', Arial, sans-serif;

    /* Spacing */
    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 1.5rem;
    --space-lg: 2rem;
    --space-xl: 3rem;

    /* Layout */
    --container-width: 760px;

    /* Effects */
    --radius-sm: 8px;
    --radius-md: 14px;
    --radius-lg: 20px;

    --shadow-card: 0 12px 40px rgba(0, 0, 0, 0.25);
}

/* 3. GLOBAL STYLES */
body {
    min-height: 100vh;
    font-family: var(--font-primary);
    background:
        radial-gradient(circle at 50% 0%,
            rgba(75, 91, 130, 0.2),
            transparent 45%),
        var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
}

/* 4. MAIN LAYOUT */
.app-shell {
    width: min(100% - 2rem, var(--container-width));
    min-height: 100vh;
    margin-inline: auto;
    padding-block: var(--space-xl);
    display: flex;
    flex-direction: column;
}

/* 5. SITE HEADER */
.site-header {
    text-align: center;
    margin-bottom: var(--space-xl);
}

.site-header h1 {
    font-size: clamp(2rem, 5vw, 3rem);
    line-height: 1.2;
    letter-spacing: -0.04em;
}

.eyebrow {
    color: var(--color-primary);
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.15em;
    text-transform: uppercase;
}

.intro {
    color: var(--color-text-muted);
    margin-top: var(--space-sm);
}

/* ========================================
   6. FORM SECTION
======================================== */

/* Site header spacing */
.site-header {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-sm);
}

.site-header .intro {
    max-width: 480px;
}

/* Form container */
.form-section {
    width: 100%;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-xl);
    box-shadow: var(--shadow-card);
}

/* Form heading */
.form-heading {
    margin-bottom: var(--space-lg);
}

.form-heading h2 {
    font-size: 1.5rem;
    margin-top: var(--space-xs);
}


/* Form layout */
.message-form {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
}

/* Labels */
.form-group label {
    color: var(--color-text);
    font-size: 0.9rem;
    font-weight: 500;
}

/* Textarea and date input */
.form-group textarea,
.form-group input {
    width: 100%;
    padding: 0.9rem 1rem;
    background: var(--color-surface-light);
    color: var(--color-text);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font: inherit;
    outline: none;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

/* Textarea */
.form-group textarea {
    min-height: 150px;
    resize: vertical;
}

.form-group textarea::placeholder {
    color: var(--color-text-muted);
    opacity: 0.7;
}

/* Date picker color */
.form-group input[type="datetime-local"] {
    color-scheme: dark;
}

/* Focus state */
.form-group textarea:focus,
.form-group input:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(214, 183, 121, 0.15);
}


/* Primary button */
.message-form button {
    width: 100%;
    padding: 0.95rem 1.5rem;
    background: var(--color-primary);
    color: var(--color-bg);
    border: none;
    border-radius: var(--radius-sm);
    font: inherit;
    font-weight: 700;
    cursor: pointer;
    transition: background-color 0.2s ease, transform 0.2s ease;
}

/* Hover */
.message-form button:hover {
    background: var(--color-primary-hover);
    transform: translateY(-2px);
}

/* Keyboard focus */
.message-form button:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 4px;
}

/* Active / pressed */
.message-form button:active {
    transform: translateY(0);
}

/* ========================================
   7. LOCKED CAPSULE SECTION
======================================== */

.locked-capsule-section {
    width: 100%;
    padding: var(--space-xl);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-card);
    text-align: center;
}

/* Heading */
.locked-capsule-heading {
    margin-bottom: var(--space-xl);
}

.locked-capsule-heading h2 {
    margin-top: var(--space-sm);
    font-size: 1.6rem;
    line-height: 1.3;
}

/* Countdown heading */
.countdown-heading {
    margin-bottom: var(--space-md);
}

.countdown-heading h3 {
    margin-top: var(--space-xs);
    font-size: 1rem;
    font-weight: 500;
    color: var(--color-text-muted);
}

/* Countdown display */
.countdown-timer {
    margin-bottom: var(--space-lg);
    color: var(--color-primary);
    font-size: clamp(1.8rem, 6vw, 3rem);
    font-weight: 700;
    letter-spacing: 0.04em;
    font-variant-numeric: tabular-nums;
}

/* Supporting message */
.locked-capsule-section>p:last-child {
    max-width: 440px;
    margin-inline: auto;
    color: var(--color-text-muted);
    font-size: 0.9rem;
}

/* ========================================
   8. UNLOCKED CAPSULE SECTION
======================================== */

.unlocked-capsule-section {
    width: 100%;
    padding: var(--space-xl);
    background: var(--color-surface);
    border: 1px solid var(--color-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-card);
    text-align: center;
}

/* Heading */
.unlocked-capsule-heading {
    margin-bottom: var(--space-xl);
}

.unlocked-capsule-heading h2 {
    margin-top: var(--space-sm);
    font-size: 1.6rem;
    line-height: 1.3;
}

/* Revealed message container */
.message-content {
    margin-bottom: var(--space-xl);
    padding: var(--space-lg);
    background: var(--color-surface-light);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    text-align: left;
}

/* Revealed message text */
.unlocked-message {
    color: var(--color-text);
    font-size: 1rem;
    line-height: 1.8;
    white-space: pre-wrap;
    overflow-wrap: anywhere;
}

/* Create another capsule button */
#new-capsule-button {
    width: 100%;
    padding: 0.95rem 1.5rem;
    background: transparent;
    color: var(--color-primary);
    border: 1px solid var(--color-primary);
    border-radius: var(--radius-sm);
    font: inherit;
    font-weight: 600;
    cursor: pointer;
    transition:
        background-color 0.2s ease,
        color 0.2s ease,
        transform 0.2s ease;
}

/* Hover */
#new-capsule-button:hover {
    background: var(--color-primary);
    color: var(--color-bg);
    transform: translateY(-2px);
}

/* Keyboard focus */
#new-capsule-button:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 4px;
}

/* Pressed state */
#new-capsule-button:active {
    transform: translateY(0);
}

/* ========================================
   9. SITE FOOTER
======================================== */

.site-footer {
    margin-top: auto;
    padding-top: var(--space-xl);
    text-align: center;
}

.site-footer p {
    color: var(--color-text-muted);
    font-size: 0.8rem;
}

.site-footer strong {
    color: var(--color-primary);
    font-weight: 600;
}

.site-footer a {
    color: var(--color-accent);
    text-decoration: none;
    transition: color 0.2s ease;
}

.site-footer a:hover {
    text-decoration: underline;
}

.site-footer a:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 4px;
}

/* ========================================
   10. INTERACTION REFINEMENTS
======================================== */

/* Respect reduced-motion preferences */
@media (prefers-reduced-motion: reduce) {

    *,
    *::before,
    *::after {
        scroll-behavior: auto !important;
        transition-duration: 0.01ms !important;
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
    }
}

/* Disabled buttons */
button:disabled {
    opacity: 0.55;
    cursor: not-allowed;
    transform: none;
}

/* Responsive layout */
@media (max-width: 600px) {
    .app-shell {
        padding-block: var(--space-lg);
    }

    .form-section {
        padding: var(--space-md);
    }

    .site-header h1 {
        font-size: 2rem;
    }

    .locked-capsule-section {
        padding: var(--space-md);
    }

    .locked-capsule-heading h2 {
        font-size: 1.35rem;
    }

    .unlocked-capsule-section {
        padding: var(--space-md);
    }

    .unlocked-capsule-heading h2 {
        font-size: 1.35rem;
    }

    .message-content {
        padding: var(--space-md);
    }
}